CVE-2026-68429
Published: August 14, 2026Last modified: August 14, 2026
Description
In the Linux kernel, the following vulnerability has been resolved: drm/dp_mst: Handle torn-down topology gracefully in drm_dp_mst_topology_queue_probe() A hotplug or link-loss event can tear down the MST topology (setting mgr->mst_state = false and mgr->mst_primary = NULL) concurrently with a caller invoking drm_dp_mst_topology_queue_probe(). Since the check is already performed under mgr->lock, the condition is not a programming error but a valid race -- the topology was valid when the caller decided to call this function, but was torn down before the lock was acquired. Replace the drm_WARN_ON() with a graceful early return. This eliminates spurious kernel warnings and the resulting compositor crashes observed when connecting/disconnecting DP MST monitors, while keeping the correct behavior of doing nothing when MST is not active. A drm_dbg_mst() trace is added so the skipped probe remains observable under MST debug logging. The existing WARN_ON(mgr->mst_primary) in drm_dp_mst_topology_mgr_set_mst() already catches the case where the topology is initialized twice, so no diagnostic coverage is lost.
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Not affected (6.1.33-r0) |
| 25 LTS | linux-lts | Fixed (6.12.103-r0) | |
| Stream | linux-lts | Fixed (6.18.43-r0) |
References
- https://git.kernel.org/stable/c/4ed6d08c4a59ee6a8cb806347f6d9873de5d229e
- https://git.kernel.org/stable/c/613059875958e7b217b250ed14c3b189f9488421
- https://git.kernel.org/stable/c/8c6d84a54823cd839e6ce22af559925f1320c310
- https://git.kernel.org/stable/c/afdff9103818656627920c21822e48a6dae2906f
- https://git.kernel.org/stable/c/b1d05cc61dfa6c4bd5e67855bec6a03e955f512d