Re: [PATCH] panic: add TAINT_SOFTLOCKUP

[Andrew Morton <akpm@linux-foundation.org>]

On Tue,  3 Jun 2014 22:12:35 -0400 Josh Hunt <johunt@akamai.com> wrote:

> This taint flag will be set if the system has ever entered a softlockup
> state. Similar to TAINT_WARN it is useful to know whether or not the system
> has been in a softlockup state when debugging.
> 
> ...
>
> @@ -329,6 +329,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
>  
>  		if (softlockup_panic)
>  			panic("softlockup: hung tasks");
> +		add_taint(TAINT_SOFTLOCKUP, LOCKDEP_STILL_OK);
>  		__this_cpu_write(soft_watchdog_warn, true);
>  	} else
>  		__this_cpu_write(soft_watchdog_warn, false);

Would make more sense to have applied the taint *before* calling
panic()?

diff -puN kernel/watchdog.c~panic-add-taint_softlockup-fix kernel/watchdog.c
--- a/kernel/watchdog.c~panic-add-taint_softlockup-fix
+++ a/kernel/watchdog.c
@@ -368,9 +368,9 @@ static enum hrtimer_restart watchdog_tim
 			smp_mb__after_atomic();
 		}
 
+		add_taint(TAINT_SOFTLOCKUP, LOCKDEP_STILL_OK);
 		if (softlockup_panic)
 			panic("softlockup: hung tasks");
-		add_taint(TAINT_SOFTLOCKUP, LOCKDEP_STILL_OK);
 		__this_cpu_write(soft_watchdog_warn, true);
 	} else
 		__this_cpu_write(soft_watchdog_warn, false);