From: Tejas Upadhyay Date: Fri, 12 Jun 2026 07:04:02 +0000 (+0530) Subject: drm/xe/guc: Fix buffer overflow in steered register list allocation X-Git-Tag: v7.2-rc1~10^2~2^2~1 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=632ecc90e1ca5d3b6822bb4d08f84a175b6c42c0;p=thirdparty%2Flinux.git drm/xe/guc: Fix buffer overflow in steered register list allocation The size calculation for the steered register extarray uses only the geometry DSS mask (g_dss_mask) to determine the number of entries to allocate: total = bitmap_weight(gt->fuse_topo.g_dss_mask, ...) * steer_reg_num; However, the filling loop uses for_each_dss_steering(), which iterates over for_each_dss(), defined as the union of g_dss_mask and c_dss_mask (geometry + compute DSS). On platforms with compute-only DSS bits, the loop writes past the allocated buffer, corrupting adjacent slab objects. This manifests as list_del corruption and SLUB redzone overwrites during drm_managed_release on device unbind, since the overflow corrupts the drmres list_head of neighboring allocations. Fix by computing the allocation size using the union of both DSS masks, matching the iteration pattern of for_each_dss_steering(). -- v2: - use bitmap_weighted_or() (Zhanjun) Fixes: b170d696c1e2 ("drm/xe/guc: Add XE_LP steered register lists") Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/8049 Cc: Zhanjun Dong Cc: stable@vger.kernel.org Assisted-by: GitHub-Copilot:claude-opus-4.6 Reviewed-by: Zhanjun Dong Link: https://patch.msgid.link/20260612070401.543305-2-tejas.upadhyay@intel.com Signed-off-by: Tejas Upadhyay (cherry picked from commit 0a78a44f4901aa6c9263e66be7fce02282f1109f) Signed-off-by: Matthew Brost --- diff --git a/drivers/gpu/drm/xe/xe_guc_capture.c b/drivers/gpu/drm/xe/xe_guc_capture.c index 21f7caf9ea084..1a019137ddf42 100644 --- a/drivers/gpu/drm/xe/xe_guc_capture.c +++ b/drivers/gpu/drm/xe/xe_guc_capture.c @@ -461,8 +461,14 @@ static void guc_capture_alloc_steered_lists(struct xe_guc *guc) if (!list || guc->capture->extlists) return; - total = bitmap_weight(gt->fuse_topo.g_dss_mask, sizeof(gt->fuse_topo.g_dss_mask) * 8) * - guc_capture_get_steer_reg_num(guc_to_xe(guc)); + { + xe_dss_mask_t all_dss; + + total = bitmap_weighted_or(all_dss, gt->fuse_topo.g_dss_mask, + gt->fuse_topo.c_dss_mask, + XE_MAX_DSS_FUSE_BITS) * + guc_capture_get_steer_reg_num(guc_to_xe(guc)); + } if (!total) return;