From 1d8c0557927e6d69cb6341b7792f882412cfccff Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= Date: Wed, 26 Mar 2025 09:05:48 +0100 Subject: [PATCH] drm/xe/svm: Fix a potential bo UAF MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If drm_gpusvm_migrate_to_devmem() succeeds, if a cpu access happens to the range the bo may be freed before xe_bo_unlock(), causing a UAF. Since the reference is transferred, use xe_svm_devmem_release() to release the reference on drm_gpusvm_migrate_to_devmem() failure, and hold a local reference to protect the UAF. Fixes: 2f118c949160 ("drm/xe: Add SVM VRAM migration") Signed-off-by: Thomas Hellström Reviewed-by: Matthew Brost Link: https://lore.kernel.org/r/20250326080551.40201-3-thomas.hellstrom@linux.intel.com (cherry picked from commit c9db07cab766b665c8fa1184649cef452f448dc8) Signed-off-by: Lucas De Marchi --- drivers/gpu/drm/xe/xe_svm.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c index 3e829c87d7b4..f8c128524d9f 100644 --- a/drivers/gpu/drm/xe/xe_svm.c +++ b/drivers/gpu/drm/xe/xe_svm.c @@ -696,11 +696,14 @@ static int xe_svm_alloc_vram(struct xe_vm *vm, struct xe_tile *tile, list_for_each_entry(block, blocks, link) block->private = vr; + xe_bo_get(bo); err = drm_gpusvm_migrate_to_devmem(&vm->svm.gpusvm, &range->base, &bo->devmem_allocation, ctx); - xe_bo_unlock(bo); if (err) - xe_bo_put(bo); /* Creation ref */ + xe_svm_devmem_release(&bo->devmem_allocation); + + xe_bo_unlock(bo); + xe_bo_put(bo); unlock: mmap_read_unlock(mm);