* __put_task_struct() WARN_ON(!tsk->exit_state)?
@ 2022-12-03 19:24 Paul E. McKenney
2022-12-05 17:00 ` Paul E. McKenney
0 siblings, 1 reply; 2+ messages in thread
From: Paul E. McKenney @ 2022-12-03 19:24 UTC (permalink / raw)
To: linux-kernel
Cc: akpm, ebiederm, tglx, bigeasy, luto, Liam.Howlett, fenghua.yu, peterz
Hello!
One of last night's rcutorture TREE03 runs triggered the
__put_task_struct() function's first WARN_ON() complaining that
the tasks's ->exit_state was zero. This was on mainline merged
into RCU's "dev" branch. There immediately follows a splat from
refcount_warn_saturate(), so there are two interlaced stack dumps. :-/
What I do have seems to implicate rt_mutex priority boosting triggered
by RCU's prioritiy boosting.
Left to myself, my next steps are to try to reproduce this. It happened
once in 150 hours of TREE03, so who knows?
But I figured I should check to see if anyone else is hitting this.
Thanx, Paul
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: __put_task_struct() WARN_ON(!tsk->exit_state)?
2022-12-03 19:24 __put_task_struct() WARN_ON(!tsk->exit_state)? Paul E. McKenney
@ 2022-12-05 17:00 ` Paul E. McKenney
0 siblings, 0 replies; 2+ messages in thread
From: Paul E. McKenney @ 2022-12-05 17:00 UTC (permalink / raw)
To: linux-kernel
Cc: akpm, ebiederm, tglx, bigeasy, luto, Liam.Howlett, fenghua.yu,
peterz, joel
On Sat, Dec 03, 2022 at 11:24:43AM -0800, Paul E. McKenney wrote:
> Hello!
>
> One of last night's rcutorture TREE03 runs triggered the
> __put_task_struct() function's first WARN_ON() complaining that
> the tasks's ->exit_state was zero. This was on mainline merged
> into RCU's "dev" branch. There immediately follows a splat from
> refcount_warn_saturate(), so there are two interlaced stack dumps. :-/
>
> What I do have seems to implicate rt_mutex priority boosting triggered
> by RCU's prioritiy boosting.
>
> Left to myself, my next steps are to try to reproduce this. It happened
> once in 150 hours of TREE03, so who knows?
>
> But I figured I should check to see if anyone else is hitting this.
And hammering this hard all weekend failed to reproduce. 1500 hours of
TREE03 and no failures.
Yet another thing going bump in the night.
Left to myself, my next step is to try out Joel's locktorture patches.
https://lore.kernel.org/lkml/20221123012104.3317665-3-joel@joelfernandes.org/
Thanx, Paul
^ permalink raw reply [flat|nested] 2+ messages in thread
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