Andrey Grodzovsky <andrey.grodzovsky@xxxxxxx> writes:
Avoid calling wait_event_killable when you are possibly being calledI am curious what the call path that is problematic here.
from get_signal routine since in that case you end up in a deadlock
where you are alreay blocked in singla processing any trying to wait
on a new signal.
In general waiting seems wrong when the process has already been
fatally killed as indicated by PF_SIGNALED.
Returning -ERESTARTSYS seems wrong as nothing should make it back even
to the edge of userspace here.
Given that this is the only use of PF_SIGNALED outside of bsd process
accounting I find this code very suspicious.
It looks the code path that gets called during exit is buggy and needs
to be sorted out.
Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@xxxxxxx>
drivers/gpu/drm/scheduler/gpu_scheduler.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/gpu_scheduler.c b/drivers/gpu/drm/scheduler/gpu_scheduler.c
index 088ff2b..09fd258 100644
@@ -227,9 +227,10 @@ void drm_sched_entity_do_release(struct drm_gpu_scheduler *sched,
* The client will not queue more IBs during this fini, consume existing
- * queued IBs or discard them on SIGKILL
+ * queued IBs or discard them when in death signal state since
+ * wait_event_killable can't receive signals in that state.
- if ((current->flags & PF_SIGNALED) && current->exit_code == SIGKILL)
+ if (current->flags & PF_SIGNALED)
entity->fini_status = -ERESTARTSYS;
entity->fini_status = wait_event_killable(sched->job_scheduled,