This is a note to let you know that I've just added the patch titled
mac80211: fix scheduled scan rtnl deadlock
to the 3.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mac80211-fix-scheduled-scan-rtnl-deadlock.patch
and it can be found in the queue-3.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 18db594a1005d908d995a2fc8f5a7bf4286fdca0 Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@xxxxxxxxx>
Date: Wed, 6 Nov 2013 10:34:36 +0100
Subject: mac80211: fix scheduled scan rtnl deadlock
From: Johannes Berg <johannes.berg@xxxxxxxxx>
commit 18db594a1005d908d995a2fc8f5a7bf4286fdca0 upstream.
When changing cfg80211 to use RTNL locking, this caused a
deadlock in mac80211 as it calls cfg80211_sched_scan_stopped()
from a work item that's on a workqueue that is flushed with
the RTNL held.
Fix this by simply using schedule_work(), the work only needs
to finish running before the wiphy is unregistered, no other
synchronisation (e.g. with suspend) is really required since
for suspend userspace is already blocked anyway when we flush
the workqueue so will only pick up the event after resume.
Fixes: 5fe231e87372 ("cfg80211: vastly simplify locking")
Reported-and-tested-by: Eliad Peller <eliadx.peller@xxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/mac80211/main.c | 1 +
net/mac80211/scan.c | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -1047,6 +1047,7 @@ void ieee80211_unregister_hw(struct ieee
cancel_work_sync(&local->restart_work);
cancel_work_sync(&local->reconfig_filter);
+ flush_work(&local->sched_scan_stopped_work);
ieee80211_clear_tx_pending(local);
rate_control_deinitialize(local);
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -1089,6 +1089,6 @@ void ieee80211_sched_scan_stopped(struct
trace_api_sched_scan_stopped(local);
- ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
+ schedule_work(&local->sched_scan_stopped_work);
}
EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
Patches currently in stable-queue which might be from johannes.berg@xxxxxxxxx are
queue-3.12/mac80211-fix-scheduled-scan-rtnl-deadlock.patch
queue-3.12/cfg80211-disable-5-10-mhz-support-for-all-drivers.patch
queue-3.12/iwlwifi-pcie-fix-interrupt-coalescing-for-7260-3160.patch
queue-3.12/revert-mac80211-allow-disable-power-save-in-mesh.patch
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