Merge tag 'trace-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt: - Add function names as a way to filter function addresses - Add sample module to test ftrace ops and dynamic trampolines - Allow stack traces to be passed from beginning event to end event for synthetic events. This will allow seeing the stack trace of when a task is scheduled out and recorded when it gets scheduled back in. - Add trace event helper __get_buf() to use as a temporary buffer when printing out trace event output. - Add kernel command line to create trace instances on boot up. - Add enabling of events to instances created at boot up. - Add trace_array_puts() to write into instances. - Allow boot instances to take a snapshot at the end of boot up. - Allow live patch modules to include trace events - Minor fixes and clean ups * tag 'trace-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (31 commits) tracing: Remove unnecessary NULL assignment tracepoint: Allow livepatch module add trace event tracing: Always use canonical ftrace path tracing/histogram: Fix stacktrace histogram Documententation tracing/histogram: Fix stacktrace key tracing/histogram: Fix a few problems with stacktrace variable printing tracing: Add BUILD_BUG() to make sure stacktrace fits in strings tracing/histogram: Don't use strlen to find length of stacktrace variables tracing: Allow boot instances to have snapshot buffers tracing: Add trace_array_puts() to write into instance tracing: Add enabling of events to boot instances tracing: Add creation of instances at boot command line tracing: Fix trace_event_raw_event_synth() if else statement samples: ftrace: Make some global variables static ftrace: sample: avoid open-coded 64-bit division samples: ftrace: Include the nospec-branch.h only for x86 tracing: Acquire buffer from temparary trace sequence tracing/histogram: Wrap remaining shell snippets in code blocks tracing/osnoise: No need for schedule_hrtimeout range bpf/tracing: Use stage6 of tracing to not duplicate macros ...

Linus Torvalds committed 3 years ago

Commit b72b5fe2 parents 9191423 7568a2142 files · +1113 −221Browse files

Unified · Split

42 files

Documentation/admin-guide/kernel-parameters.txt +29 −0
Documentation/trace/events.rst +12 −0
Documentation/trace/histogram.rst +198 −44
include/linux/kernel.h +1 −1
include/linux/trace.h +12 −0
include/linux/trace_seq.h +5 −0
include/linux/tracepoint.h +2 −2
include/trace/bpf_probe.h +1 −44
include/trace/perf.h +1 −45
include/trace/stages/stage3_trace_output.h +3 −0
include/trace/stages/stage6_event_callback.h +3 −0
include/trace/stages/stage7_class_define.h +1 −0
kernel/trace/Kconfig +10 −10
kernel/trace/kprobe_event_gen_test.c +1 −1
kernel/trace/ring_buffer.c +7 −2
kernel/trace/synth_event_gen_test.c +1 −1
kernel/trace/trace.c +145 −19
kernel/trace/trace.h +6 −0
kernel/trace/trace_events.c +5 −8
kernel/trace/trace_events_filter.c +92 −1
kernel/trace/trace_events_hist.c +103 −23
kernel/trace/trace_events_synth.c +86 −4
kernel/trace/trace_osnoise.c +1 −1
kernel/trace/trace_seq.c +23 −0
kernel/trace/trace_synth.h +1 −0
kernel/tracepoint.c +2 −2
samples/Kconfig +7 −0
samples/Makefile +1 −0
samples/ftrace/Makefile +1 −0
samples/ftrace/ftrace-direct-modify.c +1 −1
samples/ftrace/ftrace-direct-multi-modify.c +1 −1
samples/ftrace/ftrace-direct-multi.c +1 −1
samples/ftrace/ftrace-direct-too.c +1 −1
samples/ftrace/ftrace-direct.c +1 −1
samples/ftrace/ftrace-ops.c +252 −0
samples/user_events/example.c +2 −2
scripts/tracing/draw_functrace.py +3 −3
tools/lib/api/fs/tracing_path.c +2 −2
tools/testing/selftests/ftrace/test.d/filter/event-filter-function.tc +58 −0
tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-stack.tc +24 −0
tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-syntax.tc +6 −0
tools/tracing/latency/latency-collector.c +1 −1

Documentation/admin-guide/kernel-parameters.txt+29−0

@@ -1509,6 +1509,15 @@ · 1508 unmodified lines
1509	boot up that is likely to be overridden by user space	1509	boot up that is likely to be overridden by user space
1510	start up functionality.	1510	start up functionality.
1511		1511
		1512	Optionally, the snapshot can also be defined for a tracing
		1513	instance that was created by the trace_instance= command
		1514	line parameter.
		1515
		1516	trace_instance=foo,sched_switch ftrace_boot_snapshot=foo
		1517
		1518	The above will cause the "foo" tracing instance to trigger
		1519	a snapshot at the end of boot up.
		1520
1512	ftrace_dump_on_oops[=orig_cpu]	1521	ftrace_dump_on_oops[=orig_cpu]
1513	[FTRACE] will dump the trace buffers on oops.	1522	[FTRACE] will dump the trace buffers on oops.
1514	If no parameter is passed, ftrace will dump	1523	If no parameter is passed, ftrace will dump
@@ -6283,6 +6292,26 @@ · 4768 unmodified lines
6283	comma-separated list of trace events to enable. See	6292	comma-separated list of trace events to enable. See
6284	also Documentation/trace/events.rst	6293	also Documentation/trace/events.rst
6285		6294
		6295	trace_instance=[instance-info]
		6296	[FTRACE] Create a ring buffer instance early in boot up.
		6297	This will be listed in:
		6298
		6299	/sys/kernel/tracing/instances
		6300
		6301	Events can be enabled at the time the instance is created
		6302	via:
		6303
		6304	trace_instance=<name>,<system1>:<event1>,<system2>:<event2>
		6305
		6306	Note, the "<system*>:" portion is optional if the event is
		6307	unique.
		6308
		6309	trace_instance=foo,sched:sched_switch,irq_handler_entry,initcall
		6310
		6311	will enable the "sched_switch" event (note, the "sched:" is optional, and
		6312	the same thing would happen if it was left off). The irq_handler_entry
		6313	event, and all events under the "initcall" system.
		6314
6286	trace_options=[option-list]	6315	trace_options=[option-list]
6287	[FTRACE] Enable or disable tracer options at boot.	6316	[FTRACE] Enable or disable tracer options at boot.
6288	The option-list is a comma delimited list of options	6317	The option-list is a comma delimited list of options

Documentation/trace/events.rst+12−0

@@ -207,6 +207,18 @@ field name:: · 206 unmodified lines
207	As the kernel will have to know how to retrieve the memory that the pointer	207	As the kernel will have to know how to retrieve the memory that the pointer
208	is at from user space.	208	is at from user space.
209		209
		210	You can convert any long type to a function address and search by function name::
		211
		212	call_site.function == security_prepare_creds
		213
		214	The above will filter when the field "call_site" falls on the address within
		215	"security_prepare_creds". That is, it will compare the value of "call_site" and
		216	the filter will return true if it is greater than or equal to the start of
		217	the function "security_prepare_creds" and less than the end of that function.
		218
		219	The ".function" postfix can only be attached to values of size long, and can only
		220	be compared with "==" or "!=".
		221
210	5.2 Setting filters	222	5.2 Setting filters
211	-------------------	223	-------------------
212		224

