The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 491adc6a0f9903c32b05f284df1148de39e8e644 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2026010549-periscope-recluse-8408@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 491adc6a0f9903c32b05f284df1148de39e8e644 Mon Sep 17 00:00:00 2001 From: Simon Richter Simon.Richter@hogyros.de Date: Tue, 14 Oct 2025 01:11:33 +0900 Subject: [PATCH] drm/ttm: Avoid NULL pointer deref for evicted BOs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

It is possible for a BO to exist that is not currently associated with a resource, e.g. because it has been evicted.

When devcoredump tries to read the contents of all BOs for dumping, we need to expect this as well -- in this case, ENODATA is recorded instead of the buffer contents.

Fixes: 7d08df5d0bd3 ("drm/ttm: Add ttm_bo_access") Fixes: 09ac4fcb3f25 ("drm/ttm: Implement vm_operations_struct.access v2") Cc: stable stable@kernel.org Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6271 Signed-off-by: Simon Richter Simon.Richter@hogyros.de Reviewed-by: Matthew Brost matthew.brost@intel.com Reviewed-by: Shuicheng Lin shuicheng.lin@intel.com Reviewed-by: Christian König christian.koenig@amd.com Signed-off-by: Matthew Brost matthew.brost@intel.com Link: https://patch.msgid.link/20251013161241.709916-1-Simon.Richter@hogyros.de

diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c index b47020fca199..e6abc7b40b18 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c @@ -434,6 +434,11 @@ int ttm_bo_access(struct ttm_buffer_object *bo, unsigned long offset, if (ret) return ret;

+ if (!bo->resource) { + ret = -ENODATA; + goto unlock; + } + switch (bo->resource->mem_type) { case TTM_PL_SYSTEM: fallthrough; @@ -448,6 +453,7 @@ int ttm_bo_access(struct ttm_buffer_object *bo, unsigned long offset, ret = -EIO; }

+unlock: ttm_bo_unreserve(bo);

return ret;