From: Hangyu Hua <hbh25y@gmail.com> To: Andrey Grodzovsky <andrey.grodzovsky@amd.com>, yuq825@gmail.com, airlied@linux.ie, daniel@ffwll.ch Cc: dri-devel@lists.freedesktop.org, lima@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] gpu: drm: remove redundant dma_fence_put() when drm_sched_job_add_dependency() fails Date: Tue, 26 Apr 2022 10:54:56 +0800 [thread overview] Message-ID: <79b198d0-eff2-d658-4b5e-9084a834fc93@gmail.com> (raw) In-Reply-To: <b7d8956e-5ac6-8200-d8b1-4ce828f04665@amd.com> On 2022/4/25 23:42, Andrey Grodzovsky wrote: > On 2022-04-25 04:36, Hangyu Hua wrote: > >> When drm_sched_job_add_dependency() fails, dma_fence_put() will be called >> internally. Calling it again after drm_sched_job_add_dependency() >> finishes >> may result in a dangling pointer. >> >> Fix this by removing redundant dma_fence_put(). >> >> Signed-off-by: Hangyu Hua <hbh25y@gmail.com> >> --- >> drivers/gpu/drm/lima/lima_gem.c | 1 - >> drivers/gpu/drm/scheduler/sched_main.c | 1 - >> 2 files changed, 2 deletions(-) >> >> diff --git a/drivers/gpu/drm/lima/lima_gem.c >> b/drivers/gpu/drm/lima/lima_gem.c >> index 55bb1ec3c4f7..99c8e7f6bb1c 100644 >> --- a/drivers/gpu/drm/lima/lima_gem.c >> +++ b/drivers/gpu/drm/lima/lima_gem.c >> @@ -291,7 +291,6 @@ static int lima_gem_add_deps(struct drm_file >> *file, struct lima_submit *submit) >> err = drm_sched_job_add_dependency(&submit->task->base, fence); >> if (err) { >> - dma_fence_put(fence); >> return err; > > > Makes sense here > > >> } >> } >> diff --git a/drivers/gpu/drm/scheduler/sched_main.c >> b/drivers/gpu/drm/scheduler/sched_main.c >> index b81fceb0b8a2..ebab9eca37a8 100644 >> --- a/drivers/gpu/drm/scheduler/sched_main.c >> +++ b/drivers/gpu/drm/scheduler/sched_main.c >> @@ -708,7 +708,6 @@ int drm_sched_job_add_implicit_dependencies(struct >> drm_sched_job *job, >> dma_fence_get(fence); >> ret = drm_sched_job_add_dependency(job, fence); >> if (ret) { >> - dma_fence_put(fence); > > > > Not sure about this one since if you look at the relevant commits - > 'drm/scheduler: fix drm_sched_job_add_implicit_dependencies' and > 'drm/scheduler: fix drm_sched_job_add_implicit_dependencies harder' > You will see that the dma_fence_put here balances the extra dma_fence_get > above > > Andrey > I don't think so. I checked the call chain and found no additional dma_fence_get(). But dma_fence_get() needs to be called before drm_sched_job_add_dependency() to keep the counter balanced. On the other hand, dma_fence_get() and dma_fence_put() are meaningless here if threre is an extra dma_fence_get() beacause counter will not decrease to 0 during drm_sched_job_add_dependency(). I check the call chain as follows: msm_ioctl_gem_submit() -> submit_fence_sync() -> drm_sched_job_add_implicit_dependencies() Thanks, Hangyu > >> return ret; >> } >> }
WARNING: multiple messages have this Message-ID (diff)
From: Hangyu Hua <hbh25y@gmail.com> To: Andrey Grodzovsky <andrey.grodzovsky@amd.com>, yuq825@gmail.com, airlied@linux.ie, daniel@ffwll.ch Cc: lima@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] gpu: drm: remove redundant dma_fence_put() when drm_sched_job_add_dependency() fails Date: Tue, 26 Apr 2022 10:54:56 +0800 [thread overview] Message-ID: <79b198d0-eff2-d658-4b5e-9084a834fc93@gmail.com> (raw) In-Reply-To: <b7d8956e-5ac6-8200-d8b1-4ce828f04665@amd.com> On 2022/4/25 23:42, Andrey Grodzovsky wrote: > On 2022-04-25 04:36, Hangyu Hua wrote: > >> When drm_sched_job_add_dependency() fails, dma_fence_put() will