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authorLuciano Coelho <coelho@ti.com>2011-06-30 09:32:41 +0400
committerJohn W. Linville <linville@tuxdriver.com>2011-07-05 22:42:36 +0400
commitc10841ca722a0bc960dc541c51582773f9a24f98 (patch)
treef1e5901db0a530cfd4008f718a908a86bddcb333 /net/wireless/core.c
parent37000b305bff81bb1ee2f7f37b1319b670a08f76 (diff)
downloadlinux-c10841ca722a0bc960dc541c51582773f9a24f98.tar.xz
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.c12
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