diff options
author | Johannes Berg <johannes@sipsolutions.net> | 2009-11-22 11:28:41 (GMT) |
---|---|---|
committer | John W. Linville <linville@tuxdriver.com> | 2009-11-30 18:55:51 (GMT) |
commit | 827d42c9ac91ddd728e4f4a31fefb906ef2ceff7 (patch) | |
tree | e29371d79d63d0a3ec2cb6d010b71147853fc771 /include/net/mac80211.h | |
parent | 4253119acf412fd686ef4bd8749b5a4d70ea3a51 (diff) | |
download | linux-fsl-qoriq-827d42c9ac91ddd728e4f4a31fefb906ef2ceff7.tar.xz |
mac80211: fix spurious delBA handling
Lennert Buytenhek noticed that delBA handling in mac80211
was broken and has remotely triggerable problems, some of
which are due to some code shuffling I did that ended up
changing the order in which things were done -- this was
commit d75636ef9c1af224f1097941879d5a8db7cd04e5
Author: Johannes Berg <johannes@sipsolutions.net>
Date: Tue Feb 10 21:25:53 2009 +0100
mac80211: RX aggregation: clean up stop session
and other parts were already present in the original
commit d92684e66091c0f0101819619b315b4bb8b5bcc5
Author: Ron Rindjunsky <ron.rindjunsky@intel.com>
Date: Mon Jan 28 14:07:22 2008 +0200
mac80211: A-MPDU Tx add delBA from recipient support
The first problem is that I moved a BUG_ON before various
checks -- thereby making it possible to hit. As the comment
indicates, the BUG_ON can be removed since the ampdu_action
callback must already exist when the state is != IDLE.
The second problem isn't easily exploitable but there's a
race condition due to unconditionally setting the state to
OPERATIONAL when a delBA frame is received, even when no
aggregation session was ever initiated. All the drivers
accept stopping the session even then, but that opens a
race window where crashes could happen before the driver
accepts it. Right now, a WARN_ON may happen with non-HT
drivers, while the race opens only for HT drivers.
For this case, there are two things necessary to fix it:
1) don't process spurious delBA frames, and be more careful
about the session state; don't drop the lock
2) HT drivers need to be prepared to handle a session stop
even before the session was really started -- this is
true for all drivers (that support aggregation) but
iwlwifi which can be fixed easily. The other HT drivers
(ath9k and ar9170) are behaving properly already.
Reported-by: Lennert Buytenhek <buytenh@marvell.com>
Cc: stable@kernel.org
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'include/net/mac80211.h')
-rw-r--r-- | include/net/mac80211.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/net/mac80211.h b/include/net/mac80211.h index c75b960..998c30f 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -1283,6 +1283,12 @@ enum ieee80211_filter_flags { * * These flags are used with the ampdu_action() callback in * &struct ieee80211_ops to indicate which action is needed. + * + * Note that drivers MUST be able to deal with a TX aggregation + * session being stopped even before they OK'ed starting it by + * calling ieee80211_start_tx_ba_cb(_irqsafe), because the peer + * might receive the addBA frame and send a delBA right away! + * * @IEEE80211_AMPDU_RX_START: start Rx aggregation * @IEEE80211_AMPDU_RX_STOP: stop Rx aggregation * @IEEE80211_AMPDU_TX_START: start Tx aggregation |