]> www.infradead.org Git - users/jedix/linux-maple.git/commit
drm/ttm: Fix a NULL pointer dereference
authorThomas Hellström <thomas.hellstrom@linux.intel.com>
Tue, 7 Mar 2023 14:46:15 +0000 (15:46 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 22 Mar 2023 12:33:56 +0000 (13:33 +0100)
commit9ba1720f6c4a0f13c3f3cb5c28132ee75555d04f
tree148745f51b569ac92e25e6e52b9f62c5a75e2597
parent20d305f79c4e1f0d11496062c8793031fc3837c5
drm/ttm: Fix a NULL pointer dereference

commit 9a9a8fe26751334b7739193a94eba741073b8a55 upstream.

The LRU mechanism may look up a resource in the process of being removed
from an object. The locking rules here are a bit unclear but it looks
currently like res->bo assignment is protected by the LRU lock, whereas
bo->resource is protected by the object lock, while *clearing* of
bo->resource is also protected by the LRU lock. This means that if
we check that bo->resource points to the LRU resource under the LRU
lock we should be safe.
So perform that check before deciding to swap out a bo. That avoids
dereferencing a NULL bo->resource in ttm_bo_swapout().

Fixes: 6a9b02899402 ("drm/ttm: move the LRU into resource handling v4")
Cc: Christian König <christian.koenig@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Philip Yang <Philip.Yang@amd.com>
Cc: Qiang Yu <qiang.yu@amd.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Nirmoy Das <nirmoy.das@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>
Cc: Anshuman Gupta <anshuman.gupta@intel.com>
Cc: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v5.19+
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230307144621.10748-2-thomas.hellstrom@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/gpu/drm/ttm/ttm_device.c