hung_task: allow hung_task_panic when hung_task_warnings is 0

Previously hung_task_panic would not be respected if enabled after hung_task_warnings had already been decremented to 0. Permit the kernel to panic if hung_task_panic is enabled after hung_task_warnings has already been decremented to 0 and another task hangs for hung_task_timeout_secs seconds. Check if hung_task_panic is enabled so we don't return prematurely, and check if hung_task_warnings is non-zero so we don't print the warning unnecessarily. [akpm@linux-foundation.org: fix off-by-one] Link: http://lkml.kernel.org/r/1473450214-4049-1-git-send-email-jsiddle@redhat.com Signed-off-by: John Siddle <jsiddle@redhat.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

John Siddle committed 10 years ago

Commit 48a6d641 parent e154ccc1 file · +14 −14Browse files

Showing the changes to kernel (1 of 1 file). Show all

Unified · Split

kernel/hung_task.c+14−14

@@ -98,26 +98,26 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) · 97 unmodified lines
98	98
99	99	trace_sched_process_hang(t);
100	100
101		− if (!sysctl_hung_task_warnings)
	101	+ if (!sysctl_hung_task_warnings && !sysctl_hung_task_panic)
102	102	return;
103	103
104		− if (sysctl_hung_task_warnings > 0)
105		− sysctl_hung_task_warnings--;
106		−
107	104	/*
108	105	* Ok, the task did not get scheduled for more than 2 minutes,
109	106	* complain:
110	107	*/
111		− pr_err("INFO: task %s:%d blocked for more than %ld seconds.\n",
112		− t->comm, t->pid, timeout);
113		− pr_err(" %s %s %.*s\n",
114		− print_tainted(), init_utsname()->release,
115		− (int)strcspn(init_utsname()->version, " "),
116		− init_utsname()->version);
117		− pr_err("\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\""
118		− " disables this message.\n");
119		− sched_show_task(t);
120		− debug_show_all_locks();
	108	+ if (sysctl_hung_task_warnings) {
	109	+ sysctl_hung_task_warnings--;
	110	+ pr_err("INFO: task %s:%d blocked for more than %ld seconds.\n",
	111	+ t->comm, t->pid, timeout);
	112	+ pr_err(" %s %s %.*s\n",
	113	+ print_tainted(), init_utsname()->release,
	114	+ (int)strcspn(init_utsname()->version, " "),
	115	+ init_utsname()->version);
	116	+ pr_err("\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\""
	117	+ " disables this message.\n");
	118	+ sched_show_task(t);
	119	+ debug_show_all_locks();
	120	+ }
121	121
122	122	touch_nmi_watchdog();
123	123