staging: vchiq_arm: Fix possible NPR of keep-alive thread

[ Upstream commit 3db89bc6d973e2bcaa852f6409c98c228f39a926 ]

In case vchiq_platform_conn_state_changed() is never called or fails before
driver removal, ka_thread won't be a valid pointer to a task_struct. So
do the necessary checks before calling kthread_stop to avoid a crash.

Fixes: 863a756aaf49 ("staging: vc04_services: vchiq_core: Stop kthreads on vchiq module unload")
Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Link: https://lore.kernel.org/r/20250309125014.37166-3-wahrenst@gmx.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index ecf6e9635a10bc9f7b6c1cd09e2b9208618ae0be..97787002080a18aa6eedf5ed7cfeba3b3a362fbd 100644 (file)
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -1786,7 +1786,8 @@ static void vchiq_remove(struct platform_device *pdev)
        kthread_stop(mgmt->state.slot_handler_thread);
 
        arm_state = vchiq_platform_get_arm_state(&mgmt->state);
-       kthread_stop(arm_state->ka_thread);
+       if (!IS_ERR_OR_NULL(arm_state->ka_thread))
+               kthread_stop(arm_state->ka_thread);
 }
 
 static struct platform_driver vchiq_driver = {