From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751957AbeDXTo2 (ORCPT ); Tue, 24 Apr 2018 15:44:28 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:36374 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751476AbeDXToW (ORCPT ); Tue, 24 Apr 2018 15:44:22 -0400 X-Google-Smtp-Source: AB8JxZpWxay5ajCRdXxdkWfRDznSKqEpdFOPse954Gs63GYg9v9VuMl5a1P7ZtMy+h1XhG+gnZXGPw== Date: Tue, 24 Apr 2018 21:44:18 +0200 From: Daniel Vetter To: Michel =?iso-8859-1?Q?D=E4nzer?= Cc: Andrey Grodzovsky , linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, David.Panariti@amd.com, oleg@redhat.com, ebiederm@xmission.com, Alexander.Deucher@amd.com, akpm@linux-foundation.org, Christian.Koenig@amd.com Subject: Re: [PATCH 2/3] drm/scheduler: Don't call wait_event_killable for signaled process. Message-ID: <20180424194418.GE25142@phenom.ffwll.local> Mail-Followup-To: Michel =?iso-8859-1?Q?D=E4nzer?= , Andrey Grodzovsky , linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, David.Panariti@amd.com, oleg@redhat.com, ebiederm@xmission.com, Alexander.Deucher@amd.com, akpm@linux-foundation.org, Christian.Koenig@amd.com References: <1524583836-12130-1-git-send-email-andrey.grodzovsky@amd.com> <1524583836-12130-3-git-send-email-andrey.grodzovsky@amd.com> <7313704c-0693-0bb9-8818-99cd2b7c0ca0@daenzer.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <7313704c-0693-0bb9-8818-99cd2b7c0ca0@daenzer.net> X-Operating-System: Linux phenom 4.15.0-1-amd64 User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > > --- > > 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