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authorLuciano Coelho <coelho@ti.com>2011-06-30 08:32:41 +0300
committerJohn W. Linville <linville@tuxdriver.com>2011-07-05 14:42:36 -0400
commitc10841ca722a0bc960dc541c51582773f9a24f98 (patch)
treef1e5901db0a530cfd4008f718a908a86bddcb333 /net/wireless/scan.c
parent37000b305bff81bb1ee2f7f37b1319b670a08f76 (diff)
downloadlinux-c10841ca722a0bc960dc541c51582773f9a24f98.tar.bz2
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/scan.c')
-rw-r--r--net/wireless/scan.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 7a6c67667d70..ae0c2256ba3b 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -100,14 +100,14 @@ void __cfg80211_sched_scan_results(struct work_struct *wk)
rdev = container_of(wk, struct cfg80211_registered_device,
sched_scan_results_wk);
- cfg80211_lock_rdev(rdev);
+ mutex_lock(&rdev->sched_scan_mtx);
/* we don't have sched_scan_req anymore if the scan is stopping */
if (rdev->sched_scan_req)
nl80211_send_sched_scan_results(rdev,
rdev->sched_scan_req->dev);
- cfg80211_unlock_rdev(rdev);
+ mutex_unlock(&rdev->sched_scan_mtx);
}
void cfg80211_sched_scan_results(struct wiphy *wiphy)
@@ -123,9 +123,9 @@ void cfg80211_sched_scan_stopped(struct wiphy *wiphy)
{
struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);
- cfg80211_lock_rdev(rdev);
+ mutex_lock(&rdev->sched_scan_mtx);
__cfg80211_stop_sched_scan(rdev, true);
- cfg80211_unlock_rdev(rdev);
+ mutex_unlock(&rdev->sched_scan_mtx);
}
EXPORT_SYMBOL(cfg80211_sched_scan_stopped);
@@ -135,7 +135,7 @@ int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev,
int err;
struct net_device *dev;
- ASSERT_RDEV_LOCK(rdev);
+ lockdep_assert_held(&rdev->sched_scan_mtx);
if (!rdev->sched_scan_req)
return 0;