diff options
| author | Neil Roberts <nroberts@igalia.com> | 2021-02-23 18:51:24 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-17 19:06:19 +0300 |
| commit | 368b53e797c94776cb0df8736343b0e28ac34f07 (patch) | |
| tree | 4299aed0398c9c848a9e6227fb62b4cfa83ee08a /drivers/gpu | |
| parent | ad106ddd33661212da2759ce5484ace8da9438d1 (diff) | |
| download | linux-368b53e797c94776cb0df8736343b0e28ac34f07.tar.xz | |
drm/shmem-helper: Check for purged buffers in fault handler
commit d611b4a0907cece060699f2fd347c492451cd2aa upstream.
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>
Signed-off-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210223155125.199577-2-nroberts@igalia.com
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/drm_gem_shmem_helper.c | 18 |
1 files 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 e00616d94f26..d37dcdbd1a76 100644 --- a/drivers/gpu/drm/drm_gem_shmem_helper.c +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -534,14 +534,24 @@ 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) |