On 2/26/19 1:44 PM, Eric Biggers wrote:
From: Eric Biggers <ebigg...@google.com>

If drm_gem_handle_create() fails in vgem_gem_create(), then the
drm_vgem_gem_object is freed twice: once when the reference is dropped
by drm_gem_object_put_unlocked(), and again by __vgem_gem_destroy().

This was hit by syzkaller using fault injection.

Fix it by skipping the second free.

Reported-by: syzbot+e73f2fb5ed5a5df36...@syzkaller.appspotmail.com
Fixes: af33a9190d02 ("drm/vgem: Enable dmabuf import interfaces")
Reviewed-by: Chris Wilson <ch...@chris-wilson.co.uk>
Cc: Laura Abbott <labb...@redhat.com>
Cc: Daniel Vetter <daniel.vet...@ffwll.ch>
Cc: sta...@vger.kernel.org
Signed-off-by: Eric Biggers <ebigg...@google.com>
---
  drivers/gpu/drm/vgem/vgem_drv.c | 6 +-----
  1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
index 5930facd6d2d8..11a8f99ba18c5 100644
--- a/drivers/gpu/drm/vgem/vgem_drv.c
+++ b/drivers/gpu/drm/vgem/vgem_drv.c
@@ -191,13 +191,9 @@ static struct drm_gem_object *vgem_gem_create(struct 
drm_device *dev,
        ret = drm_gem_handle_create(file, &obj->base, handle);
        drm_gem_object_put_unlocked(&obj->base);
        if (ret)
-               goto err;
+               return ERR_PTR(ret);
return &obj->base;
-
-err:
-       __vgem_gem_destroy(obj);
-       return ERR_PTR(ret);
  }
static int vgem_gem_dumb_create(struct drm_file *file, struct drm_device *dev,



Acked-by: Laura Abbott <labb...@redhat.com>
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