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| author | Luciano Coelho <coelho@ti.com> | 2011-06-30 07:32:41 +0200 |
|---|---|---|
| committer | John W. Linville <linville@tuxdriver.com> | 2011-07-05 20:42:36 +0200 |
| commit | c10841ca722a0bc960dc541c51582773f9a24f98 (patch) | |
| tree | f1e5901db0a530cfd4008f718a908a86bddcb333 /net/wireless/core.c | |
| parent | ath5k: fix incorrect use of drvdata in PCI suspend/resume code (diff) | |
| download | linux-c10841ca722a0bc960dc541c51582773f9a24f98.tar.xz linux-c10841ca722a0bc960dc541c51582773f9a24f98.zip | |
cfg80211: fix deadlock with rfkill/sched_scan by adding new mutex
There was a deadlock when rfkill-blocking a wireless interface,
because we were locking the rdev mutex on NETDEV_GOING_DOWN to stop
sched_scans that were eventually running. The rfkill block code was
already holding a mutex under rdev:
kernel: =======================================================
kernel: [ INFO: possible circular locking dependency detected ]
kernel: 3.0.0-rc1-00049-g1fa7b6a #57
kernel: -------------------------------------------------------
kernel: kworker/0:1/4525 is trying to acquire lock:
kernel: (&rdev->mtx){+.+.+.}, at: [<ffffffff8164c831>] cfg80211_netdev_notifier_call+0x131/0x5b0
kernel:
kernel: but task is already holding lock:
kernel: (&rdev->devlist_mtx){+.+.+.}, at: [<ffffffff8164dcef>] cfg80211_rfkill_set_block+0x4f/0xa0
kernel:
kernel: which lock already depends on the new lock.
To fix this, add a new mutex specifically for sched_scan, to protect
the sched_scan_req element in the rdev struct, instead of using the
global rdev mutex.
Reported-by: Duane Griffin <duaneg@dghda.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'net/wireless/core.c')
| -rw-r--r-- | net/wireless/core.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/net/wireless/core.c b/net/wireless/core.c index c22ef3492ee6..880dbe2e6f94 100644 --- a/net/wireless/core.c +++ b/net/wireless/core.c @@ -366,6 +366,7 @@ struct wiphy *wiphy_new(const struct cfg80211_ops *ops, int sizeof_priv) mutex_init(&rdev->mtx); mutex_init(&rdev->devlist_mtx); + mutex_init(&rdev->sched_scan_mtx); INIT_LIST_HEAD(&rdev->netdev_list); spin_lock_init(&rdev->bss_lock); INIT_LIST_HEAD(&rdev->bss_list); @@ -701,6 +702,7 @@ void cfg80211_dev_free(struct cfg80211_registered_device *rdev) rfkill_destroy(rdev->rfkill); mutex_destroy(&rdev->mtx); mutex_destroy(&rdev->devlist_mtx); + mutex_destroy(&rdev->sched_scan_mtx); list_for_each_entry_safe(scan, tmp, &rdev->bss_list, list) cfg80211_put_bss(&scan->pub); cfg80211_rdev_free_wowlan(rdev); @@ -737,12 +739,16 @@ static void wdev_cleanup_work(struct work_struct *work) ___cfg80211_scan_done(rdev, true); } + cfg80211_unlock_rdev(rdev); + + mutex_lock(&rdev->sched_scan_mtx); + if (WARN_ON(rdev->sched_scan_req && rdev->sched_scan_req->dev == wdev->netdev)) { __cfg80211_stop_sched_scan(rdev, false); } - cfg80211_unlock_rdev(rdev); + mutex_unlock(&rdev->sched_scan_mtx); mutex_lock(&rdev->devlist_mtx); rdev->opencount--; @@ -830,9 +836,9 @@ static int cfg80211_netdev_notifier_call(struct notifier_block * nb, break; case NL80211_IFTYPE_P2P_CLIENT: case NL80211_IFTYPE_STATION: - cfg80211_lock_rdev(rdev); + mutex_lock(&rdev->sched_scan_mtx); __cfg80211_stop_sched_scan(rdev, false); - cfg80211_unlock_rdev(rdev); + mutex_unlock(&rdev->sched_scan_mtx); wdev_lock(wdev); #ifdef CONFIG_CFG80211_WEXT |