hung_task: print message when hung_task_warnings gets down to zero.

It's useful to report it when hung_task_warnings gets down to zero, so
that we can know if kernel log was lost or there is no hung task was
detected.

Link: https://lkml.kernel.org/r/20230201135416.GA6560@didi-ThinkCentre-M920t-N000
Signed-off-by: fuyuanli <fuyuanli@didiglobal.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index c71889f..3228133 100644 (file)
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -142,6 +142,8 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
 
                if (sysctl_hung_task_all_cpu_backtrace)
                        hung_task_show_all_bt = true;
+               if (!sysctl_hung_task_warnings)
+                       pr_info("Future hung task reports are suppressed, see sysctl kernel.hung_task_warnings\n");
        }
 
        touch_nmi_watchdog();