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Commit 585a07b8 authored by Rob Clark's avatar Rob Clark Committed by Greg Kroah-Hartman
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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: default avatar <syzbot+c8ae65286134dd1b800d@syzkaller.appspotmail.com>
Fixes: 2194a63a ("drm: Add library for shmem backed GEM objects")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarRob Clark <robdclark@chromium.org>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarJavier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221130185748.357410-2-robdclark@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b8419d16

drivers/gpu/drm/drm_gem_shmem_helper.c

+1 −3
Original line number Diff line number Diff line
@@ -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;