From: Duoming Zhou Date: Wed, 17 Dec 2025 03:00:17 +0000 (+0800) Subject: Input: alps - fix use-after-free bugs caused by dev3_register_work X-Git-Tag: v6.19-rc2~2^2~4 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bf40644ef8c8a288742fa45580897ed0e0289474;p=thirdparty%2Flinux.git Input: alps - fix use-after-free bugs caused by dev3_register_work The dev3_register_work delayed work item is initialized within alps_reconnect() and scheduled upon receipt of the first bare PS/2 packet from an external PS/2 device connected to the ALPS touchpad. During device detachment, the original implementation calls flush_workqueue() in psmouse_disconnect() to ensure completion of dev3_register_work. However, the flush_workqueue() in psmouse_disconnect() only blocks and waits for work items that were already queued to the workqueue prior to its invocation. Any work items submitted after flush_workqueue() is called are not included in the set of tasks that the flush operation awaits. This means that after flush_workqueue() has finished executing, the dev3_register_work could still be scheduled. Although the psmouse state is set to PSMOUSE_CMD_MODE in psmouse_disconnect(), the scheduling of dev3_register_work remains unaffected. The race condition can occur as follows: CPU 0 (cleanup path) | CPU 1 (delayed work) psmouse_disconnect() | psmouse_set_state() | flush_workqueue() | alps_report_bare_ps2_packet() alps_disconnect() | psmouse_queue_work() kfree(priv); // FREE | alps_register_bare_ps2_mouse() | priv = container_of(work...); // USE | priv->dev3 // USE Add disable_delayed_work_sync() in alps_disconnect() to ensure that dev3_register_work is properly canceled and prevented from executing after the alps_data structure has been deallocated. This bug is identified by static analysis. Fixes: 04aae283ba6a ("Input: ALPS - do not mix trackstick and external PS/2 mouse data") Cc: stable@kernel.org Signed-off-by: Duoming Zhou Link: https://patch.msgid.link/b57b0a9ccca51a3f06be141bfc02b9ffe69d1845.1765939397.git.duoming@zju.edu.cn Signed-off-by: Dmitry Torokhov --- diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c index d0cb9fb948218..df8953a5196e1 100644 --- a/drivers/input/mouse/alps.c +++ b/drivers/input/mouse/alps.c @@ -2975,6 +2975,7 @@ static void alps_disconnect(struct psmouse *psmouse) psmouse_reset(psmouse); timer_shutdown_sync(&priv->timer); + disable_delayed_work_sync(&priv->dev3_register_work); if (priv->dev2) input_unregister_device(priv->dev2); if (!IS_ERR_OR_NULL(priv->dev3))