Documentation/trace/histogram.rst+198−44

@@ -81,6 +81,7 @@ Documentation written by Tom Zanussi · 80 unmodified lines
81	.usecs display a common_timestamp in microseconds	81	.usecs display a common_timestamp in microseconds
82	.percent display a number of percentage value	82	.percent display a number of percentage value
83	.graph display a bar-graph of a value	83	.graph display a bar-graph of a value
		84	.stacktrace display as a stacktrace (must by a long[] type)
84	============= =================================================	85	============= =================================================
85		86
86	Note that in general the semantics of a given field aren't	87	Note that in general the semantics of a given field aren't
@@ -1786,6 +1787,8 @@ or assigned to a variable and referenced in a subsequent expression:: · 1699 unmodified lines
1786	# echo 'hist:keys=next_pid:us_per_sec=1000000 ...' >> event/trigger	1787	# echo 'hist:keys=next_pid:us_per_sec=1000000 ...' >> event/trigger
1787	# echo 'hist:keys=next_pid:timestamp_secs=common_timestamp/$us_per_sec ...' >> event/trigger	1788	# echo 'hist:keys=next_pid:timestamp_secs=common_timestamp/$us_per_sec ...' >> event/trigger
1788		1789
		1790	Variables can even hold stacktraces, which are useful with synthetic events.
		1791
1789	2.2.2 Synthetic Events	1792	2.2.2 Synthetic Events
1790	----------------------	1793	----------------------
1791		1794
@@ -1861,7 +1864,7 @@ A histogram can now be defined for the new synthetic event:: · 69 unmodified lines
1861	The above shows the latency "lat" in a power of 2 grouping.	1864	The above shows the latency "lat" in a power of 2 grouping.
1862		1865
1863	Like any other event, once a histogram is enabled for the event, the	1866	Like any other event, once a histogram is enabled for the event, the
1864	output can be displayed by reading the event's 'hist' file.	1867	output can be displayed by reading the event's 'hist' file::
1865		1868
1866	# cat /sys/kernel/tracing/events/synthetic/wakeup_latency/hist	1869	# cat /sys/kernel/tracing/events/synthetic/wakeup_latency/hist
1867		1870
@@ -1908,7 +1911,7 @@ output can be displayed by reading the event's 'hist' file. · 40 unmodified lines
1908		1911
1909		1912
1910	The latency values can also be grouped linearly by a given size with	1913	The latency values can also be grouped linearly by a given size with
1911	the ".buckets" modifier and specify a size (in this case groups of 10).	1914	the ".buckets" modifier and specify a size (in this case groups of 10)::
1912		1915
1913	# echo 'hist:keys=pid,prio,lat.buckets=10:sort=lat' >> \	1916	# echo 'hist:keys=pid,prio,lat.buckets=10:sort=lat' >> \
1914	/sys/kernel/tracing/events/synthetic/wakeup_latency/trigger	1917	/sys/kernel/tracing/events/synthetic/wakeup_latency/trigger
@@ -1940,6 +1943,157 @@ the ".buckets" modifier and specify a size (in this case groups of 10). · 25 unmodified lines
1940	Entries: 16	1943	Entries: 16
1941	Dropped: 0	1944	Dropped: 0
1942		1945
		1946	To save stacktraces, create a synthetic event with a field of type "unsigned long[]"
		1947	or even just "long[]". For example, to see how long a task is blocked in an
		1948	uninterruptible state::
		1949
		1950	# cd /sys/kernel/tracing
		1951	# echo 's:block_lat pid_t pid; u64 delta; unsigned long[] stack;' > dynamic_events
		1952	# echo 'hist:keys=next_pid:ts=common_timestamp.usecs,st=stacktrace if prev_state == 2' >> events/sched/sched_switch/trigger
		1953	# echo 'hist:keys=prev_pid:delta=common_timestamp.usecs-$ts,s=$st:onmax($delta).trace(block_lat,prev_pid,$delta,$s)' >> events/sched/sched_switch/trigger
		1954	# echo 1 > events/synthetic/block_lat/enable
		1955	# cat trace
		1956
		1957	# tracer: nop
		1958	#
		1959	# entries-in-buffer/entries-written: 2/2 #P:8
		1960	#
		1961	# _-----=> irqs-off/BH-disabled
		1962	# / _----=> need-resched
		1963	# \| / _---=> hardirq/softirq
		1964	# \|\| / _--=> preempt-depth
		1965	# \|\|\| / _-=> migrate-disable
		1966	# \|\|\|\| / delay
		1967	# TASK-PID CPU# \|\|\|\|\| TIMESTAMP FUNCTION
		1968	# \| \| \| \|\|\|\|\| \| \|
		1969	<idle>-0 [005] d..4. 521.164922: block_lat: pid=0 delta=8322 stack=STACK:
		1970	=> __schedule+0x448/0x7b0
		1971	=> schedule+0x5a/0xb0
		1972	=> io_schedule+0x42/0x70
		1973	=> bit_wait_io+0xd/0x60
		1974	=> __wait_on_bit+0x4b/0x140
		1975	=> out_of_line_wait_on_bit+0x91/0xb0
		1976	=> jbd2_journal_commit_transaction+0x1679/0x1a70
		1977	=> kjournald2+0xa9/0x280
		1978	=> kthread+0xe9/0x110
		1979	=> ret_from_fork+0x2c/0x50
		1980
		1981	<...>-2 [004] d..4. 525.184257: block_lat: pid=2 delta=76 stack=STACK:
		1982	=> __schedule+0x448/0x7b0
		1983	=> schedule+0x5a/0xb0
		1984	=> schedule_timeout+0x11a/0x150
		1985	=> wait_for_completion_killable+0x144/0x1f0
		1986	=> __kthread_create_on_node+0xe7/0x1e0
		1987	=> kthread_create_on_node+0x51/0x70
		1988	=> create_worker+0xcc/0x1a0
		1989	=> worker_thread+0x2ad/0x380
		1990	=> kthread+0xe9/0x110
		1991	=> ret_from_fork+0x2c/0x50
		1992
		1993	A synthetic event that has a stacktrace field may use it as a key in
		1994	histogram::
		1995
		1996	# echo 'hist:keys=delta.buckets=100,stack.stacktrace:sort=delta' > events/synthetic/block_lat/trigger
		1997	# cat events/synthetic/block_lat/hist
		1998
		1999	# event histogram
		2000	#
		2001	# trigger info: hist:keys=delta.buckets=100,stack.stacktrace:vals=hitcount:sort=delta.buckets=100:size=2048 [active]
		2002	#
		2003	{ delta: ~ 0-99, stack.stacktrace __schedule+0xa19/0x1520
		2004	schedule+0x6b/0x110
		2005	io_schedule+0x46/0x80
		2006	bit_wait_io+0x11/0x80
		2007	__wait_on_bit+0x4e/0x120
		2008	out_of_line_wait_on_bit+0x8d/0xb0
		2009	__wait_on_buffer+0x33/0x40
		2010	jbd2_journal_commit_transaction+0x155a/0x19b0
		2011	kjournald2+0xab/0x270
		2012	kthread+0xfa/0x130
		2013	ret_from_fork+0x29/0x50
		2014	} hitcount: 1
		2015	{ delta: ~ 0-99, stack.stacktrace __schedule+0xa19/0x1520
		2016	schedule+0x6b/0x110
		2017	io_schedule+0x46/0x80
		2018	rq_qos_wait+0xd0/0x170
		2019	wbt_wait+0x9e/0xf0
		2020	__rq_qos_throttle+0x25/0x40
		2021	blk_mq_submit_bio+0x2c3/0x5b0
		2022	__submit_bio+0xff/0x190
		2023	submit_bio_noacct_nocheck+0x25b/0x2b0
		2024	submit_bio_noacct+0x20b/0x600
		2025	submit_bio+0x28/0x90
		2026	ext4_bio_write_page+0x1e0/0x8c0
		2027	mpage_submit_page+0x60/0x80
		2028	mpage_process_page_bufs+0x16c/0x180
		2029	mpage_prepare_extent_to_map+0x23f/0x530
		2030	} hitcount: 1
		2031	{ delta: ~ 0-99, stack.stacktrace __schedule+0xa19/0x1520
		2032	schedule+0x6b/0x110
		2033	schedule_hrtimeout_range_clock+0x97/0x110
		2034	schedule_hrtimeout_range+0x13/0x20
		2035	usleep_range_state+0x65/0x90
		2036	__intel_wait_for_register+0x1c1/0x230 [i915]
		2037	intel_psr_wait_for_idle_locked+0x171/0x2a0 [i915]
		2038	intel_pipe_update_start+0x169/0x360 [i915]
		2039	intel_update_crtc+0x112/0x490 [i915]
		2040	skl_commit_modeset_enables+0x199/0x600 [i915]
		2041	intel_atomic_commit_tail+0x7c4/0x1080 [i915]
		2042	intel_atomic_commit_work+0x12/0x20 [i915]
		2043	process_one_work+0x21c/0x3f0
		2044	worker_thread+0x50/0x3e0
		2045	kthread+0xfa/0x130
		2046	} hitcount: 3
		2047	{ delta: ~ 0-99, stack.stacktrace __schedule+0xa19/0x1520
		2048	schedule+0x6b/0x110
		2049	schedule_timeout+0x11e/0x160
		2050	__wait_for_common+0x8f/0x190
		2051	wait_for_completion+0x24/0x30
		2052	__flush_work.isra.0+0x1cc/0x360
		2053	flush_work+0xe/0x20
		2054	drm_mode_rmfb+0x18b/0x1d0 [drm]
		2055	drm_mode_rmfb_ioctl+0x10/0x20 [drm]
		2056	drm_ioctl_kernel+0xb8/0x150 [drm]
		2057	drm_ioctl+0x243/0x560 [drm]
		2058	__x64_sys_ioctl+0x92/0xd0
		2059	do_syscall_64+0x59/0x90
		2060	entry_SYSCALL_64_after_hwframe+0x72/0xdc
		2061	} hitcount: 1
		2062	{ delta: ~ 0-99, stack.stacktrace __schedule+0xa19/0x1520
		2063	schedule+0x6b/0x110
		2064	schedule_timeout+0x87/0x160
		2065	__wait_for_common+0x8f/0x190
		2066	wait_for_completion_timeout+0x1d/0x30
		2067	drm_atomic_helper_wait_for_flip_done+0x57/0x90 [drm_kms_helper]
		2068	intel_atomic_commit_tail+0x8ce/0x1080 [i915]
		2069	intel_atomic_commit_work+0x12/0x20 [i915]
		2070	process_one_work+0x21c/0x3f0
		2071	worker_thread+0x50/0x3e0
		2072	kthread+0xfa/0x130
		2073	ret_from_fork+0x29/0x50
		2074	} hitcount: 1
		2075	{ delta: ~ 100-199, stack.stacktrace __schedule+0xa19/0x1520
		2076	schedule+0x6b/0x110
		2077	schedule_hrtimeout_range_clock+0x97/0x110
		2078	schedule_hrtimeout_range+0x13/0x20
		2079	usleep_range_state+0x65/0x90
		2080	pci_set_low_power_state+0x17f/0x1f0
		2081	pci_set_power_state+0x49/0x250
		2082	pci_finish_runtime_suspend+0x4a/0x90
		2083	pci_pm_runtime_suspend+0xcb/0x1b0
		2084	__rpm_callback+0x48/0x120
		2085	rpm_callback+0x67/0x70
		2086	rpm_suspend+0x167/0x780
		2087	rpm_idle+0x25a/0x380
		2088	pm_runtime_work+0x93/0xc0
		2089	process_one_work+0x21c/0x3f0
		2090	} hitcount: 1
		2091
		2092	Totals:
		2093	Hits: 10
		2094	Entries: 7
		2095	Dropped: 0
		2096
1943	2.2.3 Hist trigger 'handlers' and 'actions'	2097	2.2.3 Hist trigger 'handlers' and 'actions'
1944	-------------------------------------------	2098	-------------------------------------------
1945		2099
@@ -2054,11 +2208,11 @@ The following commonly-used handler.action pairs are available: · 108 unmodified lines
2054	wakeup_new_test($testpid) if comm=="cyclictest"' >> \	2208	wakeup_new_test($testpid) if comm=="cyclictest"' >> \
2055	/sys/kernel/tracing/events/sched/sched_wakeup_new/trigger	2209	/sys/kernel/tracing/events/sched/sched_wakeup_new/trigger
2056		2210
2057	Or, equivalently, using the 'trace' keyword syntax:	2211	Or, equivalently, using the 'trace' keyword syntax::
2058		2212
2059	# echo 'hist:keys=$testpid:testpid=pid:onmatch(sched.sched_wakeup_new).\	2213	# echo 'hist:keys=$testpid:testpid=pid:onmatch(sched.sched_wakeup_new).\
2060	trace(wakeup_new_test,$testpid) if comm=="cyclictest"' >> \	2214	trace(wakeup_new_test,$testpid) if comm=="cyclictest"' >> \
2061	/sys/kernel/tracing/events/sched/sched_wakeup_new/trigger	2215	/sys/kernel/tracing/events/sched/sched_wakeup_new/trigger
2062		2216
2063	Creating and displaying a histogram based on those events is now	2217	Creating and displaying a histogram based on those events is now
2064	just a matter of using the fields and new synthetic event in the	2218	just a matter of using the fields and new synthetic event in the
@@ -2191,48 +2345,48 @@ The following commonly-used handler.action pairs are available: · 126 unmodified lines
2191	resulting latency, stored in wakeup_lat, exceeds the current	2345	resulting latency, stored in wakeup_lat, exceeds the current
2192	maximum latency, a snapshot is taken. As part of the setup, all	2346	maximum latency, a snapshot is taken. As part of the setup, all
2193	the scheduler events are also enabled, which are the events that	2347	the scheduler events are also enabled, which are the events that
2194	will show up in the snapshot when it is taken at some point:	2348	will show up in the snapshot when it is taken at some point::
2195		2349
2196	# echo 1 > /sys/kernel/tracing/events/sched/enable	2350	# echo 1 > /sys/kernel/tracing/events/sched/enable
2197		2351
2198	# echo 'hist:keys=pid:ts0=common_timestamp.usecs \	2352	# echo 'hist:keys=pid:ts0=common_timestamp.usecs \
2199	if comm=="cyclictest"' >> \	2353	if comm=="cyclictest"' >> \
2200	/sys/kernel/tracing/events/sched/sched_waking/trigger	2354	/sys/kernel/tracing/events/sched/sched_waking/trigger
2201		2355
2202	# echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0: \	2356	# echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0: \
2203	onmax($wakeup_lat).save(next_prio,next_comm,prev_pid,prev_prio, \	2357	onmax($wakeup_lat).save(next_prio,next_comm,prev_pid,prev_prio, \
2204	prev_comm):onmax($wakeup_lat).snapshot() \	2358	prev_comm):onmax($wakeup_lat).snapshot() \
2205	if next_comm=="cyclictest"' >> \	2359	if next_comm=="cyclictest"' >> \
2206	/sys/kernel/tracing/events/sched/sched_switch/trigger	2360	/sys/kernel/tracing/events/sched/sched_switch/trigger
2207		2361
2208	When the histogram is displayed, for each bucket the max value	2362	When the histogram is displayed, for each bucket the max value
2209	and the saved values corresponding to the max are displayed	2363	and the saved values corresponding to the max are displayed
2210	following the rest of the fields.	2364	following the rest of the fields.
2211		2365
2212	If a snapshot was taken, there is also a message indicating that,	2366	If a snapshot was taken, there is also a message indicating that,
2213	along with the value and event that triggered the global maximum:	2367	along with the value and event that triggered the global maximum::
2214		2368
2215	# cat /sys/kernel/tracing/events/sched/sched_switch/hist	2369	# cat /sys/kernel/tracing/events/sched/sched_switch/hist
2216	{ next_pid: 2101 } hitcount: 200	2370	{ next_pid: 2101 } hitcount: 200
2217	max: 52 next_prio: 120 next_comm: cyclictest \	2371	max: 52 next_prio: 120 next_comm: cyclictest \
2218	prev_pid: 0 prev_prio: 120 prev_comm: swapper/6	2372	prev_pid: 0 prev_prio: 120 prev_comm: swapper/6
2219		2373
2220	{ next_pid: 2103 } hitcount: 1326	2374	{ next_pid: 2103 } hitcount: 1326
2221	max: 572 next_prio: 19 next_comm: cyclictest \	2375	max: 572 next_prio: 19 next_comm: cyclictest \
2222	prev_pid: 0 prev_prio: 120 prev_comm: swapper/1	2376	prev_pid: 0 prev_prio: 120 prev_comm: swapper/1
2223		2377
2224	{ next_pid: 2102 } hitcount: 1982 \	2378	{ next_pid: 2102 } hitcount: 1982 \
2225	max: 74 next_prio: 19 next_comm: cyclictest \	2379	max: 74 next_prio: 19 next_comm: cyclictest \
2226	prev_pid: 0 prev_prio: 120 prev_comm: swapper/5	2380	prev_pid: 0 prev_prio: 120 prev_comm: swapper/5
2227		2381
2228	Snapshot taken (see tracing/snapshot). Details:	2382	Snapshot taken (see tracing/snapshot). Details:
2229	triggering value { onmax($wakeup_lat) }: 572 \	2383	triggering value { onmax($wakeup_lat) }: 572 \
2230	triggered by event with key: { next_pid: 2103 }	2384	triggered by event with key: { next_pid: 2103 }
2231		2385
2232	Totals:	2386	Totals:
2233	Hits: 3508	2387	Hits: 3508
2234	Entries: 3	2388	Entries: 3
2235	Dropped: 0	2389	Dropped: 0
2236		2390
2237	In the above case, the event that triggered the global maximum has	2391	In the above case, the event that triggered the global maximum has
2238	the key with next_pid == 2103. If you look at the bucket that has	2392	the key with next_pid == 2103. If you look at the bucket that has
@@ -2310,15 +2464,15 @@ The following commonly-used handler.action pairs are available: · 71 unmodified lines
2310	$cwnd variable. If the value has changed, a snapshot is taken.	2464	$cwnd variable. If the value has changed, a snapshot is taken.
2311	As part of the setup, all the scheduler and tcp events are also	2465	As part of the setup, all the scheduler and tcp events are also
2312	enabled, which are the events that will show up in the snapshot	2466	enabled, which are the events that will show up in the snapshot
2313	when it is taken at some point:	2467	when it is taken at some point::
2314		2468
2315	# echo 1 > /sys/kernel/tracing/events/sched/enable	2469	# echo 1 > /sys/kernel/tracing/events/sched/enable
2316	# echo 1 > /sys/kernel/tracing/events/tcp/enable	2470	# echo 1 > /sys/kernel/tracing/events/tcp/enable
2317		2471
2318	# echo 'hist:keys=dport:cwnd=snd_cwnd: \	2472	# echo 'hist:keys=dport:cwnd=snd_cwnd: \
2319	onchange($cwnd).save(snd_wnd,srtt,rcv_wnd): \	2473	onchange($cwnd).save(snd_wnd,srtt,rcv_wnd): \
2320	onchange($cwnd).snapshot()' >> \	2474	onchange($cwnd).snapshot()' >> \
2321	/sys/kernel/tracing/events/tcp/tcp_probe/trigger	2475	/sys/kernel/tracing/events/tcp/tcp_probe/trigger
2322		2476
2323	When the histogram is displayed, for each bucket the tracked value	2477	When the histogram is displayed, for each bucket the tracked value
2324	and the saved values corresponding to that value are displayed	2478	and the saved values corresponding to that value are displayed
@@ -2341,10 +2495,10 @@ The following commonly-used handler.action pairs are available: · 16 unmodified lines
2341	{ dport: 443 } hitcount: 211	2495	{ dport: 443 } hitcount: 211
2342	changed: 10 snd_wnd: 26960 srtt: 17379 rcv_wnd: 28800	2496	changed: 10 snd_wnd: 26960 srtt: 17379 rcv_wnd: 28800
2343		2497
2344	Snapshot taken (see tracing/snapshot). Details::	2498	Snapshot taken (see tracing/snapshot). Details:
2345		2499
2346	triggering value { onchange($cwnd) }: 10	2500	triggering value { onchange($cwnd) }: 10
2347	triggered by event with key: { dport: 80 }	2501	triggered by event with key: { dport: 80 }
2348		2502
2349	Totals:	2503	Totals:
2350	Hits: 414	2504	Hits: 414

include/linux/kernel.h+1−1

@@ -297,7 +297,7 @@ bool mac_pton(const char s, u8 mac); · 296 unmodified lines
297	*	297	*
298	* Use tracing_on/tracing_off when you want to quickly turn on or off	298	* Use tracing_on/tracing_off when you want to quickly turn on or off
299	* tracing. It simply enables or disables the recording of the trace events.	299	* tracing. It simply enables or disables the recording of the trace events.
300	* This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on	300	* This also corresponds to the user space /sys/kernel/tracing/tracing_on
301	* file, which gives a means for the kernel and userspace to interact.	301	* file, which gives a means for the kernel and userspace to interact.
302	* Place a tracing_off() in the kernel where you want tracing to end.	302	* Place a tracing_off() in the kernel where you want tracing to end.
303	* From user space, examine the trace, and then echo 1 > tracing_on	303	* From user space, examine the trace, and then echo 1 > tracing_on

include/linux/trace.h+12−0

@@ -33,6 +33,18 @@ struct trace_array; · 32 unmodified lines
33	int register_ftrace_export(struct trace_export *export);	33	int register_ftrace_export(struct trace_export *export);
34	int unregister_ftrace_export(struct trace_export *export);	34	int unregister_ftrace_export(struct trace_export *export);
35		35
		36	/**
		37	* trace_array_puts - write a constant string into the trace buffer.
		38	* @tr: The trace array to write to
		39	* @str: The constant string to write
		40	*/
		41	#define trace_array_puts(tr, str) \
		42	({ \
		43	str ? __trace_array_puts(tr, _THIS_IP_, str, strlen(str)) : -1; \
		44	})
		45	int __trace_array_puts(struct trace_array *tr, unsigned long ip,
		46	const char *str, int size);
		47
36	void trace_printk_init_buffers(void);	48	void trace_printk_init_buffers(void);
37	__printf(3, 4)	49	__printf(3, 4)
38	int trace_array_printk(struct trace_array *tr, unsigned long ip,	50	int trace_array_printk(struct trace_array *tr, unsigned long ip,

include/linux/trace_seq.h+5−0

 extern int trace_seq_hex_dump(struct trace_seq *s, const char *prefix_str,
 			      int prefix_type, int rowsize, int groupsize,
 			      const void *buf, size_t len, bool ascii);
+char *trace_seq_acquire(struct trace_seq *s, unsigned int len);
 #else /* CONFIG_TRACING */
 static inline __printf(2, 3)
 {
 	return 0;
 }
+static inline char *trace_seq_acquire(struct trace_seq *s, unsigned int len)
+{
+	return NULL;
+}
 #endif /* CONFIG_TRACING */
 #endif /* _LINUX_TRACE_SEQ_H */

include/linux/tracepoint.h+2−2

@@ -482,7 +482,7 @@ static inline struct tracepoint tracepoint_ptr_deref(tracepoint_ptr_t p) · 481 unmodified lines
482	* * This is how the trace record is structured and will	482	* * This is how the trace record is structured and will
483	* * be saved into the ring buffer. These are the fields	483	* * be saved into the ring buffer. These are the fields
484	* * that will be exposed to user-space in	484	* * that will be exposed to user-space in
485	* * /sys/kernel/debug/tracing/events/<*>/format.	485	* * /sys/kernel/tracing/events/<*>/format.
486	* *	486	* *
487	* * The declared 'local variable' is called '__entry'	487	* * The declared 'local variable' is called '__entry'
488	* *	488	* *
@@ -542,7 +542,7 @@ static inline struct tracepoint tracepoint_ptr_deref(tracepoint_ptr_t p) · 53 unmodified lines
542	* tracepoint callback (this is used by programmatic plugins and	542	* tracepoint callback (this is used by programmatic plugins and
543	* can also by used by generic instrumentation like SystemTap), and	543	* can also by used by generic instrumentation like SystemTap), and
544	* it is also used to expose a structured trace record in	544	* it is also used to expose a structured trace record in
545	* /sys/kernel/debug/tracing/events/.	545	* /sys/kernel/tracing/events/.
546	*	546	*
547	* A set of (un)registration functions can be passed to the variant	547	* A set of (un)registration functions can be passed to the variant
548	* TRACE_EVENT_FN to perform any (un)registration work.	548	* TRACE_EVENT_FN to perform any (un)registration work.

