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SubjectRe: [PATCH 1/3] signals: Allow generation of SIGKILL to exiting task.
Andrey Grodzovsky <andrey.grodzovsky@amd.com> writes:

> Currently calling wait_event_killable as part of exiting process
> will stall forever since SIGKILL generation is suppresed by PF_EXITING.
>
> In our partilaur case AMDGPU driver wants to flush all GPU jobs in
> flight before shutting down. But if some job hangs the pipe we still want to
> be able to kill it and avoid a process in D state.

This makes me profoundly uncomfotable. You are changing the linux
semantics of what it means for a process to be exiting. Functionally
this may require all kinds of changes to when we allow processes to stop
processing signals.

So without a really good thought out explanation that takes into account
all of the issues involved in process exiting and posix conformance.

Nacked-by: "Eric W. Biederman" <ebiederm@xmission.com>

Eric

> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
> ---
> kernel/signal.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/signal.c b/kernel/signal.c
> index c6e4c83..c49c706 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -886,10 +886,10 @@ static inline int wants_signal(int sig, struct task_struct *p)
> {
> if (sigismember(&p->blocked, sig))
> return 0;
> - if (p->flags & PF_EXITING)
> - return 0;
> if (sig == SIGKILL)
> return 1;
> + if (p->flags & PF_EXITING)
> + return 0;
> if (task_is_stopped_or_traced(p))
> return 0;
> return task_curr(p) || !signal_pending(p);

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