lkml.org 
[lkml]   [2018]   [Apr]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/3] drm/scheduler: Don't call wait_event_killable for signaled process.
On Tue, Apr 24, 2018 at 05:46:52PM +0200, Michel Dänzer wrote:
>
> Adding the dri-devel list, since this is driver independent code.
>
>
> On 2018-04-24 05:30 PM, Andrey Grodzovsky wrote:
> > Avoid calling wait_event_killable when you are possibly being called
> > 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
>
> Multiple typos here, "[...] already blocked in signal processing and [...]"?
>
>
> > on a new signal.
> >
> > Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
> > ---
> > 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
> > --- a/drivers/gpu/drm/scheduler/gpu_scheduler.c
> > +++ b/drivers/gpu/drm/scheduler/gpu_scheduler.c
> > @@ -227,9 +227,10 @@ void drm_sched_entity_do_release(struct drm_gpu_scheduler *sched,
> > return;
> > /**
> > * 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)

You want fatal_signal_pending() here, instead of inventing your own broken
version.
> > entity->fini_status = -ERESTARTSYS;
> > else
> > entity->fini_status = wait_event_killable(sched->job_scheduled,

But really this smells like a bug in wait_event_killable, since
wait_event_interruptible does not suffer from the same bug. It will return
immediately when there's a signal pending.

I think this should be fixed in core code, not papered over in some
subsystem.
-Daniel

> >
>
>
> --
> Earthling Michel Dänzer | http://www.amd.com
> Libre software enthusiast | Mesa and X developer
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

\
 
 \ /
  Last update: 2018-04-24 21:44    [W:0.084 / U:0.176 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site