include/trace/bpf_probe.h+1−44

@@ -4,50 +4,7 @@ · 3 unmodified lines
4		4
5	#ifdef CONFIG_BPF_EVENTS	5	#ifdef CONFIG_BPF_EVENTS
6		6
7	#undef __entry	7	#include "stages/stage6_event_callback.h"
8	#define __entry entry
9
10	#undef __get_dynamic_array
11	#define __get_dynamic_array(field) \
12	((void *)__entry + (__entry->__data_loc_##field & 0xffff))
13
14	#undef __get_dynamic_array_len
15	#define __get_dynamic_array_len(field) \
16	((__entry->__data_loc_##field >> 16) & 0xffff)
17
18	#undef __get_str
19	#define __get_str(field) ((char *)__get_dynamic_array(field))
20
21	#undef __get_bitmask
22	#define __get_bitmask(field) (char *)__get_dynamic_array(field)
23
24	#undef __get_cpumask
25	#define __get_cpumask(field) (char *)__get_dynamic_array(field)
26
27	#undef __get_sockaddr
28	#define __get_sockaddr(field) ((struct sockaddr *)__get_dynamic_array(field))
29
30	#undef __get_rel_dynamic_array
31	#define __get_rel_dynamic_array(field) \
32	((void *)(&__entry->__rel_loc_##field) + \
33	sizeof(__entry->__rel_loc_##field) + \
34	(__entry->__rel_loc_##field & 0xffff))
35
36	#undef __get_rel_dynamic_array_len
37	#define __get_rel_dynamic_array_len(field) \
38	((__entry->__rel_loc_##field >> 16) & 0xffff)
39
40	#undef __get_rel_str
41	#define __get_rel_str(field) ((char *)__get_rel_dynamic_array(field))
42
43	#undef __get_rel_bitmask
44	#define __get_rel_bitmask(field) (char *)__get_rel_dynamic_array(field)
45
46	#undef __get_rel_cpumask
47	#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
48
49	#undef __get_rel_sockaddr
50	#define __get_rel_sockaddr(field) ((struct sockaddr *)__get_rel_dynamic_array(field))
51		8
52	#undef __perf_count	9	#undef __perf_count
53	#define __perf_count(c) (c)	10	#define __perf_count(c) (c)

include/trace/perf.h+1−45

@@ -4,51 +4,7 @@ · 3 unmodified lines
4		4
5	#ifdef CONFIG_PERF_EVENTS	5	#ifdef CONFIG_PERF_EVENTS
6		6
7	#undef __entry	7	#include "stages/stage6_event_callback.h"
8	#define __entry entry
9
10	#undef __get_dynamic_array
11	#define __get_dynamic_array(field) \
12	((void *)__entry + (__entry->__data_loc_##field & 0xffff))
13
14	#undef __get_dynamic_array_len
15	#define __get_dynamic_array_len(field) \
16	((__entry->__data_loc_##field >> 16) & 0xffff)
17
18	#undef __get_str
19	#define __get_str(field) ((char *)__get_dynamic_array(field))
20
21	#undef __get_bitmask
22	#define __get_bitmask(field) (char *)__get_dynamic_array(field)
23
24	#undef __get_cpumask
25	#define __get_cpumask(field) (char *)__get_dynamic_array(field)
26
27	#undef __get_sockaddr
28	#define __get_sockaddr(field) ((struct sockaddr *)__get_dynamic_array(field))
29
30	#undef __get_rel_dynamic_array
31	#define __get_rel_dynamic_array(field) \
32	((void *)__entry + \
33	offsetof(typeof(*__entry), __rel_loc_##field) + \
34	sizeof(__entry->__rel_loc_##field) + \
35	(__entry->__rel_loc_##field & 0xffff))
36
37	#undef __get_rel_dynamic_array_len
38	#define __get_rel_dynamic_array_len(field) \
39	((__entry->__rel_loc_##field >> 16) & 0xffff)
40
41	#undef __get_rel_str
42	#define __get_rel_str(field) ((char *)__get_rel_dynamic_array(field))
43
44	#undef __get_rel_bitmask
45	#define __get_rel_bitmask(field) (char *)__get_rel_dynamic_array(field)
46
47	#undef __get_rel_cpumask
48	#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
49
50	#undef __get_rel_sockaddr
51	#define __get_rel_sockaddr(field) ((struct sockaddr *)__get_rel_dynamic_array(field))
52		8
53	#undef __perf_count	9	#undef __perf_count
54	#define __perf_count(c) (__count = (c))	10	#define __perf_count(c) (__count = (c))

include/trace/stages/stage3_trace_output.h+3−0

@@ -139,3 +139,6 @@ · 138 unmodified lines
139	u64 ____val = (u64)(value); \	139	u64 ____val = (u64)(value); \
140	(u32) do_div(____val, NSEC_PER_SEC); \	140	(u32) do_div(____val, NSEC_PER_SEC); \
141	})	141	})
		142
		143	#undef __get_buf
		144	#define __get_buf(len) trace_seq_acquire(p, (len))

include/trace/stages/stage6_event_callback.h+3−0

@@ -2,6 +2,9 @@ · 1 unmodified line
2		2
3	/* Stage 6 definitions for creating trace events */	3	/* Stage 6 definitions for creating trace events */
4		4
		5	/* Reuse some of the stage 3 macros */
		6	#include "stage3_trace_output.h"
		7
5	#undef __entry	8	#undef __entry
6	#define __entry entry	9	#define __entry entry
7		10

include/trace/stages/stage7_class_define.h+1−0

@@ -23,6 +23,7 @@ · 22 unmodified lines
23	#undef __get_rel_sockaddr	23	#undef __get_rel_sockaddr
24	#undef __print_array	24	#undef __print_array
25	#undef __print_hex_dump	25	#undef __print_hex_dump
		26	#undef __get_buf
26		27
27	/*	28	/*
28	* The below is not executed in the kernel. It is only what is	29	* The below is not executed in the kernel. It is only what is

kernel/trace/Kconfig+10−10

@@ -242,7 +242,7 @@ config DYNAMIC_FTRACE · 241 unmodified lines
242	enabled, and the functions not enabled will not affect	242	enabled, and the functions not enabled will not affect
243	performance of the system.	243	performance of the system.
244		244
245	See the files in /sys/kernel/debug/tracing:	245	See the files in /sys/kernel/tracing:
246	available_filter_functions	246	available_filter_functions
247	set_ftrace_filter	247	set_ftrace_filter
248	set_ftrace_notrace	248	set_ftrace_notrace
@@ -306,7 +306,7 @@ config STACK_TRACER · 57 unmodified lines
306	select KALLSYMS	306	select KALLSYMS
307	help	307	help
308	This special tracer records the maximum stack footprint of the	308	This special tracer records the maximum stack footprint of the
309	kernel and displays it in /sys/kernel/debug/tracing/stack_trace.	309	kernel and displays it in /sys/kernel/tracing/stack_trace.
310		310
311	This tracer works by hooking into every function call that the	311	This tracer works by hooking into every function call that the
312	kernel executes, and keeping a maximum stack depth value and	312	kernel executes, and keeping a maximum stack depth value and
@@ -346,7 +346,7 @@ config IRQSOFF_TRACER · 33 unmodified lines
346	disabled by default and can be runtime (re-)started	346	disabled by default and can be runtime (re-)started
347	via:	347	via:
348		348
349	echo 0 > /sys/kernel/debug/tracing/tracing_max_latency	349	echo 0 > /sys/kernel/tracing/tracing_max_latency
350		350
351	(Note that kernel size and overhead increase with this option	351	(Note that kernel size and overhead increase with this option
352	enabled. This option and the preempt-off timing option can be	352	enabled. This option and the preempt-off timing option can be
@@ -370,7 +370,7 @@ config PREEMPT_TRACER · 17 unmodified lines
370	disabled by default and can be runtime (re-)started	370	disabled by default and can be runtime (re-)started
371	via:	371	via:
372		372
373	echo 0 > /sys/kernel/debug/tracing/tracing_max_latency	373	echo 0 > /sys/kernel/tracing/tracing_max_latency
374		374
375	(Note that kernel size and overhead increase with this option	375	(Note that kernel size and overhead increase with this option
376	enabled. This option and the irqs-off timing option can be	376	enabled. This option and the irqs-off timing option can be
@@ -522,7 +522,7 @@ config TRACER_SNAPSHOT · 145 unmodified lines
522	Allow tracing users to take snapshot of the current buffer using the	522	Allow tracing users to take snapshot of the current buffer using the
523	ftrace interface, e.g.:	523	ftrace interface, e.g.:
524		524
525	echo 1 > /sys/kernel/debug/tracing/snapshot	525	echo 1 > /sys/kernel/tracing/snapshot
526	cat snapshot	526	cat snapshot
527		527
528	config TRACER_SNAPSHOT_PER_CPU_SWAP	528	config TRACER_SNAPSHOT_PER_CPU_SWAP
@@ -534,7 +534,7 @@ config TRACER_SNAPSHOT_PER_CPU_SWAP · 5 unmodified lines
534	full swap (all buffers). If this is set, then the following is	534	full swap (all buffers). If this is set, then the following is
535	allowed:	535	allowed:
536		536
537	echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot	537	echo 1 > /sys/kernel/tracing/per_cpu/cpu2/snapshot
538		538
539	After which, only the tracing buffer for CPU 2 was swapped with	539	After which, only the tracing buffer for CPU 2 was swapped with
540	the main tracing buffer, and the other CPU buffers remain the same.	540	the main tracing buffer, and the other CPU buffers remain the same.
@@ -581,7 +581,7 @@ config PROFILE_ANNOTATED_BRANCHES · 40 unmodified lines
581	This tracer profiles all likely and unlikely macros	581	This tracer profiles all likely and unlikely macros
582	in the kernel. It will display the results in:	582	in the kernel. It will display the results in:
583		583
584	/sys/kernel/debug/tracing/trace_stat/branch_annotated	584	/sys/kernel/tracing/trace_stat/branch_annotated
585		585
586	Note: this will add a significant overhead; only turn this	586	Note: this will add a significant overhead; only turn this
587	on if you need to profile the system's use of these macros.	587	on if you need to profile the system's use of these macros.
@@ -594,7 +594,7 @@ config PROFILE_ALL_BRANCHES · 6 unmodified lines
594	taken in the kernel is recorded whether it hit or miss.	594	taken in the kernel is recorded whether it hit or miss.
595	The results will be displayed in:	595	The results will be displayed in:
596		596
597	/sys/kernel/debug/tracing/trace_stat/branch_all	597	/sys/kernel/tracing/trace_stat/branch_all
598		598
599	This option also enables the likely/unlikely profiler.	599	This option also enables the likely/unlikely profiler.
600		600
@@ -645,8 +645,8 @@ config BLK_DEV_IO_TRACE · 44 unmodified lines
645	Tracing also is possible using the ftrace interface, e.g.:	645	Tracing also is possible using the ftrace interface, e.g.:
646		646
647	echo 1 > /sys/block/sda/sda1/trace/enable	647	echo 1 > /sys/block/sda/sda1/trace/enable
648	echo blk > /sys/kernel/debug/tracing/current_tracer	648	echo blk > /sys/kernel/tracing/current_tracer
649	cat /sys/kernel/debug/tracing/trace_pipe	649	cat /sys/kernel/tracing/trace_pipe
650		650
651	If unsure, say N.	651	If unsure, say N.
652		652

kernel/trace/kprobe_event_gen_test.c+1−1

@@ -21,7 +21,7 @@ · 20 unmodified lines
21	* Then:	21	* Then:
22	*	22	*
23	* # insmod kernel/trace/kprobe_event_gen_test.ko	23	* # insmod kernel/trace/kprobe_event_gen_test.ko
24	* # cat /sys/kernel/debug/tracing/trace	24	* # cat /sys/kernel/tracing/trace
25	*	25	*
26	* You should see many instances of the "gen_kprobe_test" and	26	* You should see many instances of the "gen_kprobe_test" and
27	* "gen_kretprobe_test" events in the trace buffer.	27	* "gen_kretprobe_test" events in the trace buffer.

