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SubjectRe: [syzbot] [bpf?] [trace?] WARNING: locking bug in __lock_task_sighand
On Mon, Dec 2, 2024 at 4:42 AM Puranjay Mohan <puranjay@kernel.org> wrote:
>
> Alexei Starovoitov <alexei.starovoitov@gmail.com> writes:
>
> > Puranjay, Andrii and All,
> >
> > looks like if (irqs_disabled()) is not enough.
> > Should we change it to preemptible() ?
> >
> > It will likely make it async all the time,
> > but in this it's an ok trade off?
> >
>
> Yes, as BPF programs can run in all kinds of contexts.
>
> We should replace 'if (irqs_disabled())' with 'if (!preemptible())'
>
> because the definition is:
>
> #define preemptible() (preempt_count() == 0 && !irqs_disabled())
>
> and we need if ((preempt_count() != 0) || irqs_disabled()), in both
> these cases we want to make it async.
>
> I will try to test the fix as Syzbot has now found a reproducer.

Puranjay,

Any progress on a patch ?

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