[PATCH v2 1/2] drm/shmem-helper: Remove errant put in error path
From: Rob Clark
Date: Wed Nov 30 2022 - 13:58:08 EST
From: Rob Clark <robdclark@xxxxxxxxxxxx>
drm_gem_shmem_mmap() doesn't own this reference, resulting in the GEM
object getting prematurely freed leading to a later use-after-free.
Link: https://syzkaller.appspot.com/bug?extid=c8ae65286134dd1b800d
Reported-by: syzbot+c8ae65286134dd1b800d@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 2194a63a818d ("drm: Add library for shmem backed GEM objects")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
---
drivers/gpu/drm/drm_gem_shmem_helper.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 35138f8a375c..3b7b71391a4c 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -622,10 +622,8 @@ int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct vm_area_struct
}
ret = drm_gem_shmem_get_pages(shmem);
- if (ret) {
- drm_gem_vm_close(vma);
+ if (ret)
return ret;
- }
vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
--
2.38.1