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signal: don't allow STOP on PF_IO_WORKER threads

Just like we don't allow normal signals to IO threads, don't deliver a
STOP to a task that has PF_IO_WORKER set. The IO threads don't take
signals in general, and have no means of flushing out a stop either.

Longer term, we may want to look into allowing stop of these threads,
as it relates to eg process freezing. For now, this prevents a spin
issue if a SIGSTOP is delivered to the parent task.

Reported-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
rM2-mainline
Eric W. Biederman 2021-03-21 09:37:48 -06:00 committed by Jens Axboe
parent 5be28c8f85
commit 4db4b1a0d1
1 changed files with 2 additions and 1 deletions

View File

@ -288,7 +288,8 @@ bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
if (unlikely(fatal_signal_pending(task) ||
(task->flags & (PF_EXITING | PF_IO_WORKER))))
return false;
if (mask & JOBCTL_STOP_SIGMASK)