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c10841ca72
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>