wifi: cfg80211: cancel pmsr_free_wk in cfg80211_pmsr_wdev_down

When the nl80211 socket that originated a PMSR request is
closed, cfg80211_release_pmsr() sets the request's nl_portid
to zero and schedules pmsr_free_wk to process the abort
asynchronously. If the interface is concurrently torn down
before that work runs, cfg80211_pmsr_wdev_down() calls
cfg80211_pmsr_process_abort() directly. However, the already-
scheduled pmsr_free_wk work item remains pending and may run
after the interface has been removed from the driver. This
could cause the driver's abort_pmsr callback to operate on a
torn-down interface, leading to undefined behavior and
potential crashes.

Cancel pmsr_free_wk synchronously in cfg80211_pmsr_wdev_down()
before calling cfg80211_pmsr_process_abort(). This ensures any
pending or in-progress work is drained before interface teardown
proceeds, preventing the work from invoking the driver abort
callback after the interface is gone.

Fixes: 9bb7e0f24e ("cfg80211: add peer measurement with FTM initiator API")
Signed-off-by: Peddolla Harshavardhan Reddy <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Johannes Berg <[email protected]>

net/wireless/pmsr.c

@@ -664,6 +664,7 @@ void cfg80211_pmsr_wdev_down(struct wireless_dev *wdev)
 	}
 	spin_unlock_bh(&wdev->pmsr_lock);
 
+	cancel_work_sync(&wdev->pmsr_free_wk);
 	if (found)
 		cfg80211_pmsr_process_abort(wdev);