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authorJohannes Berg <johannes.berg@intel.com>2013-04-16 14:32:26 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-05-07 19:57:27 -0700
commitd2a51f02ccc6fac30f8cdb7e5f2791b2fe43d129 (patch)
tree629b25263b78ed748b92ff20abb596e0d9566be1
parentcfb0a900641f0d5c84bc1e68bbf3e312ae37c549 (diff)
wireless: regulatory: fix channel disabling race condition
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@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/wireless/reg.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index aec54df6196d..f6cc5b40f2e7 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -852,7 +852,7 @@ static void handle_channel(struct wiphy *wiphy,
return;
REG_DBG_PRINT("Disabling freq %d MHz\n", chan->center_freq);
- chan->flags = IEEE80211_CHAN_DISABLED;
+ chan->flags |= IEEE80211_CHAN_DISABLED;
return;
}