be called >> internally. Calling it again after drm_sched_job_add_dependency() >> finishes >> may result in a dangling pointer. >> >> Fix this by removing redundant dma_fence_put(). >> >> Signed-off-by: Hangyu Hua <hbh25y@gmail.com> >> --- >> drivers/gpu/drm/lima/lima_gem.c | 1 - >> drivers/gpu/drm/scheduler/sched_main.c | 1 - >> 2 files changed, 2 deletions(-) >> >> diff --git a/drivers/gpu/drm/lima/lima_gem.c >> b/drivers/gpu/drm/lima/lima_gem.c >> index 55bb1ec3c4f7..99c8e7f6bb1c 100644 >> --- a/drivers/gpu/drm/lima/lima_gem.c >> +++ b/drivers/gpu/drm/lima/lima_gem.c >> @@ -291,7 +291,6 @@ static int lima_gem_add_deps(struct drm_file >> *file, struct lima_submit *submit) >> err = drm_sched_job_add_dependency(&submit->task->base, fence); >> if (err) { >> - dma_fence_put(fence); >> return err; > > > Makes sense here > > >> } >> } >> diff --git a/drivers/gpu/drm/scheduler/sched_main.c >> b/drivers/gpu/drm/scheduler/sched_main.c >> index b81fceb0b8a2..ebab9eca37a8 100644 >> --- a/drivers/gpu/drm/scheduler/sched_main.c >> +++ b/drivers/gpu/drm/scheduler/sched_main.c >> @@ -708,7 +708,6 @@ int drm_sched_job_add_implicit_dependencies(struct >> drm_sched_job *job, >> dma_fence_get(fence); >> ret = drm_sched_job_add_dependency(job, fence); >> if (ret) { >> - dma_fence_put(fence); > > > > Not sure about this one since if you look at the relevant commits - > 'drm/scheduler: fix drm_sched_job_add_implicit_dependencies' and > 'drm/scheduler: fix drm_sched_job_add_implicit_dependencies harder' > You will see that the dma_fence_put here balances the extra dma_fence_get > above > > Andrey > I don't think so. I checked the call chain and found no additional dma_fence_get(). But dma_fence_get() needs to be called before drm_sched_job_add_dependency() to keep the counter balanced. On the other hand, dma_fence_get() and dma_fence_put() are meaningless here if threre is an extra dma_fence_get() beacause counter will not decrease to 0 during drm_sched_job_add_dependency(). I check the call chain as follows: msm_ioctl_gem_submit() -> submit_fence_sync() -> drm_sched_job_add_implicit_dependencies() Thanks, Hangyu > >> return ret; >> } >> }
next prev parent reply other threads:[~2022-04-26 2:55 UTC|newest] Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-04-25 8:36 [PATCH] gpu: drm: remove redundant dma_fence_put() when drm_sched_job_add_dependency() fails Hangyu Hua 2022-04-25 8:36 ` Hangyu Hua 2022-04-25 15:42 ` Andrey Grodzovsky 2022-04-25 15:42 ` Andrey Grodzovsky 2022-04-26 2:54 ` Hangyu Hua [this message] 2022-04-26 2:54 ` Hangyu Hua 2022-04-26 14:48 ` Andrey Grodzovsky 2022-04-26 14:48 ` Andrey Grodzovsky 2022-04-26 14:55 ` Andrey Grodzovsky 2022-04-26 14:55 ` Andrey Grodzovsky 2022-04-27 2:31 ` Hangyu Hua 2022-04-27 2:31 ` Hangyu Hua 2022-04-27 14:43 ` Andrey Grodzovsky 2022-04-28 8:56 ` Hangyu Hua 2022-04-28 8:56 ` Hangyu Hua 2022-04-28 15:27 ` Andrey Grodzovsky 2022-04-28 15:27 ` Andrey Grodzovsky 2022-04-29 3:03 ` Hangyu Hua 2022-04-29 3:03 ` Hangyu Hua 2022-04-29 16:34 ` Andrey Grodzovsky 2022-04-29 16:34 ` Andrey Grodzovsky
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=79b198d0-eff2-d658-4b5e-9084a834fc93@gmail.com \ --to=hbh25y@gmail.com \ --cc=airlied@linux.ie \ --cc=andrey.grodzovsky@amd.com \ --cc=daniel@ffwll.ch \ --cc=dri-devel@lists.freedesktop.org \ --cc=lima@lists.freedesktop.org \ --cc=linux-kernel@vger.kernel.org \ --cc=yuq825@gmail.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.