From: John Siddle <jsiddle@xxxxxxxxxx> Subject: 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@xxxxxxxxxxxxxxxxxxxx: fix off-by-one] Link: http://lkml.kernel.org/r/1473450214-4049-1-git-send-email-jsiddle@xxxxxxxxxx Signed-off-by: John Siddle <jsiddle@xxxxxxxxxx> Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/hung_task.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) diff -puN kernel/hung_task.c~hung_task-allow-hung_task_panic-when-hung_task_warnings-is-0 kernel/hung_task.c --- a/kernel/hung_task.c~hung_task-allow-hung_task_panic-when-hung_task_warnings-is-0 +++ a/kernel/hung_task.c @@ -98,26 +98,26 @@ static void check_hung_task(struct task_ trace_sched_process_hang(t); - if (!sysctl_hung_task_warnings) + if (!sysctl_hung_task_warnings && !sysctl_hung_task_panic) return; - if (sysctl_hung_task_warnings > 0) - sysctl_hung_task_warnings--; - /* * Ok, the task did not get scheduled for more than 2 minutes, * complain: */ - pr_err("INFO: task %s:%d blocked for more than %ld seconds.\n", - t->comm, t->pid, timeout); - pr_err(" %s %s %.*s\n", - print_tainted(), init_utsname()->release, - (int)strcspn(init_utsname()->version, " "), - init_utsname()->version); - pr_err("\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\"" - " disables this message.\n"); - sched_show_task(t); - debug_show_all_locks(); + if (sysctl_hung_task_warnings) { + sysctl_hung_task_warnings--; + pr_err("INFO: task %s:%d blocked for more than %ld seconds.\n", + t->comm, t->pid, timeout); + pr_err(" %s %s %.*s\n", + print_tainted(), init_utsname()->release, + (int)strcspn(init_utsname()->version, " "), + init_utsname()->version); + pr_err("\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\"" + " disables this message.\n"); + sched_show_task(t); + debug_show_all_locks(); + } touch_nmi_watchdog(); _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
