From f9f475292dbb0e7035fb6661d1524761ea0888d9 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 19 Mar 2013 15:04:07 +0100 Subject: cfg80211: always check for scan end on P2P device If a P2P device wdev is removed while it has a scan, then the scan completion might crash later as it is already freed by that time. To avoid the crash always check the scan completion when the P2P device is being removed for some reason. If the driver already canceled it, don't want and free it, otherwise warn and leak it to avoid later crashes. In order to do this, locking needs to be changed away from the rdev mutex (which can't always be guaranteed). For now, use the sched_scan_mtx instead, I'll rename it to just scan_mtx in a later patch. Signed-off-by: Johannes Berg --- net/wireless/scan.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'net/wireless/scan.c') diff --git a/net/wireless/scan.c b/net/wireless/scan.c index e93bd31d23bb..fd99ea495b7e 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -169,7 +169,7 @@ void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev, bool leak) union iwreq_data wrqu; #endif - ASSERT_RDEV_LOCK(rdev); + lockdep_assert_held(&rdev->sched_scan_mtx); request = rdev->scan_req; @@ -230,9 +230,9 @@ void __cfg80211_scan_done(struct work_struct *wk) rdev = container_of(wk, struct cfg80211_registered_device, scan_done_wk); - cfg80211_lock_rdev(rdev); + mutex_lock(&rdev->sched_scan_mtx); ___cfg80211_scan_done(rdev, false); - cfg80211_unlock_rdev(rdev); + mutex_unlock(&rdev->sched_scan_mtx); } void cfg80211_scan_done(struct cfg80211_scan_request *request, bool aborted) @@ -1062,6 +1062,7 @@ int cfg80211_wext_siwscan(struct net_device *dev, if (IS_ERR(rdev)) return PTR_ERR(rdev); + mutex_lock(&rdev->sched_scan_mtx); if (rdev->scan_req) { err = -EBUSY; goto out; @@ -1168,6 +1169,7 @@ int cfg80211_wext_siwscan(struct net_device *dev, dev_hold(dev); } out: + mutex_unlock(&rdev->sched_scan_mtx); kfree(creq); cfg80211_unlock_rdev(rdev); return err; -- cgit v1.2.3