Linux Kernel: device_lock enforcement in driver_match_device() to prevent UAF
CVE-2026-31688 Published on April 27, 2026
driver core: enforce device_lock for driver_match_device()
In the Linux kernel, the following vulnerability has been resolved:
driver core: enforce device_lock for driver_match_device()
Currently, driver_match_device() is called from three sites. One site
(__device_attach_driver) holds device_lock(dev), but the other two
(bind_store and __driver_attach) do not. This inconsistency means that
bus match() callbacks are not guaranteed to be called with the lock
held.
Fix this by introducing driver_match_device_locked(), which guarantees
holding the device lock using a scoped guard. Replace the unlocked calls
in bind_store() and __driver_attach() with this new helper. Also add a
lock assertion to driver_match_device() to enforce this guarantee.
This consistency also fixes a known race condition. The driver_override
implementation relies on the device_lock, so the missing lock led to the
use-after-free (UAF) reported in Bugzilla for buses using this field.
Stress testing the two newly locked paths for 24 hours with
CONFIG_PROVE_LOCKING and CONFIG_LOCKDEP enabled showed no UAF recurrence
and no lockdep warnings.
Products Associated with CVE-2026-31688
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Affected Versions
Linux:- Version 49b420a13ff95b449947181190b08367348e3e1b and below dc23806a7c47ec5f1293aba407fb69519f976ee0 is affected.
- Version 2.6.30 is affected.
- Before 2.6.30 is unaffected.
- Version 7.0, <= * is unaffected.