kernel/trace/ring_buffer.c+7−2

 		  sched_clock_stable() ? "" :
 		  "If you just came from a suspend/resume,\n"
 		  "please switch to the trace global clock:\n"
-		  "  echo global > /sys/kernel/debug/tracing/trace_clock\n"
+		  "  echo global > /sys/kernel/tracing/trace_clock\n"
 		  "or add trace_clock=global to the kernel command line\n");
 }
  */
 void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu, void *data)
 {
-	struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
+	struct ring_buffer_per_cpu *cpu_buffer;
 	struct buffer_data_page *bpage = data;
 	struct page *page = virt_to_page(bpage);
 	unsigned long flags;
+	if (!buffer || !buffer->buffers || !buffer->buffers[cpu])
+		return;
+	cpu_buffer = buffer->buffers[cpu];
 	/* If the page is still in use someplace else, we can't reuse it */
 	if (page_ref_count(page) > 1)
 		goto out;

kernel/trace/synth_event_gen_test.c+1−1

@@ -22,7 +22,7 @@ · 21 unmodified lines
22	* Then:	22	* Then:
23	*	23	*
24	* # insmod kernel/trace/synth_event_gen_test.ko	24	* # insmod kernel/trace/synth_event_gen_test.ko
25	* # cat /sys/kernel/debug/tracing/trace	25	* # cat /sys/kernel/tracing/trace
26	*	26	*
27	* You should see several events in the trace buffer -	27	* You should see several events in the trace buffer -
28	* "create_synth_test", "empty_synth_test", and several instances of	28	* "create_synth_test", "empty_synth_test", and several instances of

kernel/trace/trace.c+145−19

@@ -49,6 +49,8 @@ · 48 unmodified lines
49	#include <linux/irq_work.h>	49	#include <linux/irq_work.h>
50	#include <linux/workqueue.h>	50	#include <linux/workqueue.h>
51		51
		52	#include <asm/setup.h> /* COMMAND_LINE_SIZE */
		53
52	#include "trace.h"	54	#include "trace.h"
53	#include "trace_output.h"	55	#include "trace_output.h"
54		56
@@ -186,6 +188,12 @@ static char *default_bootup_tracer; · 131 unmodified lines
186	static bool allocate_snapshot;	188	static bool allocate_snapshot;
187	static bool snapshot_at_boot;	189	static bool snapshot_at_boot;
188		190
		191	static char boot_instance_info[COMMAND_LINE_SIZE] __initdata;
		192	static int boot_instance_index;
		193
		194	static char boot_snapshot_info[COMMAND_LINE_SIZE] __initdata;
		195	static int boot_snapshot_index;
		196
189	static int __init set_cmdline_ftrace(char *str)	197	static int __init set_cmdline_ftrace(char *str)
190	{	198	{
191	strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);	199	strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
@@ -222,9 +230,22 @@ __setup("traceoff_on_warning", stop_trace_on_warning); · 30 unmodified lines
222		230
223	static int __init boot_alloc_snapshot(char *str)	231	static int __init boot_alloc_snapshot(char *str)
224	{	232	{
225	allocate_snapshot = true;	233	char *slot = boot_snapshot_info + boot_snapshot_index;
226	/* We also need the main ring buffer expanded */	234	int left = sizeof(boot_snapshot_info) - boot_snapshot_index;
227	ring_buffer_expanded = true;	235	int ret;
		236
		237	if (str[0] == '=') {
		238	str++;
		239	if (strlen(str) >= left)
		240	return -1;
		241
		242	ret = snprintf(slot, left, "%s\t", str);
		243	boot_snapshot_index += ret;
		244	} else {
		245	allocate_snapshot = true;
		246	/* We also need the main ring buffer expanded */
		247	ring_buffer_expanded = true;
		248	}
228	return 1;	249	return 1;
229	}	250	}
230	__setup("alloc_snapshot", boot_alloc_snapshot);	251	__setup("alloc_snapshot", boot_alloc_snapshot);
@@ -239,6 +260,23 @@ static int __init boot_snapshot(char *str) · 8 unmodified lines
239	__setup("ftrace_boot_snapshot", boot_snapshot);	260	__setup("ftrace_boot_snapshot", boot_snapshot);
240		261
241		262
		263	static int __init boot_instance(char *str)
		264	{
		265	char *slot = boot_instance_info + boot_instance_index;
		266	int left = sizeof(boot_instance_info) - boot_instance_index;
		267	int ret;
		268
		269	if (strlen(str) >= left)
		270	return -1;
		271
		272	ret = snprintf(slot, left, "%s\t", str);
		273	boot_instance_index += ret;
		274
		275	return 1;
		276	}
		277	__setup("trace_instance=", boot_instance);
		278
		279
242	static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;	280	static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
243		281
244	static int __init set_trace_boot_options(char *str)	282	static int __init set_trace_boot_options(char *str)
@@ -1001,13 +1039,8 @@ __buffer_unlock_commit(struct trace_buffer buffer, struct ring_buffer_event ev · 756 unmodified lines
1001	ring_buffer_unlock_commit(buffer);	1039	ring_buffer_unlock_commit(buffer);
1002	}	1040	}
1003		1041
1004	/**	1042	int __trace_array_puts(struct trace_array *tr, unsigned long ip,
1005	* __trace_puts - write a constant string into the trace buffer.	1043	const char *str, int size)
1006	* @ip: The address of the caller
1007	* @str: The constant string to write
1008	* @size: The size of the string.
1009	*/
1010	int __trace_puts(unsigned long ip, const char *str, int size)
1011	{	1044	{
1012	struct ring_buffer_event *event;	1045	struct ring_buffer_event *event;
1013	struct trace_buffer *buffer;	1046	struct trace_buffer *buffer;
@@ -1015,7 +1048,7 @@ int __trace_puts(unsigned long ip, const char *str, int size) · 1 unmodified line
1015	unsigned int trace_ctx;	1048	unsigned int trace_ctx;
1016	int alloc;	1049	int alloc;
1017		1050
1018	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))	1051	if (!(tr->trace_flags & TRACE_ITER_PRINTK))
1019	return 0;	1052	return 0;
1020		1053
1021	if (unlikely(tracing_selftest_running \|\| tracing_disabled))	1054	if (unlikely(tracing_selftest_running \|\| tracing_disabled))
@@ -1024,7 +1057,7 @@ int __trace_puts(unsigned long ip, const char *str, int size) · 2 unmodified lines
1024	alloc = sizeof(entry) + size + 2; / possible \n added */	1057	alloc = sizeof(entry) + size + 2; / possible \n added */
1025		1058
1026	trace_ctx = tracing_gen_ctx();	1059	trace_ctx = tracing_gen_ctx();
1027	buffer = global_trace.array_buffer.buffer;	1060	buffer = tr->array_buffer.buffer;
1028	ring_buffer_nest_start(buffer);	1061	ring_buffer_nest_start(buffer);
1029	event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,	1062	event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
1030	trace_ctx);	1063	trace_ctx);
@@ -1046,11 +1079,23 @@ int __trace_puts(unsigned long ip, const char *str, int size) · 15 unmodified lines
1046	entry->buf[size] = '\0';	1079	entry->buf[size] = '\0';
1047		1080
1048	__buffer_unlock_commit(buffer, event);	1081	__buffer_unlock_commit(buffer, event);
1049	ftrace_trace_stack(&global_trace, buffer, trace_ctx, 4, NULL);	1082	ftrace_trace_stack(tr, buffer, trace_ctx, 4, NULL);
1050	out:	1083	out:
1051	ring_buffer_nest_end(buffer);	1084	ring_buffer_nest_end(buffer);
1052	return size;	1085	return size;
1053	}	1086	}
		1087	EXPORT_SYMBOL_GPL(__trace_array_puts);
		1088
		1089	/**
		1090	* __trace_puts - write a constant string into the trace buffer.
		1091	* @ip: The address of the caller
		1092	* @str: The constant string to write
		1093	* @size: The size of the string.
		1094	*/
		1095	int __trace_puts(unsigned long ip, const char *str, int size)
		1096	{
		1097	return __trace_array_puts(&global_trace, ip, str, size);
		1098	}
1054	EXPORT_SYMBOL_GPL(__trace_puts);	1099	EXPORT_SYMBOL_GPL(__trace_puts);
1055		1100
1056	/**	1101	/**
@@ -1142,7 +1187,7 @@ void tracing_snapshot_instance(struct trace_array *tr) · 85 unmodified lines
1142	*	1187	*
1143	* Note, make sure to allocate the snapshot with either	1188	* Note, make sure to allocate the snapshot with either
1144	* a tracing_snapshot_alloc(), or by doing it manually	1189	* a tracing_snapshot_alloc(), or by doing it manually
1145	* with: echo 1 > /sys/kernel/debug/tracing/snapshot	1190	* with: echo 1 > /sys/kernel/tracing/snapshot
1146	*	1191	*
1147	* If the snapshot buffer is not allocated, it will stop tracing.	1192	* If the snapshot buffer is not allocated, it will stop tracing.
1148	* Basically making a permanent snapshot.	1193	* Basically making a permanent snapshot.
@@ -5760,7 +5805,7 @@ static const char readme_msg[] = · 4611 unmodified lines
5760	#ifdef CONFIG_SYNTH_EVENTS	5805	#ifdef CONFIG_SYNTH_EVENTS
5761	" events/synthetic_events\t- Create/append/remove/show synthetic events\n"	5806	" events/synthetic_events\t- Create/append/remove/show synthetic events\n"
5762	"\t Write into this file to define/undefine new synthetic events.\n"	5807	"\t Write into this file to define/undefine new synthetic events.\n"
5763	"\t example: echo 'myevent u64 lat; char name[]' >> synthetic_events\n"	5808	"\t example: echo 'myevent u64 lat; char name[]; long[] stack' >> synthetic_events\n"
5764	#endif	5809	#endif
5765	#endif	5810	#endif
5766	;	5811	;
@@ -9225,10 +9270,6 @@ static int allocate_trace_buffers(struct trace_array *tr, int size) · 3458 unmodified lines
9225	}	9270	}
9226	tr->allocated_snapshot = allocate_snapshot;	9271	tr->allocated_snapshot = allocate_snapshot;
9227		9272
9228	/*
9229	* Only the top level trace array gets its snapshot allocated
9230	* from the kernel command line.
9231	*/
9232	allocate_snapshot = false;	9273	allocate_snapshot = false;
9233	#endif	9274	#endif
9234		9275
@@ -10144,6 +10185,79 @@ out: · 909 unmodified lines
10144	return ret;	10185	return ret;
10145	}	10186	}
10146		10187
		10188	#ifdef CONFIG_TRACER_MAX_TRACE
		10189	__init static bool tr_needs_alloc_snapshot(const char *name)
		10190	{
		10191	char *test;
		10192	int len = strlen(name);
		10193	bool ret;
		10194
		10195	if (!boot_snapshot_index)
		10196	return false;
		10197
		10198	if (strncmp(name, boot_snapshot_info, len) == 0 &&
		10199	boot_snapshot_info[len] == '\t')
		10200	return true;
		10201
		10202	test = kmalloc(strlen(name) + 3, GFP_KERNEL);
		10203	if (!test)
		10204	return false;
		10205
		10206	sprintf(test, "\t%s\t", name);
		10207	ret = strstr(boot_snapshot_info, test) == NULL;
		10208	kfree(test);
		10209	return ret;
		10210	}
		10211
		10212	__init static void do_allocate_snapshot(const char *name)
		10213	{
		10214	if (!tr_needs_alloc_snapshot(name))
		10215	return;
		10216
		10217	/*
		10218	* When allocate_snapshot is set, the next call to
		10219	* allocate_trace_buffers() (called by trace_array_get_by_name())
		10220	* will allocate the snapshot buffer. That will alse clear
		10221	* this flag.
		10222	*/
		10223	allocate_snapshot = true;
		10224	}
		10225	#else
		10226	static inline void do_allocate_snapshot(const char *name) { }
		10227	#endif
		10228
		10229	__init static void enable_instances(void)
		10230	{
		10231	struct trace_array *tr;
		10232	char *curr_str;
		10233	char *str;
		10234	char *tok;
		10235
		10236	/* A tab is always appended */
		10237	boot_instance_info[boot_instance_index - 1] = '\0';
		10238	str = boot_instance_info;
		10239
		10240	while ((curr_str = strsep(&str, "\t"))) {
		10241
		10242	tok = strsep(&curr_str, ",");
		10243
		10244	if (IS_ENABLED(CONFIG_TRACER_MAX_TRACE))
		10245	do_allocate_snapshot(tok);
		10246
		10247	tr = trace_array_get_by_name(tok);
		10248	if (!tr) {
		10249	pr_warn("Failed to create instance buffer %s\n", curr_str);
		10250	continue;
		10251	}
		10252	/* Allow user space to delete it */
		10253	trace_array_put(tr);
		10254
		10255	while ((tok = strsep(&curr_str, ","))) {
		10256	early_enable_events(tr, tok, true);
		10257	}
		10258	}
		10259	}
		10260
10147	__init static int tracer_alloc_buffers(void)	10261	__init static int tracer_alloc_buffers(void)
10148	{	10262	{
10149	int ring_buf_size;	10263	int ring_buf_size;
@@ -10277,10 +10391,19 @@ out: · 127 unmodified lines
10277		10391
10278	void __init ftrace_boot_snapshot(void)	10392	void __init ftrace_boot_snapshot(void)
10279	{	10393	{
		10394	struct trace_array *tr;
		10395
10280	if (snapshot_at_boot) {	10396	if (snapshot_at_boot) {
10281	tracing_snapshot();	10397	tracing_snapshot();
10282	internal_trace_puts(" Boot snapshot taken \n");	10398	internal_trace_puts(" Boot snapshot taken \n");
10283	}	10399	}
		10400
		10401	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
		10402	if (tr == &global_trace)
		10403	continue;
		10404	trace_array_puts(tr, " Boot snapshot taken \n");
		10405	tracing_snapshot_instance(tr);
		10406	}
10284	}	10407	}
10285		10408
10286	void __init early_trace_init(void)	10409	void __init early_trace_init(void)
@@ -10302,6 +10425,9 @@ void __init early_trace_init(void) · 15 unmodified lines
10302	void __init trace_init(void)	10425	void __init trace_init(void)
10303	{	10426	{
10304	trace_event_init();	10427	trace_event_init();
		10428
		10429	if (boot_instance_index)
		10430	enable_instances();
10305	}	10431	}
10306		10432
10307	__init static void clear_boot_tracer(void)	10433	__init static void clear_boot_tracer(void)

kernel/trace/trace.h+6−0

 #define MEM_FAIL(condition, fmt, ...)					\
 	DO_ONCE_LITE_IF(condition, pr_err, "ERROR: " fmt, ##__VA_ARGS__)
+#define HIST_STACKTRACE_DEPTH	16
+#define HIST_STACKTRACE_SIZE	(HIST_STACKTRACE_DEPTH * sizeof(unsigned long))
+#define HIST_STACKTRACE_SKIP	5
 /*
  * syscalls are special, and need special handling, this is why
  * they are not included in trace_entries.h
 void trace_buffered_event_disable(void);
 void trace_buffered_event_enable(void);
+void early_enable_events(struct trace_array *tr, char *buf, bool disable_first);
 static inline void
 __trace_event_discard_commit(struct trace_buffer *buffer,
 			     struct ring_buffer_event *event)

kernel/trace/trace_events.c+5−8

 	if (!system->name)
 		goto out_free;
-	system->filter = NULL;
 	system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
 	if (!system->filter)
 		goto out_free;
 		if (!trigger)
 			break;
 		bootup_triggers[i].event = strsep(&trigger, ".");
-		bootup_triggers[i].trigger = strsep(&trigger, ".");
+		bootup_triggers[i].trigger = trigger;
 		if (!bootup_triggers[i].trigger)
 			break;
 	}
 	return 0;
 }
-static __init void
+__init void
-early_enable_events(struct trace_array *tr, bool disable_first)
+early_enable_events(struct trace_array *tr, char *buf, bool disable_first)
 {
-	char *buf = bootup_event_buf;
 	char *token;
 	int ret;
 	 */
 	__trace_early_add_events(tr);
-	early_enable_events(tr, false);
+	early_enable_events(tr, bootup_event_buf, false);
 	trace_printk_start_comm();
 	if (!tr)
 		return -ENODEV;
-	early_enable_events(tr, true);
+	early_enable_events(tr, bootup_event_buf, true);
 	return 0;
 }

