]> git.ipfire.org Git - thirdparty/kernel/linux.git/commit
driver core: enforce device_lock for driver_match_device()
authorGui-Dong Han <hanguidong02@gmail.com>
Tue, 13 Jan 2026 16:28:43 +0000 (00:28 +0800)
committerDanilo Krummrich <dakr@kernel.org>
Fri, 16 Jan 2026 11:40:58 +0000 (12:40 +0100)
commitdc23806a7c47ec5f1293aba407fb69519f976ee0
tree71edf6fa646dc2cc50a105a1da96598e12b622c4
parenta995fe1a3aa78b7d06cc1cc7b6b8436c5e93b07f
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.

Cc: stable@vger.kernel.org
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220789
Suggested-by: Qiu-ji Chen <chenqiuji666@gmail.com>
Signed-off-by: Gui-Dong Han <hanguidong02@gmail.com>
Fixes: 49b420a13ff9 ("driver core: check bus->match without holding device lock")
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Link: https://patch.msgid.link/20260113162843.12712-1-hanguidong02@gmail.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
drivers/base/base.h
drivers/base/bus.c
drivers/base/dd.c