From: Rob Clark robdclark@chromium.org
commit 7057a8f126f14f14b040faecfa220fd27c6c2f85 upstream.
A userspace with multiple threads racing I915_GEM_SET_TILING to set the tiling to I915_TILING_NONE could trigger a double free of the bit_17 bitmask. (Or conversely leak memory on the transition to tiled.) Move allocation/free'ing of the bitmask within the section protected by the obj lock.
Signed-off-by: Rob Clark robdclark@chromium.org Fixes: 2850748ef876 ("drm/i915: Pull i915_vma_pin under the vm->mutex") Cc: stable@vger.kernel.org # v5.5+ [tursulin: Correct fixes tag and added cc stable.] Reviewed-by: Tvrtko Ursulin tvrtko.ursulin@intel.com Signed-off-by: Tvrtko Ursulin tvrtko.ursulin@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20230127200550.3531984-1-robdc... (cherry picked from commit 10e0cbaaf1104f449d695c80bcacf930dcd3c42e) Signed-off-by: Rodrigo Vivi rodrigo.vivi@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/i915/gem/i915_gem_tiling.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
--- a/drivers/gpu/drm/i915/gem/i915_gem_tiling.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_tiling.c @@ -305,10 +305,6 @@ i915_gem_object_set_tiling(struct drm_i9 spin_unlock(&obj->vma.lock);
obj->tiling_and_stride = tiling | stride; - i915_gem_object_unlock(obj); - - /* Force the fence to be reacquired for GTT access */ - i915_gem_object_release_mmap_gtt(obj);
/* Try to preallocate memory required to save swizzling on put-pages */ if (i915_gem_object_needs_bit17_swizzle(obj)) { @@ -321,6 +317,11 @@ i915_gem_object_set_tiling(struct drm_i9 obj->bit_17 = NULL; }
+ i915_gem_object_unlock(obj); + + /* Force the fence to be reacquired for GTT access */ + i915_gem_object_release_mmap_gtt(obj); + return 0; }