kernel/trace/trace_events_filter.c+92−1

@@ -64,6 +64,7 @@ enum filter_pred_fn { · 63 unmodified lines
64	FILTER_PRED_FN_PCHAR_USER,	64	FILTER_PRED_FN_PCHAR_USER,
65	FILTER_PRED_FN_PCHAR,	65	FILTER_PRED_FN_PCHAR,
66	FILTER_PRED_FN_CPU,	66	FILTER_PRED_FN_CPU,
		67	FILTER_PRED_FN_FUNCTION,
67	FILTER_PRED_FN_,	68	FILTER_PRED_FN_,
68	FILTER_PRED_TEST_VISITED,	69	FILTER_PRED_TEST_VISITED,
69	};	70	};
@@ -71,6 +72,7 @@ enum filter_pred_fn { · 1 unmodified line
71	struct filter_pred {	72	struct filter_pred {
72	enum filter_pred_fn fn_num;	73	enum filter_pred_fn fn_num;
73	u64 val;	74	u64 val;
		75	u64 val2;
74	struct regex regex;	76	struct regex regex;
75	unsigned short *ops;	77	unsigned short *ops;
76	struct ftrace_event_field *field;	78	struct ftrace_event_field *field;
@@ -103,6 +105,7 @@ struct filter_pred { · 26 unmodified lines
103	C(INVALID_FILTER, "Meaningless filter expression"), \	105	C(INVALID_FILTER, "Meaningless filter expression"), \
104	C(IP_FIELD_ONLY, "Only 'ip' field is supported for function trace"), \	106	C(IP_FIELD_ONLY, "Only 'ip' field is supported for function trace"), \
105	C(INVALID_VALUE, "Invalid value (did you forget quotes)?"), \	107	C(INVALID_VALUE, "Invalid value (did you forget quotes)?"), \
		108	C(NO_FUNCTION, "Function not found"), \
106	C(ERRNO, "Error"), \	109	C(ERRNO, "Error"), \
107	C(NO_FILTER, "No filter found")	110	C(NO_FILTER, "No filter found")
108		111
@@ -876,6 +879,17 @@ static int filter_pred_comm(struct filter_pred pred, void event) · 767 unmodified lines
876	return cmp ^ pred->not;	879	return cmp ^ pred->not;
877	}	880	}
878		881
		882	/* Filter predicate for functions. */
		883	static int filter_pred_function(struct filter_pred pred, void event)
		884	{
		885	unsigned long addr = (unsigned long )(event + pred->offset);
		886	unsigned long start = (unsigned long)pred->val;
		887	unsigned long end = (unsigned long)pred->val2;
		888	int ret = addr >= start && addr < end;
		889
		890	return pred->op == OP_EQ ? ret : !ret;
		891	}
		892
879	/*	893	/*
880	* regex_match_foo - Basic regex callbacks	894	* regex_match_foo - Basic regex callbacks
881	*	895	*
@@ -1335,6 +1349,8 @@ static int filter_pred_fn_call(struct filter_pred pred, void event) · 453 unmodified lines
1335	return filter_pred_pchar(pred, event);	1349	return filter_pred_pchar(pred, event);
1336	case FILTER_PRED_FN_CPU:	1350	case FILTER_PRED_FN_CPU:
1337	return filter_pred_cpu(pred, event);	1351	return filter_pred_cpu(pred, event);
		1352	case FILTER_PRED_FN_FUNCTION:
		1353	return filter_pred_function(pred, event);
1338	case FILTER_PRED_TEST_VISITED:	1354	case FILTER_PRED_TEST_VISITED:
1339	return test_pred_visited_fn(pred, event);	1355	return test_pred_visited_fn(pred, event);
1340	default:	1356	default:
@@ -1350,8 +1366,13 @@ static int parse_pred(const char str, void data, · 9 unmodified lines
1350	struct trace_event_call *call = data;	1366	struct trace_event_call *call = data;
1351	struct ftrace_event_field *field;	1367	struct ftrace_event_field *field;
1352	struct filter_pred *pred = NULL;	1368	struct filter_pred *pred = NULL;
		1369	unsigned long offset;
		1370	unsigned long size;
		1371	unsigned long ip;
1353	char num_buf[24]; /* Big enough to hold an address */	1372	char num_buf[24]; /* Big enough to hold an address */
1354	char *field_name;	1373	char *field_name;
		1374	char *name;
		1375	bool function = false;
1355	bool ustring = false;	1376	bool ustring = false;
1356	char q;	1377	char q;
1357	u64 val;	1378	u64 val;
@@ -1393,6 +1414,12 @@ static int parse_pred(const char str, void data, · 35 unmodified lines
1393	i += len;	1414	i += len;
1394	}	1415	}
1395		1416
		1417	/* See if the field is a kernel function name */
		1418	if ((len = str_has_prefix(str + i, ".function"))) {
		1419	function = true;
		1420	i += len;
		1421	}
		1422
1396	while (isspace(str[i]))	1423	while (isspace(str[i]))
1397	i++;	1424	i++;
1398		1425
@@ -1423,7 +1450,71 @@ static int parse_pred(const char str, void data, · 24 unmodified lines
1423	pred->offset = field->offset;	1450	pred->offset = field->offset;
1424	pred->op = op;	1451	pred->op = op;
1425		1452
1426	if (ftrace_event_is_function(call)) {	1453	if (function) {
		1454	/* The field must be the same size as long */
		1455	if (field->size != sizeof(long)) {
		1456	parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, pos + i);
		1457	goto err_free;
		1458	}
		1459
		1460	/* Function only works with '==' or '!=' and an unquoted string */
		1461	switch (op) {
		1462	case OP_NE:
		1463	case OP_EQ:
		1464	break;
		1465	default:
		1466	parse_error(pe, FILT_ERR_INVALID_OP, pos + i);
		1467	goto err_free;
		1468	}
		1469
		1470	if (isdigit(str[i])) {
		1471	/* We allow 0xDEADBEEF */
		1472	while (isalnum(str[i]))
		1473	i++;
		1474
		1475	len = i - s;
		1476	/* 0xfeedfacedeadbeef is 18 chars max */
		1477	if (len >= sizeof(num_buf)) {
		1478	parse_error(pe, FILT_ERR_OPERAND_TOO_LONG, pos + i);
		1479	goto err_free;
		1480	}
		1481
		1482	strncpy(num_buf, str + s, len);
		1483	num_buf[len] = 0;
		1484
		1485	ret = kstrtoul(num_buf, 0, &ip);
		1486	if (ret) {
		1487	parse_error(pe, FILT_ERR_INVALID_VALUE, pos + i);
		1488	goto err_free;
		1489	}
		1490	} else {
		1491	s = i;
		1492	for (; str[i] && !isspace(str[i]); i++)
		1493	;
		1494
		1495	len = i - s;
		1496	name = kmemdup_nul(str + s, len, GFP_KERNEL);
		1497	if (!name)
		1498	goto err_mem;
		1499	ip = kallsyms_lookup_name(name);
		1500	kfree(name);
		1501	if (!ip) {
		1502	parse_error(pe, FILT_ERR_NO_FUNCTION, pos + i);
		1503	goto err_free;
		1504	}
		1505	}
		1506
		1507	/* Now find the function start and end address */
		1508	if (!kallsyms_lookup_size_offset(ip, &size, &offset)) {
		1509	parse_error(pe, FILT_ERR_NO_FUNCTION, pos + i);
		1510	goto err_free;
		1511	}
		1512
		1513	pred->fn_num = FILTER_PRED_FN_FUNCTION;
		1514	pred->val = ip - offset;
		1515	pred->val2 = pred->val + size;
		1516
		1517	} else if (ftrace_event_is_function(call)) {
1427	/*	1518	/*
1428	* Perf does things different with function events.	1519	* Perf does things different with function events.
1429	* It only allows an "ip" field, and expects a string.	1520	* It only allows an "ip" field, and expects a string.

