Hello,
My static analysis tool reports a possible deadlock in the wfx driver in
Linux 5.16:
wfx_conf_tx()
mutex_lock(&wdev->conf_mutex); --> Line 225 (Lock A)
wfx_update_pm()
wait_for_completion_timeout(&wvif->set_pm_mode_complete, ...); -->
Line 3019 (Wait X)
wfx_add_interface()
mutex_lock(&wdev->conf_mutex); --> Line 737 (Lock A)
complete(&wvif->set_pm_mode_complete); --> Line 758 (Wake X)
When wfx_conf_tx() is executed, "Wait X" is performed by holding "Lock
A". If wfx_add_interface() is executed at this time, "Wake X" cannot be
performed to wake up "Wait X" in wfx_conf_tx(), because "Lock A" has
been already hold by wfx_conf_tx(), causing a possible deadlock.
I find that "Wait X" is performed with a timeout, to relieve the
possible deadlock; but I think this timeout can cause inefficient execution.
I am not quite sure whether this possible problem is real and how to fix
it if it is real.
Any feedback would be appreciated, thanks :)
Best wishes,
Jia-Ju Bai
