From 3d004f7341d4898889801ebb2ef61ffca610dd6f Mon Sep 17 00:00:00 2001 From: Simon Richter 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 commit 491adc6a0f9903c32b05f284df1148de39e8e644 upstream. 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 Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6271 Signed-off-by: Simon Richter Reviewed-by: Matthew Brost Reviewed-by: Shuicheng Lin Reviewed-by: Christian König Signed-off-by: Matthew Brost Link: https://patch.msgid.link/20251013161241.709916-1-Simon.Richter@hogyros.de Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/ttm/ttm_bo_vm.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c index 4212b8c91dd4..d69d71ed7dd9 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c @@ -421,6 +421,11 @@ int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr, if (ret) return ret; + if (!bo->resource) { + ret = -ENODATA; + goto unlock; + } + switch (bo->resource->mem_type) { case TTM_PL_SYSTEM: fallthrough; @@ -435,6 +440,7 @@ int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr, ret = -EIO; } +unlock: ttm_bo_unreserve(bo); return ret;