5.0-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Biggers ebiggers@google.com
commit 36b6c9ed45afe89045973e8dee1b004dd5372d40 upstream.
If drm_gem_handle_create() fails in vkms_gem_create(), then the vkms_gem_object is freed twice: once when the reference is dropped by drm_gem_object_put_unlocked(), and again by the extra calls to drm_gem_object_release() and kfree().
Fix it by skipping the second release and free.
This bug was originally found in the vgem driver by syzkaller using fault injection, but I noticed it's also present in the vkms driver.
Fixes: 559e50fd34d1 ("drm/vkms: Add dumb operations") Cc: Rodrigo Siqueira rodrigosiqueiramelo@gmail.com Cc: Haneen Mohammed hamohammed.sa@gmail.com Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Chris Wilson chris@chris-wilson.co.uk Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers ebiggers@google.com Reviewed-by: Chris Wilson chris@chris-wilson.co.uk Reviewed-by: Rodrigo Siqueira rodrigosiqueiramelo@gmail.com Signed-off-by: Rodrigo Siqueira rodrigosiqueiramelo@gmail.com Link: https://patchwork.freedesktop.org/patch/msgid/20190226220858.214438-1-ebigge... Signed-off-by: Maxime Ripard maxime.ripard@bootlin.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/vkms/vkms_gem.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
--- a/drivers/gpu/drm/vkms/vkms_gem.c +++ b/drivers/gpu/drm/vkms/vkms_gem.c @@ -111,11 +111,8 @@ struct drm_gem_object *vkms_gem_create(s
ret = drm_gem_handle_create(file, &obj->gem, handle); drm_gem_object_put_unlocked(&obj->gem); - if (ret) { - drm_gem_object_release(&obj->gem); - kfree(obj); + if (ret) return ERR_PTR(ret); - }
return &obj->gem; }