Messages in this thread | | | From | Roman Penyaev <> | Date | Mon, 24 Oct 2016 21:09:33 +0200 | Subject | Re: [PATCH v2 2/2] workqueue: ignore dead tasks in a workqueue sleep hook |
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On Mon, Oct 24, 2016 at 6:40 PM, Peter Zijlstra <peterz@infradead.org> wrote: > On Mon, Oct 24, 2016 at 06:08:14PM +0200, Roman Pen wrote: > >> --- a/kernel/workqueue.c >> +++ b/kernel/workqueue.c >> @@ -875,9 +875,31 @@ void wq_worker_waking_up(struct task_struct *task, int cpu) >> */ >> struct task_struct *wq_worker_sleeping(struct task_struct *task) >> { >> - struct worker *worker = kthread_data(task), *to_wakeup = NULL; >> + struct worker *worker, *to_wakeup = NULL; >> struct worker_pool *pool; >> >> + >> + if (task->state == TASK_DEAD) >> + /* Here we try to catch the following path before >> + * accessing NULL kthread->vfork_done ptr thru >> + * kthread_data(): >> + * >> + * oops_end() >> + * do_exit() >> + * schedule() >> + * >> + * If panic_on_oops is not set and oops happens on >> + * a workqueue execution path, thread will be killed. >> + * That is definitly sad, but not to make the situation >> + * even worse we have to ignore dead tasks in order not >> + * to step on zeroed out members (e.g. t->vfork_done is >> + * already NULL on that path, since we were called by >> + * do_exit())). >> + */ >> + return NULL; > > https://lkml.kernel.org/r/CA+55aFyQYJerovMsSoSKS7PessZBr4vNp-3QUUwhqk4A4_jcbg@mail.gmail.com
Ha, explicit comment from Linus :) Ok.
> Also, that misses { }.
Ok.
-- Roman
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