From: Steven Price <steven.price@arm.com> To: Neil Roberts <nroberts@igalia.com>, Rob Herring <robh+dt@kernel.org>, Tomeu Vizoso <tomeu@tomeuvizoso.net>, Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>, Robin Murphy <robin.murphy@arm.com> Cc: dri-devel@lists.freedesktop.org, stable@vger.kernel.org Subject: Re: [PATCH 1/2] drm/shmem-helper: Check for purged buffers in fault handler Date: Wed, 24 Feb 2021 16:39:32 +0000 [thread overview] Message-ID: <3b720672-d21d-dde5-4d7d-c2c8cd00c4b5@arm.com> (raw) In-Reply-To: <20210223155125.199577-2-nroberts@igalia.com> On 23/02/2021 15:51, Neil Roberts wrote: > When a buffer is madvised as not needed and then purged, any attempts to > access the buffer from user-space should cause a bus fault. This patch > adds a check for that. > > Cc: stable@vger.kernel.org > Fixes: 17acb9f35ed7 ("drm/shmem: Add madvise state and purge helpers") > Signed-off-by: Neil Roberts <nroberts@igalia.com> Reviewed-by: Steven Price <steven.price@arm.com> > --- > drivers/gpu/drm/drm_gem_shmem_helper.c | 18 ++++++++++++++---- > 1 file changed, 14 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c > index 9825c378dfa6..b26139b1dc35 100644 > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > @@ -525,14 +525,24 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) > struct drm_gem_object *obj = vma->vm_private_data; > struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); > loff_t num_pages = obj->size >> PAGE_SHIFT; > + vm_fault_t ret; > struct page *page; > > - if (vmf->pgoff >= num_pages || WARN_ON_ONCE(!shmem->pages)) > - return VM_FAULT_SIGBUS; > + mutex_lock(&shmem->pages_lock); > + > + if (vmf->pgoff >= num_pages || > + WARN_ON_ONCE(!shmem->pages) || > + shmem->madv < 0) { > + ret = VM_FAULT_SIGBUS; > + } else { > + page = shmem->pages[vmf->pgoff]; > > - page = shmem->pages[vmf->pgoff]; > + ret = vmf_insert_page(vma, vmf->address, page); > + } > > - return vmf_insert_page(vma, vmf->address, page); > + mutex_unlock(&shmem->pages_lock); > + > + return ret; > } > > static void drm_gem_shmem_vm_open(struct vm_area_struct *vma) >
WARNING: multiple messages have this Message-ID (diff)
From: Steven Price <steven.price@arm.com> To: Neil Roberts <nroberts@igalia.com>, Rob Herring <robh+dt@kernel.org>, Tomeu Vizoso <tomeu@tomeuvizoso.net>, Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>, Robin Murphy <robin.murphy@arm.com> Cc: stable@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH 1/2] drm/shmem-helper: Check for purged buffers in fault handler Date: Wed, 24 Feb 2021 16:39:32 +0000 [thread overview] Message-ID: <3b720672-d21d-dde5-4d7d-c2c8cd00c4b5@arm.com> (raw) In-Reply-To: <20210223155125.199577-2-nroberts@igalia.com> On 23/02/2021 15:51, Neil Roberts wrote: > When a buffer is madvised as not needed and then purged, any attempts to > access the buffer from user-space should cause a bus fault. This patch > adds a check for that. > > Cc: stable@vger.kernel.org > Fixes: 17acb9f35ed7 ("drm/shmem: Add madvise state and purge helpers") > Signed-off-by: Neil Roberts <nroberts@igalia.com> Reviewed-by: Steven Price <steven.price@arm.com> > --- > drivers/gpu/drm/drm_gem_shmem_helper.c | 18 ++++++++++++++---- > 1 file changed, 14 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c > index 9825c378dfa6..b26139b1dc35 100644 > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > @@ -525,14 +525,24 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) > struct drm_gem_object *obj = vma->vm_private_data; > struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); > loff_t num_pages = obj->size >> PAGE_SHIFT; > + vm_fault_t ret; > struct page *page; > > - if (vmf->pgoff >= num_pages || WARN_ON_ONCE(!shmem->pages)) > - return VM_FAULT_SIGBUS; > + mutex_lock(&shmem->pages_lock); > + > + if (vmf->pgoff >= num_pages || > + WARN_ON_ONCE(!shmem->pages) || > + shmem->madv < 0) { > + ret = VM_FAULT_SIGBUS; > + } else { > + page = shmem->pages[vmf->pgoff]; > > - page = shmem->pages[vmf->pgoff]; > + ret = vmf_insert_page(vma, vmf->address, page); > + } > > - return vmf_insert_page(vma, vmf->address, page); > + mutex_unlock(&shmem->pages_lock); > + > + return ret; > } > > static void drm_gem_shmem_vm_open(struct vm_area_struct *vma) > _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2021-02-24 16:42 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-02-23 15:51 [PATCH 0/2] Fix purging buffers in the shmem helpers Neil Roberts 2021-02-23 15:51 ` [PATCH 1/2] drm/shmem-helper: Check for purged buffers in fault handler Neil Roberts 2021-02-23 15:51 ` Neil Roberts 2021-02-24 16:39 ` Steven Price [this message] 2021-02-24 16:39 ` Steven Price 2021-02-23 15:51 ` [PATCH v2 2/2] drm/shmem-helper: Don't remove the offset in vm_area_struct pgoff Neil Roberts 2021-02-23 15:51 ` Neil Roberts 2021-02-24 16:41 ` Steven Price 2021-02-24 16:41 ` Steven Price 2021-03-05 10:22 ` [PATCH 0/2] Fix purging buffers in the shmem helpers Steven Price
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