drm/xe/guc: Fix buffer overflow in steered register list allocation

Summary

In the Linux kernel, the following vulnerability has been resolved: 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) (cherry picked from commit 0a78a44f4901aa6c9263e66be7fce02282f1109f)

Timeline

1. Aug 10, 2026, 12:01 PM UTCCVE published
2. Oct 16, 2026, 3:46 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Oct 19, 2026, 8:58 PM UTCRecord last updated

Affected versions

• Linux Linux

  From b170d696c1e2226713471d810c63b1162335079f · fixed in b485bfb45555163bfa5f565d6a3415fcb3035b02; From b170d696c1e2226713471d810c63b1162335079f · fixed in a9a020f3c11eba6573b699f9cf9245a51b025ade; From b170d696c1e2226713471d810c63b1162335079f · fixed in 632ecc90e1ca5d3b6822bb4d08f84a175b6c42c0

• Linux Linux

  6.13

• KernelLinux

  From 6.13.0 · fixed in 6.18.44; From 6.19.0 · fixed in 7.1.6

References 3