From f112ea910e554d58b4b39a4492b7d302f0f4204f Mon Sep 17 00:00:00 2001 From: Alexander Usyskin Date: Sun, 5 Jul 2026 18:12:59 +0300 Subject: [PATCH] mei: bus: access mei_device under device_lock on cleanup Fix couple of problems in mei_cl_bus_dev_release(): mei_cl_flush_queues() is running without lock. bus->file_list access after mei_dev_bus_put(bus) can become a use-after-free if this was the last reference to bus. Protect queues cleanup and WARN traversal by device lock there to avoid the concurrent access problems. Move WARN traversal before mei_dev_bus_put(bus). This file uses bus variable name for mei_device, adjust code of mei_cl_bus_dev_release() to use bus variable too. Cc: stable Fixes: 35e8a426b16a ("mei: bus: Check for still connected devices in mei_cl_bus_dev_release()") Reviewed-by: Menachem Adin Signed-off-by: Alexander Usyskin Link: https://patch.msgid.link/20260705151259.3054795-1-alexander.usyskin@intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/misc/mei/bus.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c index fcde082eb5e3..cfb87ab8667f 100644 --- a/drivers/misc/mei/bus.c +++ b/drivers/misc/mei/bus.c @@ -4,6 +4,7 @@ * Intel Management Engine Interface (Intel MEI) Linux driver */ +#include #include #include #include @@ -1330,15 +1331,16 @@ static void mei_dev_bus_put(struct mei_device *bus) static void mei_cl_bus_dev_release(struct device *dev) { struct mei_cl_device *cldev = to_mei_cl_device(dev); - struct mei_device *mdev = cldev->cl->dev; + struct mei_device *bus = cldev->bus; struct mei_cl *cl; - mei_cl_flush_queues(cldev->cl, NULL); - mei_me_cl_put(cldev->me_cl); - mei_dev_bus_put(cldev->bus); - - list_for_each_entry(cl, &mdev->file_list, link) - WARN_ON(cl == cldev->cl); + scoped_guard(mutex, &bus->device_lock) { + mei_cl_flush_queues(cldev->cl, NULL); + mei_me_cl_put(cldev->me_cl); + list_for_each_entry(cl, &bus->file_list, link) + WARN_ON(cl == cldev->cl); + } + mei_dev_bus_put(bus); kfree(cldev->cl); kfree(cldev);