This is a note to let you know that I've just added the patch titled
wireless: regulatory: fix channel disabling race condition
to the 3.4-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:
wireless-regulatory-fix-channel-disabling-race-condition.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 990de49f74e772b6db5208457b7aa712a5f4db86 Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@xxxxxxxxx>
Date: Tue, 16 Apr 2013 14:32:26 +0200
Subject: wireless: regulatory: fix channel disabling race condition
From: Johannes Berg <johannes.berg@xxxxxxxxx>
commit 990de49f74e772b6db5208457b7aa712a5f4db86 upstream.
When a full scan 2.4 and 5 GHz scan is scheduled, but then the 2.4 GHz
part of the scan disables a 5.2 GHz channel due to, e.g. receiving
country or frequency information, that 5.2 GHz channel might already
be in the list of channels to scan next. Then, when the driver checks
if it should do a passive scan, that will return false and attempt an
active scan. This is not only wrong but can also lead to the iwlwifi
device firmware crashing since it checks regulatory as well.
Fix this by not setting the channel flags to just disabled but rather
OR'ing in the disabled flag. That way, even if the race happens, the
channel will be scanned passively which is still (mostly) correct.
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/wireless/reg.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -862,7 +862,7 @@ static void handle_channel(struct wiphy
return;
REG_DBG_PRINT("Disabling freq %d MHz\n", chan->center_freq);
- chan->flags = IEEE80211_CHAN_DISABLED;
+ chan->flags |= IEEE80211_CHAN_DISABLED;
return;
}
Patches currently in stable-queue which might be from johannes.berg@xxxxxxxxx are
queue-3.4/wireless-regulatory-fix-channel-disabling-race-condition.patch
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