[PATCH] drm/i915/gem: Avoid NULL dereference in __i915_gem_object_lock()
From: Tim Gardner <hidden>
Date: 2021-08-18 14:52:24
Also in:
dri-devel, intel-gfx, kernel-janitors, linux-media, lkml
Subsystem:
drm drivers, intel drm i915 driver (meteor lake, dg2 and older excluding poulsbo, moorestown and derivative), the rest · Maintainers:
David Airlie, Simona Vetter, Jani Nikula, Joonas Lahtinen, Rodrigo Vivi, Tvrtko Ursulin, Linus Torvalds
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 <redacted>
Cc: Daniel Vetter <redacted>
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 <redacted>
---
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; }
--
2.33.0