Coverity warns of a possible NULL dereference:

Both dma_resv_lock_interruptible() and dma_resv_lock() can return -EDEADLK. Protect against a NULL dereference by checking for NULL before saving the object pointer. This is consistent with previous checks for ww==NULL.

Addresses-Coverity: ("Dereference after null check")

Cc: stable@vger.kernel.org Fixes: 80f0b679d6f0683f23cf98a511af3e44dd509472 ("drm/i915: Add an implementation for i915_gem_ww_ctx locking, v2.") Cc: kernel-janitors@vger.kernel.org Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com Cc: Jani Nikula jani.nikula@linux.intel.com Cc: Joonas Lahtinen joonas.lahtinen@linux.intel.com Cc: Rodrigo Vivi rodrigo.vivi@intel.com Cc: David Airlie airlied@linux.ie Cc: Daniel Vetter daniel@ffwll.ch Cc: intel-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Signed-off-by: Tim Gardner tim.gardner@canonical.com --- drivers/gpu/drm/i915/gem/i915_gem_object.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h index 48112b9d76df..3391ca4f662a 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h @@ -187,7 +187,7 @@ static inline int __i915_gem_object_lock(struct drm_i915_gem_object *obj, if (ret == -EALREADY) ret = 0;

- if (ret == -EDEADLK) { + if (ret == -EDEADLK && ww) { i915_gem_object_get(obj); ww->contended = obj; }