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/sme.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'net/wireless/sme.c') diff --git a/net/wireless/sme.c b/net/wireless/sme.c index f432bd3755b1..09d994d192ff 100644 --- a/net/wireless/sme.c +++ b/net/wireless/sme.c @@ -85,6 +85,7 @@ static int cfg80211_conn_scan(struct wireless_dev *wdev) ASSERT_RTNL(); ASSERT_RDEV_LOCK(rdev); ASSERT_WDEV_LOCK(wdev); + lockdep_assert_held(&rdev->sched_scan_mtx); if (rdev->scan_req) return -EBUSY; @@ -320,11 +321,9 @@ void cfg80211_sme_scan_done(struct net_device *dev) { struct wireless_dev *wdev = dev->ieee80211_ptr; - mutex_lock(&wiphy_to_dev(wdev->wiphy)->devlist_mtx); wdev_lock(wdev); __cfg80211_sme_scan_done(dev); wdev_unlock(wdev); - mutex_unlock(&wiphy_to_dev(wdev->wiphy)->devlist_mtx); } void cfg80211_sme_rx_auth(struct net_device *dev, @@ -924,9 +923,12 @@ int cfg80211_connect(struct cfg80211_registered_device *rdev, int err; mutex_lock(&rdev->devlist_mtx); + /* might request scan - scan_mtx -> wdev_mtx dependency */ + mutex_lock(&rdev->sched_scan_mtx); wdev_lock(dev->ieee80211_ptr); err = __cfg80211_connect(rdev, dev, connect, connkeys, NULL); wdev_unlock(dev->ieee80211_ptr); + mutex_unlock(&rdev->sched_scan_mtx); mutex_unlock(&rdev->devlist_mtx); return err; -- cgit v1.2.1 From 90e0970f8788cef2c8f5183af5a98f4f94600faf Mon Sep 17 00:00:00 2001 From: Artem Savkov Date: Sat, 30 Mar 2013 21:20:14 +0400 Subject: cfg80211: sched_scan_mtx lock in cfg80211_conn_work() Introduced in f9f475292dbb0e7035fb6661d1524761ea0888d9 ("cfg80211: always check for scan end on P2P device") cfg80211_conn_scan() which requires sched_scan_mtx to be held can be called from cfg80211_conn_work(). Without this we are hitting multiple warnings like the following: WARNING: at net/wireless/sme.c:88 cfg80211_conn_scan+0x1dc/0x3a0 [cfg80211]() Hardware name: 0578A21 Modules linked in: ... Pid: 620, comm: kworker/3:1 Not tainted 3.9.0-rc4-next-20130328+ #326 Call Trace: [] warn_slowpath_common+0x72/0xa0 [] warn_slowpath_null+0x22/0x30 [] cfg80211_conn_scan+0x1dc/0x3a0 [cfg80211] [] cfg80211_conn_do_work+0x94/0x380 [cfg80211] [] cfg80211_conn_work+0xa2/0x130 [cfg80211] [] process_one_work+0x198/0x450 Signed-off-by: Artem Savkov Signed-off-by: Johannes Berg --- net/wireless/sme.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/wireless/sme.c') diff --git a/net/wireless/sme.c b/net/wireless/sme.c index 09d994d192ff..482c70e70127 100644 --- a/net/wireless/sme.c +++ b/net/wireless/sme.c @@ -224,6 +224,7 @@ void cfg80211_conn_work(struct work_struct *work) rtnl_lock(); cfg80211_lock_rdev(rdev); mutex_lock(&rdev->devlist_mtx); + mutex_lock(&rdev->sched_scan_mtx); list_for_each_entry(wdev, &rdev->wdev_list, list) { wdev_lock(wdev); @@ -248,6 +249,7 @@ void cfg80211_conn_work(struct work_struct *work) wdev_unlock(wdev); } + mutex_unlock(&rdev->sched_scan_mtx); mutex_unlock(&rdev->devlist_mtx); cfg80211_unlock_rdev(rdev); rtnl_unlock(); -- cgit v1.2.1