kernel/trace/trace_events_hist.c+103−23

@@ -135,6 +135,7 @@ enum hist_field_fn { · 134 unmodified lines
135	HIST_FIELD_FN_DIV_NOT_POWER2,	135	HIST_FIELD_FN_DIV_NOT_POWER2,
136	HIST_FIELD_FN_DIV_MULT_SHIFT,	136	HIST_FIELD_FN_DIV_MULT_SHIFT,
137	HIST_FIELD_FN_EXECNAME,	137	HIST_FIELD_FN_EXECNAME,
		138	HIST_FIELD_FN_STACK,
138	};	139	};
139		140
140	/*	141	/*
@@ -480,10 +481,6 @@ DEFINE_HIST_FIELD_FN(u8); · 339 unmodified lines
480	#define for_each_hist_key_field(i, hist_data) \	481	#define for_each_hist_key_field(i, hist_data) \
481	for ((i) = (hist_data)->n_vals; (i) < (hist_data)->n_fields; (i)++)	482	for ((i) = (hist_data)->n_vals; (i) < (hist_data)->n_fields; (i)++)
482		483
483	#define HIST_STACKTRACE_DEPTH 16
484	#define HIST_STACKTRACE_SIZE (HIST_STACKTRACE_DEPTH * sizeof(unsigned long))
485	#define HIST_STACKTRACE_SKIP 5
486
487	#define HITCOUNT_IDX 0	484	#define HITCOUNT_IDX 0
488	#define HIST_KEY_SIZE_MAX (MAX_FILTER_STR_VAL + HIST_STACKTRACE_SIZE)	485	#define HIST_KEY_SIZE_MAX (MAX_FILTER_STR_VAL + HIST_STACKTRACE_SIZE)
489		486
@@ -1360,7 +1357,12 @@ static const char hist_field_name(struct hist_field field, · 870 unmodified lines
1360	field_name = field->name;	1357	field_name = field->name;
1361	} else if (field->flags & HIST_FIELD_FL_TIMESTAMP)	1358	} else if (field->flags & HIST_FIELD_FL_TIMESTAMP)
1362	field_name = "common_timestamp";	1359	field_name = "common_timestamp";
1363	else if (field->flags & HIST_FIELD_FL_HITCOUNT)	1360	else if (field->flags & HIST_FIELD_FL_STACKTRACE) {
		1361	if (field->field)
		1362	field_name = field->field->name;
		1363	else
		1364	field_name = "stacktrace";
		1365	} else if (field->flags & HIST_FIELD_FL_HITCOUNT)
1364	field_name = "hitcount";	1366	field_name = "hitcount";
1365		1367
1366	if (field_name == NULL)	1368	if (field_name == NULL)
@@ -1718,6 +1720,8 @@ static const char get_hist_field_flags(struct hist_field hist_field) · 351 unmodified lines
1718	flags_str = "percent";	1720	flags_str = "percent";
1719	else if (hist_field->flags & HIST_FIELD_FL_GRAPH)	1721	else if (hist_field->flags & HIST_FIELD_FL_GRAPH)
1720	flags_str = "graph";	1722	flags_str = "graph";
		1723	else if (hist_field->flags & HIST_FIELD_FL_STACKTRACE)
		1724	flags_str = "stacktrace";
1721		1725
1722	return flags_str;	1726	return flags_str;
1723	}	1727	}
@@ -1979,7 +1983,14 @@ static struct hist_field create_hist_field(struct hist_trigger_data hist_data, · 255 unmodified lines
1979	}	1983	}
1980		1984
1981	if (flags & HIST_FIELD_FL_STACKTRACE) {	1985	if (flags & HIST_FIELD_FL_STACKTRACE) {
1982	hist_field->fn_num = HIST_FIELD_FN_NOP;	1986	if (field)
		1987	hist_field->fn_num = HIST_FIELD_FN_STACK;
		1988	else
		1989	hist_field->fn_num = HIST_FIELD_FN_NOP;
		1990	hist_field->size = HIST_STACKTRACE_SIZE;
		1991	hist_field->type = kstrdup_const("unsigned long[]", GFP_KERNEL);
		1992	if (!hist_field->type)
		1993	goto free;
1983	goto out;	1994	goto out;
1984	}	1995	}
1985		1996
@@ -2312,6 +2323,8 @@ parse_field(struct hist_trigger_data hist_data, struct trace_event_file file, · 326 unmodified lines
2312	*flags \|= HIST_FIELD_FL_EXECNAME;	2323	*flags \|= HIST_FIELD_FL_EXECNAME;
2313	else if (strcmp(modifier, "syscall") == 0)	2324	else if (strcmp(modifier, "syscall") == 0)
2314	*flags \|= HIST_FIELD_FL_SYSCALL;	2325	*flags \|= HIST_FIELD_FL_SYSCALL;
		2326	else if (strcmp(modifier, "stacktrace") == 0)
		2327	*flags \|= HIST_FIELD_FL_STACKTRACE;
2315	else if (strcmp(modifier, "log2") == 0)	2328	else if (strcmp(modifier, "log2") == 0)
2316	*flags \|= HIST_FIELD_FL_LOG2;	2329	*flags \|= HIST_FIELD_FL_LOG2;
2317	else if (strcmp(modifier, "usecs") == 0)	2330	else if (strcmp(modifier, "usecs") == 0)
@@ -2351,6 +2364,8 @@ parse_field(struct hist_trigger_data hist_data, struct trace_event_file file, · 33 unmodified lines
2351	hist_data->enable_timestamps = true;	2364	hist_data->enable_timestamps = true;
2352	if (*flags & HIST_FIELD_FL_TIMESTAMP_USECS)	2365	if (*flags & HIST_FIELD_FL_TIMESTAMP_USECS)
2353	hist_data->attrs->ts_in_usecs = true;	2366	hist_data->attrs->ts_in_usecs = true;
		2367	} else if (strcmp(field_name, "stacktrace") == 0) {
		2368	*flags \|= HIST_FIELD_FL_STACKTRACE;
2354	} else if (strcmp(field_name, "common_cpu") == 0)	2369	} else if (strcmp(field_name, "common_cpu") == 0)
2355	*flags \|= HIST_FIELD_FL_CPU;	2370	*flags \|= HIST_FIELD_FL_CPU;
2356	else if (strcmp(field_name, "hitcount") == 0)	2371	else if (strcmp(field_name, "hitcount") == 0)
@@ -3111,6 +3126,9 @@ static inline void __update_field_vars(struct tracing_map_elt *elt, · 754 unmodified lines
3111	unsigned int i, j, var_idx;	3126	unsigned int i, j, var_idx;
3112	u64 var_val;	3127	u64 var_val;
3113		3128
		3129	/* Make sure stacktrace can fit in the string variable length */
		3130	BUILD_BUG_ON((HIST_STACKTRACE_DEPTH + 1) * sizeof(long) >= STR_VAR_LEN_MAX);
		3131
3114	for (i = 0, j = field_var_str_start; i < n_field_vars; i++) {	3132	for (i = 0, j = field_var_str_start; i < n_field_vars; i++) {
3115	struct field_var *field_var = field_vars[i];	3133	struct field_var *field_var = field_vars[i];
3116	struct hist_field *var = field_var->var;	3134	struct hist_field *var = field_var->var;
@@ -3119,13 +3137,26 @@ static inline void __update_field_vars(struct tracing_map_elt *elt, · 2 unmodified lines
3119	var_val = hist_fn_call(val, elt, buffer, rbe, rec);	3137	var_val = hist_fn_call(val, elt, buffer, rbe, rec);
3120	var_idx = var->var.idx;	3138	var_idx = var->var.idx;
3121		3139
3122	if (val->flags & HIST_FIELD_FL_STRING) {	3140	if (val->flags & (HIST_FIELD_FL_STRING \|
		3141	HIST_FIELD_FL_STACKTRACE)) {
3123	char *str = elt_data->field_var_str[j++];	3142	char *str = elt_data->field_var_str[j++];
3124	char val_str = (char )(uintptr_t)var_val;	3143	char val_str = (char )(uintptr_t)var_val;
3125	unsigned int size;	3144	unsigned int size;
3126		3145
3127	size = min(val->size, STR_VAR_LEN_MAX);	3146	if (val->flags & HIST_FIELD_FL_STRING) {
3128	strscpy(str, val_str, size);	3147	size = min(val->size, STR_VAR_LEN_MAX);
		3148	strscpy(str, val_str, size);
		3149	} else {
		3150	char *stack_start = str + sizeof(unsigned long);
		3151	int e;
		3152
		3153	e = stack_trace_save((void *)stack_start,
		3154	HIST_STACKTRACE_DEPTH,
		3155	HIST_STACKTRACE_SKIP);
		3156	if (e < HIST_STACKTRACE_DEPTH - 1)
		3157	((unsigned long *)stack_start)[e] = 0;
		3158	((unsigned long )str) = e;
		3159	}
3129	var_val = (u64)(uintptr_t)str;	3160	var_val = (u64)(uintptr_t)str;
3130	}	3161	}
3131	tracing_map_set_var(elt, var_idx, var_val);	3162	tracing_map_set_var(elt, var_idx, var_val);
@@ -3824,7 +3855,8 @@ static void save_field_var(struct hist_trigger_data *hist_data, · 692 unmodified lines
3824	{	3855	{
3825	hist_data->field_vars[hist_data->n_field_vars++] = field_var;	3856	hist_data->field_vars[hist_data->n_field_vars++] = field_var;
3826		3857
3827	if (field_var->val->flags & HIST_FIELD_FL_STRING)	3858	/* Stack traces are saved in the string storage too */
		3859	if (field_var->val->flags & (HIST_FIELD_FL_STRING \| HIST_FIELD_FL_STACKTRACE))
3828	hist_data->n_field_var_str++;	3860	hist_data->n_field_var_str++;
3829	}	3861	}
3830		3862
@@ -3849,6 +3881,9 @@ static int check_synth_field(struct synth_event *event, · 18 unmodified lines
3849	&& field->is_dynamic)	3881	&& field->is_dynamic)
3850	return 0;	3882	return 0;
3851		3883
		3884	if (strstr(hist_field->type, "long[") && field->is_stack)
		3885	return 0;
		3886
3852	if (strcmp(field->type, hist_field->type) != 0) {	3887	if (strcmp(field->type, hist_field->type) != 0) {
3853	if (field->size != hist_field->size \|\|	3888	if (field->size != hist_field->size \|\|
3854	(!field->is_string && field->is_signed != hist_field->is_signed))	3889	(!field->is_string && field->is_signed != hist_field->is_signed))
@@ -4103,7 +4138,8 @@ static int action_create(struct hist_trigger_data *hist_data, · 248 unmodified lines
4103	}	4138	}
4104		4139
4105	hist_data->save_vars[hist_data->n_save_vars++] = field_var;	4140	hist_data->save_vars[hist_data->n_save_vars++] = field_var;
4106	if (field_var->val->flags & HIST_FIELD_FL_STRING)	4141	if (field_var->val->flags &
		4142	(HIST_FIELD_FL_STRING \| HIST_FIELD_FL_STACKTRACE))
4107	hist_data->n_save_var_str++;	4143	hist_data->n_save_var_str++;
4108	kfree(param);	4144	kfree(param);
4109	}	4145	}
@@ -4242,6 +4278,19 @@ static u64 hist_field_execname(struct hist_field *hist_field, · 132 unmodified lines
4242	return (u64)(unsigned long)(elt_data->comm);	4278	return (u64)(unsigned long)(elt_data->comm);
4243	}	4279	}
4244		4280
		4281	static u64 hist_field_stack(struct hist_field *hist_field,
		4282	struct tracing_map_elt *elt,
		4283	struct trace_buffer *buffer,
		4284	struct ring_buffer_event *rbe,
		4285	void *event)
		4286	{
		4287	u32 str_item = (u32 )(event + hist_field->field->offset);
		4288	int str_loc = str_item & 0xffff;
		4289	char addr = (char )(event + str_loc);
		4290
		4291	return (u64)(unsigned long)addr;
		4292	}
		4293
4245	static u64 hist_fn_call(struct hist_field *hist_field,	4294	static u64 hist_fn_call(struct hist_field *hist_field,
4246	struct tracing_map_elt *elt,	4295	struct tracing_map_elt *elt,
4247	struct trace_buffer *buffer,	4296	struct trace_buffer *buffer,
@@ -4305,6 +4354,8 @@ static u64 hist_fn_call(struct hist_field *hist_field, · 57 unmodified lines
4305	return div_by_mult_and_shift(hist_field, elt, buffer, rbe, event);	4354	return div_by_mult_and_shift(hist_field, elt, buffer, rbe, event);
4306	case HIST_FIELD_FN_EXECNAME:	4355	case HIST_FIELD_FN_EXECNAME:
4307	return hist_field_execname(hist_field, elt, buffer, rbe, event);	4356	return hist_field_execname(hist_field, elt, buffer, rbe, event);
		4357	case HIST_FIELD_FN_STACK:
		4358	return hist_field_stack(hist_field, elt, buffer, rbe, event);
4308	default:	4359	default:
4309	return 0;	4360	return 0;
4310	}	4361	}
@@ -4351,7 +4402,8 @@ static int create_var_field(struct hist_trigger_data *hist_data, · 40 unmodified lines
4351	if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_EXECNAME)	4402	if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_EXECNAME)
4352	update_var_execname(hist_data->fields[val_idx]);	4403	update_var_execname(hist_data->fields[val_idx]);
4353		4404
4354	if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_STRING)	4405	if (!ret && hist_data->fields[val_idx]->flags &
		4406	(HIST_FIELD_FL_STRING \| HIST_FIELD_FL_STACKTRACE))
4355	hist_data->fields[val_idx]->var_str_idx = hist_data->n_var_str++;	4407	hist_data->fields[val_idx]->var_str_idx = hist_data->n_var_str++;
4356		4408
4357	return ret;	4409	return ret;
@@ -5092,7 +5144,8 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data, · 734 unmodified lines
5092	if (hist_field->flags & HIST_FIELD_FL_VAR) {	5144	if (hist_field->flags & HIST_FIELD_FL_VAR) {
5093	var_idx = hist_field->var.idx;	5145	var_idx = hist_field->var.idx;
5094		5146
5095	if (hist_field->flags & HIST_FIELD_FL_STRING) {	5147	if (hist_field->flags &
		5148	(HIST_FIELD_FL_STRING \| HIST_FIELD_FL_STACKTRACE)) {
5096	unsigned int str_start, var_str_idx, idx;	5149	unsigned int str_start, var_str_idx, idx;
5097	char str, val_str;	5150	char str, val_str;
5098	unsigned int size;	5151	unsigned int size;
@@ -5105,9 +5158,20 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data, · 6 unmodified lines
5105	str = elt_data->field_var_str[idx];	5158	str = elt_data->field_var_str[idx];
5106	val_str = (char *)(uintptr_t)hist_val;	5159	val_str = (char *)(uintptr_t)hist_val;
5107		5160
5108	size = min(hist_field->size, STR_VAR_LEN_MAX);	5161	if (hist_field->flags & HIST_FIELD_FL_STRING) {
5109	strscpy(str, val_str, size);	5162	size = min(hist_field->size, STR_VAR_LEN_MAX);
5110		5163	strscpy(str, val_str, size);
		5164	} else {
		5165	char *stack_start = str + sizeof(unsigned long);
		5166	int e;
		5167
		5168	e = stack_trace_save((void *)stack_start,
		5169	HIST_STACKTRACE_DEPTH,
		5170	HIST_STACKTRACE_SKIP);
		5171	if (e < HIST_STACKTRACE_DEPTH - 1)
		5172	((unsigned long *)stack_start)[e] = 0;
		5173	((unsigned long )str) = e;
		5174	}
5111	hist_val = (u64)(uintptr_t)str;	5175	hist_val = (u64)(uintptr_t)str;
5112	}	5176	}
5113	tracing_map_set_var(elt, var_idx, hist_val);	5177	tracing_map_set_var(elt, var_idx, hist_val);
@@ -5193,8 +5257,17 @@ static void event_hist_trigger(struct event_trigger_data *data, · 79 unmodified lines
5193		5257
5194	if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {	5258	if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
5195	memset(entries, 0, HIST_STACKTRACE_SIZE);	5259	memset(entries, 0, HIST_STACKTRACE_SIZE);
5196	stack_trace_save(entries, HIST_STACKTRACE_DEPTH,	5260	if (key_field->field) {
5197	HIST_STACKTRACE_SKIP);	5261	unsigned long *stack, n_entries;
		5262
		5263	field_contents = hist_fn_call(key_field, elt, buffer, rbe, rec);
		5264	stack = (unsigned long *)(long)field_contents;
		5265	n_entries = *stack;
		5266	memcpy(entries, ++stack, n_entries * sizeof(unsigned long));
		5267	} else {
		5268	stack_trace_save(entries, HIST_STACKTRACE_DEPTH,
		5269	HIST_STACKTRACE_SKIP);
		5270	}
5198	key = entries;	5271	key = entries;
5199	} else {	5272	} else {
5200	field_contents = hist_fn_call(key_field, elt, buffer, rbe, rec);	5273	field_contents = hist_fn_call(key_field, elt, buffer, rbe, rec);
@@ -5297,7 +5370,10 @@ static void hist_trigger_print_key(struct seq_file *m, · 96 unmodified lines
5297	seq_printf(m, "%s: %-30s[%3llu]", field_name,	5370	seq_printf(m, "%s: %-30s[%3llu]", field_name,
5298	syscall_name, uval);	5371	syscall_name, uval);
5299	} else if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {	5372	} else if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
5300	seq_puts(m, "stacktrace:\n");	5373	if (key_field->field)
		5374	seq_printf(m, "%s.stacktrace", key_field->field->name);
		5375	else
		5376	seq_puts(m, "stacktrace:\n");
5301	hist_trigger_stacktrace_print(m,	5377	hist_trigger_stacktrace_print(m,
5302	key + key_field->offset,	5378	key + key_field->offset,
5303	HIST_STACKTRACE_DEPTH);	5379	HIST_STACKTRACE_DEPTH);
@@ -5842,7 +5918,8 @@ static void hist_field_print(struct seq_file m, struct hist_field hist_field) · 538 unmodified lines
5842		5918
5843	if (hist_field->flags) {	5919	if (hist_field->flags) {
5844	if (!(hist_field->flags & HIST_FIELD_FL_VAR_REF) &&	5920	if (!(hist_field->flags & HIST_FIELD_FL_VAR_REF) &&
5845	!(hist_field->flags & HIST_FIELD_FL_EXPR)) {	5921	!(hist_field->flags & HIST_FIELD_FL_EXPR) &&
		5922	!(hist_field->flags & HIST_FIELD_FL_STACKTRACE)) {
5846	const char *flags = get_hist_field_flags(hist_field);	5923	const char *flags = get_hist_field_flags(hist_field);
5847		5924
5848	if (flags)	5925	if (flags)
@@ -5875,9 +5952,12 @@ static int event_hist_trigger_print(struct seq_file *m, · 26 unmodified lines
5875	if (i > hist_data->n_vals)	5952	if (i > hist_data->n_vals)
5876	seq_puts(m, ",");	5953	seq_puts(m, ",");
5877		5954
5878	if (field->flags & HIST_FIELD_FL_STACKTRACE)	5955	if (field->flags & HIST_FIELD_FL_STACKTRACE) {
5879	seq_puts(m, "stacktrace");	5956	if (field->field)
5880	else	5957	seq_printf(m, "%s.stacktrace", field->field->name);
		5958	else
		5959	seq_puts(m, "stacktrace");
		5960	} else
5881	hist_field_print(m, field);	5961	hist_field_print(m, field);
5882	}	5962	}
5883		5963

