6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Duoming Zhou duoming@zju.edu.cn
commit bf40644ef8c8a288742fa45580897ed0e0289474 upstream.
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 duoming@zju.edu.cn Link: https://patch.msgid.link/b57b0a9ccca51a3f06be141bfc02b9ffe69d1845.1765939397... Signed-off-by: Dmitry Torokhov dmitry.torokhov@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/input/mouse/alps.c | 1 + 1 file changed, 1 insertion(+)
--- a/drivers/input/mouse/alps.c +++ b/drivers/input/mouse/alps.c @@ -2977,6 +2977,7 @@ static void alps_disconnect(struct psmou
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))