Revert "tracing: Add "(fault)" name injection to kernel probes"

This reverts commit 2e9906f84fc7c99388bb7123ade167250d50f1c0. It was turned out that commit 2e9906f84fc7 ("tracing: Add "(fault)" name injection to kernel probes") did not work correctly and probe events still show just '(fault)' (instead of '"(fault)"'). Also, current '(fault)' is more explicit that it faulted. This also moves FAULT_STRING macro to trace.h so that synthetic event can keep using it, and uses it in trace_probe.c too. Link: https://lore.kernel.org/all/168908495772.123124.1250788051922100079.stgit@devnote2/ Link: https://lore.kernel.org/all/20230706230642.3793a593@rorschach.local.home/

Masami Hiramatsu (Google) committed 3 years ago

Commit 4ed8f331 parent e38e2c63 files · +9 −26Browse files

Showing the changes to kernel/trace (3 of 3 files). Show all

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3 files

kernel/trace/trace.h +2 −0
kernel/trace/trace_probe.c +1 −1
kernel/trace/trace_probe_kernel.h +6 −25

kernel/trace/trace.h+2−0

@@ -113,6 +113,8 @@ enum trace_type { · 112 unmodified lines
113	113	#define MEM_FAIL(condition, fmt, ...) \
114	114	DO_ONCE_LITE_IF(condition, pr_err, "ERROR: " fmt, ##__VA_ARGS__)
115	115
	116	+#define FAULT_STRING "(fault)"
	117	+
116	118	#define HIST_STACKTRACE_DEPTH 16
117	119	#define HIST_STACKTRACE_SIZE (HIST_STACKTRACE_DEPTH * sizeof(unsigned long))
118	120	#define HIST_STACKTRACE_SKIP 5

kernel/trace/trace_probe.c+1−1

@@ -65,7 +65,7 @@ int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq s, void data, void *ent) · 64 unmodified lines
65	65	int len = (u32 )data >> 16;
66	66
67	67	if (!len)
68		− trace_seq_puts(s, "(fault)");
	68	+ trace_seq_puts(s, FAULT_STRING);
69	69	else
70	70	trace_seq_printf(s, "\"%s\"",
71	71	(const char *)get_loc_data(data, ent));

kernel/trace/trace_probe_kernel.h+6−25

@@ -2,8 +2,6 @@ · 1 unmodified line
2	2	#ifndef __TRACE_PROBE_KERNEL_H_
3	3	#define __TRACE_PROBE_KERNEL_H_
4	4
5		−#define FAULT_STRING "(fault)"
6		−
7	5	/*
8	6	* This depends on trace_probe.h, but can not include it due to
9	7	* the way trace_probe_tmpl.h is used by trace_kprobe.c and trace_eprobe.c.
@@ -15,16 +13,8 @@ static nokprobe_inline int · 5 unmodified lines
15	13	fetch_store_strlen_user(unsigned long addr)
16	14	{
17	15	const void __user uaddr = (__force const void __user )addr;
18		− int ret;
19	16
20		− ret = strnlen_user_nofault(uaddr, MAX_STRING_SIZE);
21		− /*
22		− * strnlen_user_nofault returns zero on fault, insert the
23		− * FAULT_STRING when that occurs.
24		− */
25		− if (ret <= 0)
26		− return strlen(FAULT_STRING) + 1;
27		− return ret;
	17	+ return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);
28	18	}
29	19
30	20	/* Return the length of string -- including null terminal byte */
@@ -44,18 +34,7 @@ fetch_store_strlen(unsigned long addr) · 13 unmodified lines
44	34	len++;
45	35	} while (c && ret == 0 && len < MAX_STRING_SIZE);
46	36
47		− /* For faults, return enough to hold the FAULT_STRING */
48		− return (ret < 0) ? strlen(FAULT_STRING) + 1 : len;
49		−}
50		−
51		−static nokprobe_inline void set_data_loc(int ret, void dest, void __dest, void *base, int len)
52		−{
53		− if (ret >= 0) {
54		− (u32 )dest = make_data_loc(ret, __dest - base);
55		− } else {
56		− strscpy(__dest, FAULT_STRING, len);
57		− ret = strlen(__dest) + 1;
58		− }
	37	+ return (ret < 0) ? ret : len;
59	38	}
60	39
61	40	/*
@@ -76,7 +55,8 @@ fetch_store_string_user(unsigned long addr, void dest, void base) · 14 unmodified lines
76	55	__dest = get_loc_data(dest, base);
77	56
78	57	ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);
79		− set_data_loc(ret, dest, __dest, base, maxlen);
	58	+ if (ret >= 0)
	59	+ (u32 )dest = make_data_loc(ret, __dest - base);
80	60
81	61	return ret;
82	62	}
@@ -107,7 +87,8 @@ fetch_store_string(unsigned long addr, void dest, void base) · 24 unmodified lines
107	87	* probing.
108	88	*/
109	89	ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);
110		− set_data_loc(ret, dest, __dest, base, maxlen);
	90	+ if (ret >= 0)
	91	+ (u32 )dest = make_data_loc(ret, __dest - base);
111	92
112	93	return ret;
113	94	}