kernel/trace/trace_events_synth.c+86−4

@@ -173,6 +173,14 @@ static int synth_field_is_string(char *type) · 172 unmodified lines
173	return false;	173	return false;
174	}	174	}
175		175
		176	static int synth_field_is_stack(char *type)
		177	{
		178	if (strstr(type, "long[") != NULL)
		179	return true;
		180
		181	return false;
		182	}
		183
176	static int synth_field_string_size(char *type)	184	static int synth_field_string_size(char *type)
177	{	185	{
178	char buf[4], end, start;	186	char buf[4], end, start;
@@ -248,6 +256,8 @@ static int synth_field_size(char *type) · 69 unmodified lines
248	size = sizeof(gfp_t);	256	size = sizeof(gfp_t);
249	else if (synth_field_is_string(type))	257	else if (synth_field_is_string(type))
250	size = synth_field_string_size(type);	258	size = synth_field_string_size(type);
		259	else if (synth_field_is_stack(type))
		260	size = 0;
251		261
252	return size;	262	return size;
253	}	263	}
@@ -292,6 +302,8 @@ static const char synth_field_fmt(char type) · 38 unmodified lines
292	fmt = "%x";	302	fmt = "%x";
293	else if (synth_field_is_string(type))	303	else if (synth_field_is_string(type))
294	fmt = "%.*s";	304	fmt = "%.*s";
		305	else if (synth_field_is_stack(type))
		306	fmt = "%s";
295		307
296	return fmt;	308	return fmt;
297	}	309	}
@@ -371,6 +383,23 @@ static enum print_line_t print_synth_event(struct trace_iterator *iter, · 73 unmodified lines
371	i == se->n_fields - 1 ? "" : " ");	383	i == se->n_fields - 1 ? "" : " ");
372	n_u64 += STR_VAR_LEN_MAX / sizeof(u64);	384	n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
373	}	385	}
		386	} else if (se->fields[i]->is_stack) {
		387	u32 offset, data_offset, len;
		388	unsigned long p, end;
		389
		390	offset = (u32)entry->fields[n_u64];
		391	data_offset = offset & 0xffff;
		392	len = offset >> 16;
		393
		394	p = (void *)entry + data_offset;
		395	end = (void *)p + len - (sizeof(long) - 1);
		396
		397	trace_seq_printf(s, "%s=STACK:\n", se->fields[i]->name);
		398
		399	for (; *p && p < end; p++)
		400	trace_seq_printf(s, "=> %pS\n", (void )p);
		401	n_u64++;
		402
374	} else {	403	} else {
375	struct trace_print_flags __flags[] = {	404	struct trace_print_flags __flags[] = {
376	__def_gfpflag_names, {-1, NULL} };	405	__def_gfpflag_names, {-1, NULL} };
@@ -416,8 +445,7 @@ static unsigned int trace_string(struct synth_trace_event *entry, · 39 unmodified lines
416	if (is_dynamic) {	445	if (is_dynamic) {
417	u32 data_offset;	446	u32 data_offset;
418		447
419	data_offset = offsetof(typeof(*entry), fields);	448	data_offset = struct_size(entry, fields, event->n_u64);
420	data_offset += event->n_u64 * sizeof(u64);
421	data_offset += data_size;	449	data_offset += data_size;
422		450
423	len = kern_fetch_store_strlen((unsigned long)str_val);	451	len = kern_fetch_store_strlen((unsigned long)str_val);
@@ -447,6 +475,43 @@ static unsigned int trace_string(struct synth_trace_event *entry, · 23 unmodified lines
447	return len;	475	return len;
448	}	476	}
449		477
		478	static unsigned int trace_stack(struct synth_trace_event *entry,
		479	struct synth_event *event,
		480	long *stack,
		481	unsigned int data_size,
		482	unsigned int *n_u64)
		483	{
		484	unsigned int len;
		485	u32 data_offset;
		486	void *data_loc;
		487
		488	data_offset = struct_size(entry, fields, event->n_u64);
		489	data_offset += data_size;
		490
		491	for (len = 0; len < HIST_STACKTRACE_DEPTH; len++) {
		492	if (!stack[len])
		493	break;
		494	}
		495
		496	/* Include the zero'd element if it fits */
		497	if (len < HIST_STACKTRACE_DEPTH)
		498	len++;
		499
		500	len *= sizeof(long);
		501
		502	/* Find the dynamic section to copy the stack into. */
		503	data_loc = (void *)entry + data_offset;
		504	memcpy(data_loc, stack, len);
		505
		506	/* Fill in the field that holds the offset/len combo */
		507	data_offset \|= len << 16;
		508	(u32 )&entry->fields[*n_u64] = data_offset;
		509
		510	(*n_u64)++;
		511
		512	return len;
		513	}
		514
450	static notrace void trace_event_raw_event_synth(void *__data,	515	static notrace void trace_event_raw_event_synth(void *__data,
451	u64 *var_ref_vals,	516	u64 *var_ref_vals,
452	unsigned int *var_ref_idx)	517	unsigned int *var_ref_idx)
@@ -473,7 +538,12 @@ static notrace void trace_event_raw_event_synth(void *__data, · 20 unmodified lines
473	val_idx = var_ref_idx[field_pos];	538	val_idx = var_ref_idx[field_pos];
474	str_val = (char *)(long)var_ref_vals[val_idx];	539	str_val = (char *)(long)var_ref_vals[val_idx];
475		540
476	len = kern_fetch_store_strlen((unsigned long)str_val);	541	if (event->dynamic_fields[i]->is_stack) {
		542	len = ((unsigned long )str_val);
		543	len *= sizeof(unsigned long);
		544	} else {
		545	len = kern_fetch_store_strlen((unsigned long)str_val);
		546	}
477		547
478	fields_size += len;	548	fields_size += len;
479	}	549	}
@@ -499,6 +569,12 @@ static notrace void trace_event_raw_event_synth(void *__data, · 19 unmodified lines
499	event->fields[i]->is_dynamic,	569	event->fields[i]->is_dynamic,
500	data_size, &n_u64);	570	data_size, &n_u64);
501	data_size += len; /* only dynamic string increments */	571	data_size += len; /* only dynamic string increments */
		572	} else if (event->fields[i]->is_stack) {
		573	long stack = (long )(long)var_ref_vals[val_idx];
		574
		575	len = trace_stack(entry, event, stack,
		576	data_size, &n_u64);
		577	data_size += len;
502	} else {	578	} else {
503	struct synth_field *field = event->fields[i];	579	struct synth_field *field = event->fields[i];
504	u64 val = var_ref_vals[val_idx];	580	u64 val = var_ref_vals[val_idx];
@@ -561,6 +637,9 @@ static int __set_synth_event_print_fmt(struct synth_event *event, · 56 unmodified lines
561	event->fields[i]->is_dynamic)	637	event->fields[i]->is_dynamic)
562	pos += snprintf(buf + pos, LEN_OR_ZERO,	638	pos += snprintf(buf + pos, LEN_OR_ZERO,
563	", __get_str(%s)", event->fields[i]->name);	639	", __get_str(%s)", event->fields[i]->name);
		640	else if (event->fields[i]->is_stack)
		641	pos += snprintf(buf + pos, LEN_OR_ZERO,
		642	", __get_stacktrace(%s)", event->fields[i]->name);
564	else	643	else
565	pos += snprintf(buf + pos, LEN_OR_ZERO,	644	pos += snprintf(buf + pos, LEN_OR_ZERO,
566	", REC->%s", event->fields[i]->name);	645	", REC->%s", event->fields[i]->name);
@@ -697,7 +776,8 @@ static struct synth_field parse_synth_field(int argc, char *argv, · 130 unmodified lines
697	ret = -EINVAL;	776	ret = -EINVAL;
698	goto free;	777	goto free;
699	} else if (size == 0) {	778	} else if (size == 0) {
700	if (synth_field_is_string(field->type)) {	779	if (synth_field_is_string(field->type) \|\|
		780	synth_field_is_stack(field->type)) {
701	char *type;	781	char *type;
702		782
703	len = sizeof("__data_loc ") + strlen(field->type) + 1;	783	len = sizeof("__data_loc ") + strlen(field->type) + 1;
@@ -728,6 +808,8 @@ static struct synth_field parse_synth_field(int argc, char *argv, · 24 unmodified lines
728		808
729	if (synth_field_is_string(field->type))	809	if (synth_field_is_string(field->type))
730	field->is_string = true;	810	field->is_string = true;
		811	else if (synth_field_is_stack(field->type))
		812	field->is_stack = true;
731		813
732	field->is_signed = synth_field_signed(field->type);	814	field->is_signed = synth_field_signed(field->type);
733	out:	815	out:

kernel/trace/trace_osnoise.c+1−1

@@ -1539,7 +1539,7 @@ static void osnoise_sleep(void) · 1538 unmodified lines
1539	wake_time = ktime_add_us(ktime_get(), interval);	1539	wake_time = ktime_add_us(ktime_get(), interval);
1540	__set_current_state(TASK_INTERRUPTIBLE);	1540	__set_current_state(TASK_INTERRUPTIBLE);
1541		1541
1542	while (schedule_hrtimeout_range(&wake_time, 0, HRTIMER_MODE_ABS)) {	1542	while (schedule_hrtimeout(&wake_time, HRTIMER_MODE_ABS)) {
1543	if (kthread_should_stop())	1543	if (kthread_should_stop())
1544	break;	1544	break;
1545	}	1545	}

kernel/trace/trace_seq.c+23−0

@@ -403,3 +403,26 @@ int trace_seq_hex_dump(struct trace_seq s, const char prefix_str, · 402 unmodified lines
403	return 1;	403	return 1;
404	}	404	}
405	EXPORT_SYMBOL(trace_seq_hex_dump);	405	EXPORT_SYMBOL(trace_seq_hex_dump);
		406
		407	/*
		408	* trace_seq_acquire - acquire seq buffer with size len
		409	* @s: trace sequence descriptor
		410	* @len: size of buffer to be acquired
		411	*
		412	* acquire buffer with size of @len from trace_seq for output usage,
		413	* user can fill string into that buffer.
		414	*
		415	* Returns start address of acquired buffer.
		416	*
		417	* it allow multiple usage in one trace output function call.
		418	*/
		419	char trace_seq_acquire(struct trace_seq s, unsigned int len)
		420	{
		421	char *ret = trace_seq_buffer_ptr(s);
		422
		423	if (!WARN_ON_ONCE(seq_buf_buffer_left(&s->seq) < len))
		424	seq_buf_commit(&s->seq, len);
		425
		426	return ret;
		427	}
		428	EXPORT_SYMBOL(trace_seq_acquire);

kernel/trace/trace_synth.h+1−0

@@ -18,6 +18,7 @@ struct synth_field { · 17 unmodified lines
18	bool is_signed;	18	bool is_signed;
19	bool is_string;	19	bool is_string;
20	bool is_dynamic;	20	bool is_dynamic;
		21	bool is_stack;
21	};	22	};
22		23
23	struct synth_event {	24	struct synth_event {

kernel/tracepoint.c+2−2

@@ -571,8 +571,8 @@ static void for_each_tracepoint_range( · 570 unmodified lines
571	bool trace_module_has_bad_taint(struct module *mod)	571	bool trace_module_has_bad_taint(struct module *mod)
572	{	572	{
573	return mod->taints & ~((1 << TAINT_OOT_MODULE) \| (1 << TAINT_CRAP) \|	573	return mod->taints & ~((1 << TAINT_OOT_MODULE) \| (1 << TAINT_CRAP) \|
574	(1 << TAINT_UNSIGNED_MODULE) \|	574	(1 << TAINT_UNSIGNED_MODULE) \| (1 << TAINT_TEST) \|
575	(1 << TAINT_TEST));	575	(1 << TAINT_LIVEPATCH));
576	}	576	}
577		577
578	static BLOCKING_NOTIFIER_HEAD(tracepoint_notify_list);	578	static BLOCKING_NOTIFIER_HEAD(tracepoint_notify_list);

samples/Kconfig+7−0

@@ -46,6 +46,13 @@ config SAMPLE_FTRACE_DIRECT_MULTI · 45 unmodified lines
46	that hooks to wake_up_process and schedule, and prints	46	that hooks to wake_up_process and schedule, and prints
47	the function addresses.	47	the function addresses.
48		48
		49	config SAMPLE_FTRACE_OPS
		50	tristate "Build custom ftrace ops example"
		51	depends on FUNCTION_TRACER
		52	help
		53	This builds an ftrace ops example that hooks two functions and
		54	measures the time taken to invoke one function a number of times.
		55
49	config SAMPLE_TRACE_ARRAY	56	config SAMPLE_TRACE_ARRAY
50	tristate "Build sample module for kernel access to Ftrace instancess"	57	tristate "Build sample module for kernel access to Ftrace instancess"
51	depends on EVENT_TRACING && m	58	depends on EVENT_TRACING && m

samples/Makefile+1−0

@@ -24,6 +24,7 @@ obj-$(CONFIG_SAMPLE_TRACE_CUSTOM_EVENTS) += trace_events/ · 23 unmodified lines
24	obj-$(CONFIG_SAMPLE_TRACE_PRINTK) += trace_printk/	24	obj-$(CONFIG_SAMPLE_TRACE_PRINTK) += trace_printk/
25	obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace/	25	obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace/
26	obj-$(CONFIG_SAMPLE_FTRACE_DIRECT_MULTI) += ftrace/	26	obj-$(CONFIG_SAMPLE_FTRACE_DIRECT_MULTI) += ftrace/
		27	obj-$(CONFIG_SAMPLE_FTRACE_OPS) += ftrace/
27	obj-$(CONFIG_SAMPLE_TRACE_ARRAY) += ftrace/	28	obj-$(CONFIG_SAMPLE_TRACE_ARRAY) += ftrace/
28	subdir-$(CONFIG_SAMPLE_UHID) += uhid	29	subdir-$(CONFIG_SAMPLE_UHID) += uhid
29	obj-$(CONFIG_VIDEO_PCI_SKELETON) += v4l/	30	obj-$(CONFIG_VIDEO_PCI_SKELETON) += v4l/

samples/ftrace/Makefile+1−0

@@ -5,6 +5,7 @@ obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace-direct-too.o · 4 unmodified lines
5	obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace-direct-modify.o	5	obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace-direct-modify.o
6	obj-$(CONFIG_SAMPLE_FTRACE_DIRECT_MULTI) += ftrace-direct-multi.o	6	obj-$(CONFIG_SAMPLE_FTRACE_DIRECT_MULTI) += ftrace-direct-multi.o
7	obj-$(CONFIG_SAMPLE_FTRACE_DIRECT_MULTI) += ftrace-direct-multi-modify.o	7	obj-$(CONFIG_SAMPLE_FTRACE_DIRECT_MULTI) += ftrace-direct-multi-modify.o
		8	obj-$(CONFIG_SAMPLE_FTRACE_OPS) += ftrace-ops.o
8		9
9	CFLAGS_sample-trace-array.o := -I$(src)	10	CFLAGS_sample-trace-array.o := -I$(src)
10	obj-$(CONFIG_SAMPLE_TRACE_ARRAY) += sample-trace-array.o	11	obj-$(CONFIG_SAMPLE_TRACE_ARRAY) += sample-trace-array.o

samples/ftrace/ftrace-direct-modify.c+1−1

 #include <linux/kthread.h>
 #include <linux/ftrace.h>
 #include <asm/asm-offsets.h>
-#include <asm/nospec-branch.h>
 extern void my_direct_func1(void);
 extern void my_direct_func2(void);
 #ifdef CONFIG_X86_64
 #include <asm/ibt.h>
+#include <asm/nospec-branch.h>
 asm (
 "	.pushsection    .text, \"ax\", @progbits\n"

samples/ftrace/ftrace-direct-multi-modify.c+1−1

 #include <linux/kthread.h>
 #include <linux/ftrace.h>
 #include <asm/asm-offsets.h>
-#include <asm/nospec-branch.h>
 extern void my_direct_func1(unsigned long ip);
 extern void my_direct_func2(unsigned long ip);
 #ifdef CONFIG_X86_64
 #include <asm/ibt.h>
+#include <asm/nospec-branch.h>
 asm (
 "	.pushsection    .text, \"ax\", @progbits\n"

samples/ftrace/ftrace-direct-multi.c+1−1

 #include <linux/ftrace.h>
 #include <linux/sched/stat.h>
 #include <asm/asm-offsets.h>
-#include <asm/nospec-branch.h>
 extern void my_direct_func(unsigned long ip);
 #ifdef CONFIG_X86_64
 #include <asm/ibt.h>
+#include <asm/nospec-branch.h>
 asm (
 "	.pushsection    .text, \"ax\", @progbits\n"

samples/ftrace/ftrace-direct-too.c+1−1

 #include <linux/mm.h> /* for handle_mm_fault() */
 #include <linux/ftrace.h>
 #include <asm/asm-offsets.h>
-#include <asm/nospec-branch.h>
 extern void my_direct_func(struct vm_area_struct *vma,
 			   unsigned long address, unsigned int flags);
 #ifdef CONFIG_X86_64
 #include <asm/ibt.h>
+#include <asm/nospec-branch.h>
 asm (
 "	.pushsection    .text, \"ax\", @progbits\n"

samples/ftrace/ftrace-direct.c+1−1

 #include <linux/sched.h> /* for wake_up_process() */
 #include <linux/ftrace.h>
 #include <asm/asm-offsets.h>
-#include <asm/nospec-branch.h>
 extern void my_direct_func(struct task_struct *p);
 #ifdef CONFIG_X86_64
 #include <asm/ibt.h>
+#include <asm/nospec-branch.h>
 asm (
 "	.pushsection    .text, \"ax\", @progbits\n"

