From: Boris Brezillon <boris.brezillon@collabora.com> To: Steven Price <steven.price@arm.com> Cc: Rob Herring <robh+dt@kernel.org>, Tomeu Vizoso <tomeu@tomeuvizoso.net>, Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>, stable@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH 2/8] drm/panfrost: Fix a race in panfrost_ioctl_madvise() Date: Fri, 29 Nov 2019 15:33:10 +0100 [thread overview] Message-ID: <20191129153310.2f9c80e1@collabora.com> (raw) In-Reply-To: <dd8a946c-5666-a7b8-f7bc-06647e0d0bbc@arm.com> On Fri, 29 Nov 2019 14:24:48 +0000 Steven Price <steven.price@arm.com> wrote: > On 29/11/2019 13:59, Boris Brezillon wrote: > > If 2 threads change the MADVISE property of the same BO in parallel we > > might end up with an shmem->madv value that's inconsistent with the > > presence of the BO in the shrinker list. > > I'm a bit worried from the point of view of user space sanity that you > observed this - but clearly the kernel should be robust! It's not something I observed, just found the race by inspecting the code, and I thought it was worth fixing it. > > > > > The easiest solution to fix that is to protect the > > drm_gem_shmem_madvise() call with the shrinker lock. > > > > Fixes: 013b65101315 ("drm/panfrost: Add madvise and shrinker support") > > Cc: <stable@vger.kernel.org> > > Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com> > > Reviewed-by: Steven Price <steven.price@arm.com> Thanks. > > > --- > > drivers/gpu/drm/panfrost/panfrost_drv.c | 9 ++++----- > > 1 file changed, 4 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c > > index f21bc8a7ee3a..efc0a24d1f4c 100644 > > --- a/drivers/gpu/drm/panfrost/panfrost_drv.c > > +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c > > @@ -347,20 +347,19 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data, > > return -ENOENT; > > } > > > > + mutex_lock(&pfdev->shrinker_lock); > > args->retained = drm_gem_shmem_madvise(gem_obj, args->madv); > > > > if (args->retained) { > > struct panfrost_gem_object *bo = to_panfrost_bo(gem_obj); > > > > - mutex_lock(&pfdev->shrinker_lock); > > - > > if (args->madv == PANFROST_MADV_DONTNEED) > > - list_add_tail(&bo->base.madv_list, &pfdev->shrinker_list); > > + list_add_tail(&bo->base.madv_list, > > + &pfdev->shrinker_list); > > else if (args->madv == PANFROST_MADV_WILLNEED) > > list_del_init(&bo->base.madv_list); > > - > > - mutex_unlock(&pfdev->shrinker_lock); > > } > > + mutex_unlock(&pfdev->shrinker_lock); > > > > drm_gem_object_put_unlocked(gem_obj); > > return 0; > > >
WARNING: multiple messages have this Message-ID (diff)
From: Boris Brezillon <boris.brezillon@collabora.com> To: Steven Price <steven.price@arm.com> Cc: stable@vger.kernel.org, dri-devel@lists.freedesktop.org, Rob Herring <robh+dt@kernel.org>, Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com> Subject: Re: [PATCH 2/8] drm/panfrost: Fix a race in panfrost_ioctl_madvise() Date: Fri, 29 Nov 2019 15:33:10 +0100 [thread overview] Message-ID: <20191129153310.2f9c80e1@collabora.com> (raw) Message-ID: <20191129143310.lsYbRMu6KidkWA15jVJOCQU6WYHQ1twEPzfXtLW3pKw@z> (raw) In-Reply-To: <dd8a946c-5666-a7b8-f7bc-06647e0d0bbc@arm.com> On Fri, 29 Nov 2019 14:24:48 +0000 Steven Price <steven.price@arm.com> wrote: > On 29/11/2019 13:59, Boris Brezillon wrote: > > If 2 threads change the MADVISE property of the same BO in parallel we > > might end up with an shmem->madv value that's inconsistent with the > > presence of the BO in the shrinker list. > > I'm a bit worried from the point of view of user space sanity that you > observed this - but clearly the kernel should be robust! It's not something I observed, just found the race by inspecting the code, and I thought it was worth fixing it. > > > > > The easiest solution to fix that is to protect the > > drm_gem_shmem_madvise() call with the shrinker lock. > > > > Fixes: 013b65101315 ("drm/panfrost: Add madvise and shrinker support") > > Cc: <stable@vger.kernel.org> > > Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com> > > Reviewed-by: Steven Price <steven.price@arm.com> Thanks. > > > --- > > drivers/gpu/drm/panfrost/panfrost_drv.c | 9 ++++----- > > 1 file changed, 4 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c > > index f21bc8a7ee3a..efc0a24d1f4c 100644 > > --- a/drivers/gpu/drm/panfrost/panfrost_drv.c > > +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c > > @@ -347,20 +347,19 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data, > > return -ENOENT; > > } > > > > + mutex_lock(&pfdev->shrinker_lock); > > args->retained = drm_gem_shmem_madvise(gem_obj, args->madv); > > > > if (args->retained) { > > struct panfrost_gem_object *bo = to_panfrost_bo(gem_obj); > > > > - mutex_lock(&pfdev->shrinker_lock); > > - > > if (args->madv == PANFROST_MADV_DONTNEED) > > - list_add_tail(&bo->base.madv_list, &pfdev->shrinker_list); > > + list_add_tail(&bo->base.madv_list, > > + &pfdev->shrinker_list); > > else if (args->madv == PANFROST_MADV_WILLNEED) > > list_del_init(&bo->base.madv_list); > > - > > - mutex_unlock(&pfdev->shrinker_lock); > > } > > + mutex_unlock(&pfdev->shrinker_lock); > > > > drm_gem_object_put_unlocked(gem_obj); > > return 0; > > > _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2019-11-29 14:33 UTC|newest] Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-11-29 13:59 [PATCH 0/8] panfrost: Fixes for 5.4 Boris Brezillon 2019-11-29 13:59 ` [PATCH 1/8] drm/panfrost: Make panfrost_job_run() return an ERR_PTR() instead of NULL Boris Brezillon 2019-11-29 13:59 ` Boris Brezillon 2019-11-29 14:19 ` Steven Price 2019-11-29 14:19 ` Steven Price 2019-11-29 14:31 ` Boris Brezillon 2019-11-29 14:31 ` Boris Brezillon 2019-11-29 14:38 ` Steven Price 2019-11-29 14:38 ` Steven Price 2019-11-29 19:32 ` Boris Brezillon 2019-11-29 19:32 ` Boris Brezillon 2019-11-29 13:59 ` [PATCH 2/8] drm/panfrost: Fix a race in panfrost_ioctl_madvise() Boris Brezillon 2019-11-29 13:59 ` Boris Brezillon 2019-11-29 14:24 ` Steven Price 2019-11-29 14:24 ` Steven Price 2019-11-29 14:33 ` Boris Brezillon [this message] 2019-11-29 14:33 ` Boris Brezillon 2019-11-29 14:40 ` Steven Price 2019-11-29 14:40 ` Steven Price 2019-11-29 20:07 ` Daniel Vetter 2019-11-29 20:07 ` Daniel Vetter 2019-11-29 21:45 ` Boris Brezillon 2019-11-29 21:45 ` Boris Brezillon 2019-12-05 23:08 ` Rob Herring 2019-12-05 23:08 ` Rob Herring 2019-12-06 7:53 ` Boris Brezillon 2019-12-06 7:53 ` Boris Brezillon 2019-12-06 8:08 ` Boris Brezillon 2019-12-06 8:08 ` Boris Brezillon 2019-11-29 13:59 ` [PATCH 3/8] drm/panfrost: Fix a BO leak in panfrost_ioctl_mmap_bo() Boris Brezillon 2019-11-29 13:59 ` Boris Brezillon 2019-11-29 14:26 ` Steven Price 2019-11-29 14:26 ` Steven Price 2019-11-29 13:59 ` [PATCH 4/8] drm/panfrost: Fix a race in panfrost_gem_free_object() Boris Brezillon 2019-11-29 13:59 ` Boris Brezillon 2019-11-29 14:28 ` Steven Price 2019-11-29 14:28 ` Steven Price 2019-11-29 13:59 ` [PATCH 5/8] drm/panfrost: Open/close the perfcnt BO Boris Brezillon 2019-11-29 13:59 ` Boris Brezillon 2019-11-29 14:34 ` Steven Price 2019-11-29 14:34 ` Steven Price 2019-11-29 13:59 ` [PATCH 6/8] drm/panfrost: Make sure imported/exported BOs are never purged Boris Brezillon 2019-11-29 13:59 ` Boris Brezillon 2019-11-29 14:14 ` Boris Brezillon 2019-11-29 14:14 ` Boris Brezillon 2019-11-29 14:45 ` Steven Price 2019-11-29 14:45 ` Steven Price 2019-11-29 14:52 ` Boris Brezillon 2019-11-29 14:52 ` Boris Brezillon 2019-11-29 20:12 ` Daniel Vetter 2019-11-29 20:12 ` Daniel Vetter 2019-11-29 21:09 ` Boris Brezillon 2019-11-29 21:09 ` Boris Brezillon 2019-12-02 8:52 ` Daniel Vetter 2019-12-02 8:52 ` Daniel Vetter 2019-12-02 9:50 ` Boris Brezillon 2019-12-02 9:50 ` Boris Brezillon 2019-11-29 13:59 ` [PATCH 7/8] drm/panfrost: Add the panfrost_gem_mapping concept Boris Brezillon 2019-11-29 13:59 ` Boris Brezillon 2019-11-29 15:37 ` Steven Price 2019-11-29 15:37 ` Steven Price 2019-11-29 20:14 ` Daniel Vetter 2019-11-29 20:14 ` Daniel Vetter 2019-11-29 21:36 ` Boris Brezillon 2019-11-29 21:36 ` Boris Brezillon 2019-12-02 8:55 ` Daniel Vetter 2019-12-02 8:55 ` Daniel Vetter 2019-12-02 9:13 ` Boris Brezillon 2019-12-02 9:13 ` Boris Brezillon 2019-12-02 9:44 ` Daniel Vetter 2019-12-02 9:44 ` Daniel Vetter 2019-12-04 11:41 ` Steven Price 2019-12-04 11:41 ` Steven Price 2019-11-29 13:59 ` [PATCH 8/8] drm/panfrost: Make sure the shrinker does not reclaim referenced BOs Boris Brezillon 2019-11-29 13:59 ` Boris Brezillon 2019-11-29 15:48 ` Steven Price 2019-11-29 15:48 ` Steven Price 2019-11-29 16:07 ` Boris Brezillon 2019-11-29 16:07 ` Boris Brezillon 2019-11-29 16:12 ` Steven Price 2019-11-29 16:12 ` Steven Price 2019-12-02 12:50 ` Robin Murphy 2019-12-02 12:50 ` Robin Murphy 2019-12-02 13:32 ` Boris Brezillon 2019-12-02 13:32 ` Boris Brezillon 2019-11-29 14:23 ` [PATCH 0/8] panfrost: Fixes for 5.4 Alyssa Rosenzweig 2019-12-06 17:16 ` Rob Herring
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=20191129153310.2f9c80e1@collabora.com \ --to=boris.brezillon@collabora.com \ --cc=alyssa.rosenzweig@collabora.com \ --cc=dri-devel@lists.freedesktop.org \ --cc=robh+dt@kernel.org \ --cc=stable@vger.kernel.org \ --cc=steven.price@arm.com \ --cc=tomeu@tomeuvizoso.net \ /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.