drm/shmem-helper: Remove errant put in error path

commit 24013314be6ee4ee456114a671e9fa3461323de8 upstream.

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@syzkaller.appspotmail.com
Fixes: 2194a63a818d ("drm: Add library for shmem backed GEM objects")
Cc: stable@vger.kernel.org
Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221130185748.357410-2-robdclark@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Rob Clark 2022-11-30 10:57:47 -08:00 committed by Greg Kroah-Hartman
parent b8419d16f4
commit 585a07b820

View File

@ -554,10 +554,8 @@ int drm_gem_shmem_mmap(struct file *filp, struct vm_area_struct *vma)
shmem = to_drm_gem_shmem_obj(vma->vm_private_data);
ret = drm_gem_shmem_get_pages(shmem);
if (ret) {
drm_gem_vm_close(vma);
if (ret)
return ret;
}
/* VM_PFNMAP was set by drm_gem_mmap() */
vma->vm_flags &= ~VM_PFNMAP;