samples/ftrace/ftrace-ops.c+252−0

@@ -0,0 +1,252 @@
	1	// SPDX-License-Identifier: GPL-2.0-only
	2
	3	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	4
	5	#include <linux/ftrace.h>
	6	#include <linux/ktime.h>
	7	#include <linux/module.h>
	8
	9	#include <asm/barrier.h>
	10
	11	/*
	12	* Arbitrary large value chosen to be sufficiently large to minimize noise but
	13	* sufficiently small to complete quickly.
	14	*/
	15	static unsigned int nr_function_calls = 100000;
	16	module_param(nr_function_calls, uint, 0);
	17	MODULE_PARM_DESC(nr_function_calls, "How many times to call the relevant tracee");
	18
	19	/*
	20	* The number of ops associated with a call site affects whether a tracer can
	21	* be called directly or whether it's necessary to go via the list func, which
	22	* can be significantly more expensive.
	23	*/
	24	static unsigned int nr_ops_relevant = 1;
	25	module_param(nr_ops_relevant, uint, 0);
	26	MODULE_PARM_DESC(nr_ops_relevant, "How many ftrace_ops to associate with the relevant tracee");
	27
	28	/*
	29	* On architectures where all call sites share the same trampoline, having
	30	* tracers enabled for distinct functions can force the use of the list func
	31	* and incur overhead for all call sites.
	32	*/
	33	static unsigned int nr_ops_irrelevant;
	34	module_param(nr_ops_irrelevant, uint, 0);
	35	MODULE_PARM_DESC(nr_ops_irrelevant, "How many ftrace_ops to associate with the irrelevant tracee");
	36
	37	/*
	38	* On architectures with DYNAMIC_FTRACE_WITH_REGS, saving the full pt_regs can
	39	* be more expensive than only saving the minimal necessary regs.
	40	*/
	41	static bool save_regs;
	42	module_param(save_regs, bool, 0);
	43	MODULE_PARM_DESC(save_regs, "Register ops with FTRACE_OPS_FL_SAVE_REGS (save all registers in the trampoline)");
	44
	45	static bool assist_recursion;
	46	module_param(assist_recursion, bool, 0);
	47	MODULE_PARM_DESC(assist_reursion, "Register ops with FTRACE_OPS_FL_RECURSION");
	48
	49	static bool assist_rcu;
	50	module_param(assist_rcu, bool, 0);
	51	MODULE_PARM_DESC(assist_reursion, "Register ops with FTRACE_OPS_FL_RCU");
	52
	53	/*
	54	* By default, a trivial tracer is used which immediately returns to mimimize
	55	* overhead. Sometimes a consistency check using a more expensive tracer is
	56	* desireable.
	57	*/
	58	static bool check_count;
	59	module_param(check_count, bool, 0);
	60	MODULE_PARM_DESC(check_count, "Check that tracers are called the expected number of times\n");
	61
	62	/*
	63	* Usually it's not interesting to leave the ops registered after the test
	64	* runs, but sometimes it can be useful to leave them registered so that they
	65	* can be inspected through the tracefs 'enabled_functions' file.
	66	*/
	67	static bool persist;
	68	module_param(persist, bool, 0);
	69	MODULE_PARM_DESC(persist, "Successfully load module and leave ftrace ops registered after test completes\n");
	70
	71	/*
	72	* Marked as noinline to ensure that an out-of-line traceable copy is
	73	* generated by the compiler.
	74	*
	75	* The barrier() ensures the compiler won't elide calls by determining there
	76	* are no side-effects.
	77	*/
	78	static noinline void tracee_relevant(void)
	79	{
	80	barrier();
	81	}
	82
	83	/*
	84	* Marked as noinline to ensure that an out-of-line traceable copy is
	85	* generated by the compiler.
	86	*
	87	* The barrier() ensures the compiler won't elide calls by determining there
	88	* are no side-effects.
	89	*/
	90	static noinline void tracee_irrelevant(void)
	91	{
	92	barrier();
	93	}
	94
	95	struct sample_ops {
	96	struct ftrace_ops ops;
	97	unsigned int count;
	98	};
	99
	100	static void ops_func_nop(unsigned long ip, unsigned long parent_ip,
	101	struct ftrace_ops *op,
	102	struct ftrace_regs *fregs)
	103	{
	104	/* do nothing */
	105	}
	106
	107	static void ops_func_count(unsigned long ip, unsigned long parent_ip,
	108	struct ftrace_ops *op,
	109	struct ftrace_regs *fregs)
	110	{
	111	struct sample_ops *self;
	112
	113	self = container_of(op, struct sample_ops, ops);
	114	self->count++;
	115	}
	116
	117	static struct sample_ops *ops_relevant;
	118	static struct sample_ops *ops_irrelevant;
	119
	120	static struct sample_ops ops_alloc_init(void tracee, ftrace_func_t func,
	121	unsigned long flags, int nr)
	122	{
	123	struct sample_ops *ops;
	124
	125	ops = kcalloc(nr, sizeof(*ops), GFP_KERNEL);
	126	if (WARN_ON_ONCE(!ops))
	127	return NULL;
	128
	129	for (unsigned int i = 0; i < nr; i++) {
	130	ops[i].ops.func = func;
	131	ops[i].ops.flags = flags;
	132	WARN_ON_ONCE(ftrace_set_filter_ip(&ops[i].ops, (unsigned long)tracee, 0, 0));
	133	WARN_ON_ONCE(register_ftrace_function(&ops[i].ops));
	134	}
	135
	136	return ops;
	137	}
	138
	139	static void ops_destroy(struct sample_ops *ops, int nr)
	140	{
	141	if (!ops)
	142	return;
	143
	144	for (unsigned int i = 0; i < nr; i++) {
	145	WARN_ON_ONCE(unregister_ftrace_function(&ops[i].ops));
	146	ftrace_free_filter(&ops[i].ops);
	147	}
	148
	149	kfree(ops);
	150	}
	151
	152	static void ops_check(struct sample_ops *ops, int nr,
	153	unsigned int expected_count)
	154	{
	155	if (!ops \|\| !check_count)
	156	return;
	157
	158	for (unsigned int i = 0; i < nr; i++) {
	159	if (ops->count == expected_count)
	160	continue;
	161	pr_warn("Counter called %u times (expected %u)\n",
	162	ops->count, expected_count);
	163	}
	164	}
	165
	166	static ftrace_func_t tracer_relevant = ops_func_nop;
	167	static ftrace_func_t tracer_irrelevant = ops_func_nop;
	168
	169	static int __init ftrace_ops_sample_init(void)
	170	{
	171	unsigned long flags = 0;
	172	ktime_t start, end;
	173	u64 period;
	174
	175	if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && save_regs) {
	176	pr_info("this kernel does not support saving registers\n");
	177	save_regs = false;
	178	} else if (save_regs) {
	179	flags \|= FTRACE_OPS_FL_SAVE_REGS;
	180	}
	181
	182	if (assist_recursion)
	183	flags \|= FTRACE_OPS_FL_RECURSION;
	184
	185	if (assist_rcu)
	186	flags \|= FTRACE_OPS_FL_RCU;
	187
	188	if (check_count) {
	189	tracer_relevant = ops_func_count;
	190	tracer_irrelevant = ops_func_count;
	191	}
	192
	193	pr_info("registering:\n"
	194	" relevant ops: %u\n"
	195	" tracee: %ps\n"
	196	" tracer: %ps\n"
	197	" irrelevant ops: %u\n"
	198	" tracee: %ps\n"
	199	" tracer: %ps\n"
	200	" saving registers: %s\n"
	201	" assist recursion: %s\n"
	202	" assist RCU: %s\n",
	203	nr_ops_relevant, tracee_relevant, tracer_relevant,
	204	nr_ops_irrelevant, tracee_irrelevant, tracer_irrelevant,
	205	save_regs ? "YES" : "NO",
	206	assist_recursion ? "YES" : "NO",
	207	assist_rcu ? "YES" : "NO");
	208
	209	ops_relevant = ops_alloc_init(tracee_relevant, tracer_relevant,
	210	flags, nr_ops_relevant);
	211	ops_irrelevant = ops_alloc_init(tracee_irrelevant, tracer_irrelevant,
	212	flags, nr_ops_irrelevant);
	213
	214	start = ktime_get();
	215	for (unsigned int i = 0; i < nr_function_calls; i++)
	216	tracee_relevant();
	217	end = ktime_get();
	218
	219	ops_check(ops_relevant, nr_ops_relevant, nr_function_calls);
	220	ops_check(ops_irrelevant, nr_ops_irrelevant, 0);
	221
	222	period = ktime_to_ns(ktime_sub(end, start));
	223
	224	pr_info("Attempted %u calls to %ps in %lluns (%lluns / call)\n",
	225	nr_function_calls, tracee_relevant,
	226	period, div_u64(period, nr_function_calls));
	227
	228	if (persist)
	229	return 0;
	230
	231	ops_destroy(ops_relevant, nr_ops_relevant);
	232	ops_destroy(ops_irrelevant, nr_ops_irrelevant);
	233
	234	/*
	235	* The benchmark completed sucessfully, but there's no reason to keep
	236	* the module around. Return an error do the user doesn't have to
	237	* manually unload the module.
	238	*/
	239	return -EINVAL;
	240	}
	241	module_init(ftrace_ops_sample_init);
	242
	243	static void __exit ftrace_ops_sample_exit(void)
	244	{
	245	ops_destroy(ops_relevant, nr_ops_relevant);
	246	ops_destroy(ops_irrelevant, nr_ops_irrelevant);
	247	}
	248	module_exit(ftrace_ops_sample_exit);
	249
	250	MODULE_AUTHOR("Mark Rutland");
	251	MODULE_DESCRIPTION("Example of using custom ftrace_ops");
	252	MODULE_LICENSE("GPL");

samples/user_events/example.c+2−2

@@ -23,8 +23,8 @@ · 22 unmodified lines
23	#endif	23	#endif
24		24
25	/* Assumes debugfs is mounted */	25	/* Assumes debugfs is mounted */
26	const char *data_file = "/sys/kernel/debug/tracing/user_events_data";	26	const char *data_file = "/sys/kernel/tracing/user_events_data";
27	const char *status_file = "/sys/kernel/debug/tracing/user_events_status";	27	const char *status_file = "/sys/kernel/tracing/user_events_status";
28		28
29	static int event_status(long **status)	29	static int event_status(long **status)
30	{	30	{

scripts/tracing/draw_functrace.py+3−3

@@ -12,9 +12,9 @@ calls. Only the functions's names and the call time are provided. · 11 unmodified lines
12		12
13	Usage:	13	Usage:
14	Be sure that you have CONFIG_FUNCTION_TRACER	14	Be sure that you have CONFIG_FUNCTION_TRACER
15	# mount -t debugfs nodev /sys/kernel/debug	15	# mount -t tracefs nodev /sys/kernel/tracing
16	# echo function > /sys/kernel/debug/tracing/current_tracer	16	# echo function > /sys/kernel/tracing/current_tracer
17	$ cat /sys/kernel/debug/tracing/trace_pipe > ~/raw_trace_func	17	$ cat /sys/kernel/tracing/trace_pipe > ~/raw_trace_func
18	Wait some times but not too much, the script is a bit slow.	18	Wait some times but not too much, the script is a bit slow.
19	Break the pipe (Ctrl + Z)	19	Break the pipe (Ctrl + Z)
20	$ scripts/tracing/draw_functrace.py < ~/raw_trace_func > draw_functrace	20	$ scripts/tracing/draw_functrace.py < ~/raw_trace_func > draw_functrace

tools/lib/api/fs/tracing_path.c+2−2

@@ -14,8 +14,8 @@ · 13 unmodified lines
14	#include "tracing_path.h"	14	#include "tracing_path.h"
15		15
16	static char tracing_mnt[PATH_MAX] = "/sys/kernel/debug";	16	static char tracing_mnt[PATH_MAX] = "/sys/kernel/debug";
17	static char tracing_path[PATH_MAX] = "/sys/kernel/debug/tracing";	17	static char tracing_path[PATH_MAX] = "/sys/kernel/tracing";
18	static char tracing_events_path[PATH_MAX] = "/sys/kernel/debug/tracing/events";	18	static char tracing_events_path[PATH_MAX] = "/sys/kernel/tracing/events";
19		19
20	static void __tracing_path_set(const char tracing, const char mountpoint)	20	static void __tracing_path_set(const char tracing, const char mountpoint)
21	{	21	{

tools/testing/selftests/ftrace/test.d/filter/event-filter-function.tc+58−0

@@ -0,0 +1,58 @@
	1	#!/bin/sh
	2	# SPDX-License-Identifier: GPL-2.0
	3	# description: event filter function - test event filtering on functions
	4	# requires: set_event events/kmem/kmem_cache_free/filter
	5	# flags: instance
	6
	7	fail() { #msg
	8	echo $1
	9	exit_fail
	10	}
	11
	12	echo "Test event filter function name"
	13	echo 0 > tracing_on
	14	echo 0 > events/enable
	15	echo > trace
	16	echo 'call_site.function == exit_mmap' > events/kmem/kmem_cache_free/filter
	17	echo 1 > events/kmem/kmem_cache_free/enable
	18	echo 1 > tracing_on
	19	ls > /dev/null
	20	echo 0 > events/kmem/kmem_cache_free/enable
	21
	22	hitcnt=`grep kmem_cache_free trace\| grep exit_mmap \| wc -l`
	23	misscnt=`grep kmem_cache_free trace\| grep -v exit_mmap \| wc -l`
	24
	25	if [ $hitcnt -eq 0 ]; then
	26	exit_fail
	27	fi
	28
	29	if [ $misscnt -gt 0 ]; then
	30	exit_fail
	31	fi
	32
	33	address=`grep ' exit_mmap$' /proc/kallsyms \| cut -d' ' -f1`
	34
	35	echo "Test event filter function address"
	36	echo 0 > tracing_on
	37	echo 0 > events/enable
	38	echo > trace
	39	echo "call_site.function == 0x$address" > events/kmem/kmem_cache_free/filter
	40	echo 1 > events/kmem/kmem_cache_free/enable
	41	echo 1 > tracing_on
	42	sleep 1
	43	echo 0 > events/kmem/kmem_cache_free/enable
	44
	45	hitcnt=`grep kmem_cache_free trace\| grep exit_mmap \| wc -l`
	46	misscnt=`grep kmem_cache_free trace\| grep -v exit_mmap \| wc -l`
	47
	48	if [ $hitcnt -eq 0 ]; then
	49	exit_fail
	50	fi
	51
	52	if [ $misscnt -gt 0 ]; then
	53	exit_fail
	54	fi
	55
	56	reset_events_filter
	57
	58	exit 0

tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-stack.tc+24−0

@@ -0,0 +1,24 @@
	1	#!/bin/sh
	2	# SPDX-License-Identifier: GPL-2.0
	3	# description: event trigger - test inter-event histogram trigger trace action with dynamic string param
	4	# requires: set_event synthetic_events events/sched/sched_process_exec/hist "long[]' >> synthetic_events":README
	5
	6	fail() { #msg
	7	echo $1
	8	exit_fail
	9	}
	10
	11	echo "Test create synthetic event with stack"
	12
	13
	14	echo 's:wake_lat pid_t pid; u64 delta; unsigned long[] stack;' > dynamic_events
	15	echo 'hist:keys=next_pid:ts=common_timestamp.usecs,st=stacktrace if prev_state == 1\|\|prev_state == 2' >> events/sched/sched_switch/trigger
	16	echo 'hist:keys=prev_pid:delta=common_timestamp.usecs-$ts,s=$st:onmax($delta).trace(wake_lat,prev_pid,$delta,$s)' >> events/sched/sched_switch/trigger
	17	echo 1 > events/synthetic/wake_lat/enable
	18	sleep 1
	19
	20	if ! grep -q "=>.*sched" trace; then
	21	fail "Failed to create synthetic event with stack"
	22	fi
	23
	24	exit 0

tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-syntax.tc+6−0

 echo "myevent char var[10]" > synthetic_events
 grep "myevent[[:space:]]char\[10\] var" synthetic_events
+if grep -q 'long\[\]' README; then
+  # test stacktrace type
+  echo "myevent unsigned long[] var" > synthetic_events
+  grep "myevent[[:space:]]unsigned long\[\] var" synthetic_events
+fi
 do_reset
 exit 0

tools/tracing/latency/latency-collector.c+1−1

@@ -1584,7 +1584,7 @@ static void do_printloop(void arg) · 1583 unmodified lines
1584	/*	1584	/*
1585	* Toss a coin to decide if we want to sleep before printing	1585	* Toss a coin to decide if we want to sleep before printing
1586	* out the backtrace. The reason for this is that opening	1586	* out the backtrace. The reason for this is that opening
1587	* /sys/kernel/debug/tracing/trace will cause a blackout of	1587	* /sys/kernel/tracing/trace will cause a blackout of
1588	* hundreds of ms, where no latencies will be noted by the	1588	* hundreds of ms, where no latencies will be noted by the
1589	* latency tracer. Thus by randomly sleeping we try to avoid	1589	* latency tracer. Thus by randomly sleeping we try to avoid
1590	* missing traces systematically due to this. With this option	1590	* missing traces systematically due to this. With this option