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由 Johannes Berg 提交于
Joseph Nahmias reported, in http://bugs.debian.org/562016, that he was getting the following warning (with some log around the issue): ath0: direct probe to AP 00:11:95:77:e0:b0 (try 1) ath0: direct probe responded ath0: authenticate with AP 00:11:95:77:e0:b0 (try 1) ath0: authenticated ath0: associate with AP 00:11:95:77:e0:b0 (try 1) ath0: deauthenticating from 00:11:95:77:e0:b0 by local choice (reason=3) ath0: direct probe to AP 00:11:95:77:e0:b0 (try 1) ath0: RX AssocResp from 00:11:95:77:e0:b0 (capab=0x421 status=0 aid=2) ath0: associated ------------[ cut here ]------------ WARNING: at net/wireless/mlme.c:97 cfg80211_send_rx_assoc+0x14d/0x152 [cfg80211]() Hardware name: 7658CTO ... Pid: 761, comm: phy0 Not tainted 2.6.32-trunk-686 #1 Call Trace: [<c1030a5d>] ? warn_slowpath_common+0x5e/0x8a [<c1030a93>] ? warn_slowpath_null+0xa/0xc [<f86cafc7>] ? cfg80211_send_rx_assoc+0x14d/0x152 ... ath0: link becomes ready ath0: deauthenticating from 00:11:95:77:e0:b0 by local choice (reason=3) ath0: no IPv6 routers present ath0: link is not ready ath0: direct probe to AP 00:11:95:77:e0:b0 (try 1) ath0: direct probe responded ath0: authenticate with AP 00:11:95:77:e0:b0 (try 1) ath0: authenticated ath0: associate with AP 00:11:95:77:e0:b0 (try 1) ath0: RX ReassocResp from 00:11:95:77:e0:b0 (capab=0x421 status=0 aid=2) ath0: associated It is not clear to me how the first "direct probe" here happens, but this seems to be a race condition, if the user requests to deauth after requesting assoc, but before the assoc response is received. In that case, it may happen that mac80211 tries to report the assoc success to cfg80211, but gets blocked on the wdev lock that is held because the user is requesting the deauth. The result is that we run into a warning. This is mostly harmless, but maybe cause an unexpected event to be sent to userspace; we'd send an assoc success event although userspace was no longer expecting that. To fix this, remove the warning and check whether the race happened and in that case abort processing. Reported-by: NJoseph Nahmias <joe@nahmias.net> Cc: stable@kernel.org Cc: 562016-quiet@bugs.debian.org Signed-off-by: NJohannes Berg <johannes@sipsolutions.net> Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>
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