From: Kalle Valo <kvalo@kernel.org>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: "Johannes Berg" <johannes@sipsolutions.net>,
"Toke Høiland-Jørgensen" <toke@kernel.org>,
"Felix Fietkau" <nbd@nbd.name>,
linux-wireless@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH v2] wifi: mac80211: do not abuse fq.lock in ieee80211_do_stop()
Date: Tue, 26 Jul 2022 17:38:18 +0300 [thread overview]
Message-ID: <87o7xcq6qt.fsf@kernel.org> (raw)
In-Reply-To: <9487e319-7ab4-995a-ddfd-67c4c701680c@I-love.SAKURA.ne.jp> (Tetsuo Handa's message of "Tue, 26 Jul 2022 15:55:35 +0900")
(please don't top post, I manually fixed that)
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> writes:
> On 2022/07/18 21:01, Kalle Valo wrote:
>> Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> wrote:
>>
>>> lockdep complains use of uninitialized spinlock at ieee80211_do_stop() [1],
>>> for commit f856373e2f31ffd3 ("wifi: mac80211: do not wake queues on a vif
>>> that is being stopped") guards clear_bit() using fq.lock even before
>>> fq_init() from ieee80211_txq_setup_flows() initializes this spinlock.
>>>
>>> According to discussion [2], Toke was not happy with expanding usage of
>>> fq.lock. Since __ieee80211_wake_txqs() is called under RCU read lock, we
>>> can instead use synchronize_rcu() for flushing ieee80211_wake_txqs().
>>>
>>> Link: https://syzkaller.appspot.com/bug?extid=eceab52db7c4b961e9d6 [1]
>>> Link: https://lkml.kernel.org/r/874k0zowh2.fsf@toke.dk [2]
>>> Reported-by: syzbot <syzbot+eceab52db7c4b961e9d6@syzkaller.appspotmail.com>
>>> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
>>> Fixes: f856373e2f31ffd3 ("wifi: mac80211: do not wake queues on a vif that is being stopped")
>>> Tested-by: syzbot <syzbot+eceab52db7c4b961e9d6@syzkaller.appspotmail.com>
>>> Acked-by: Toke Høiland-Jørgensen <toke@kernel.org>
>>
>> Patch applied to wireless-next.git, thanks.
>>
>> 3598cb6e1862 wifi: mac80211: do not abuse fq.lock in ieee80211_do_stop()
>
> Since this patch fixes a regression introduced in 5.19-rc7, can this patch go to 5.19-final ?
>
> syzbot is failing to test linux.git for 12 days due to this regression.
> syzbot will fail to bisect new bugs found in the upcoming merge window
> if unable to test v5.19 due to this regression.
I took this to wireless-next as I didn't think there's enough time to
get this to v5.19 (and I only heard Linus' -rc8 plans after the fact).
So this will be in v5.20-rc1 and I recommend pushing this to a v5.19
stable release.
--
https://patchwork.kernel.org/project/linux-wireless/list/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
next prev parent reply other threads:[~2022-07-26 14:38 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-14 12:08 [syzbot] INFO: trying to register non-static key in ieee80211_do_stop syzbot
2022-07-17 2:32 ` [PATCH] wifi: mac80211: initialize fq.lock as early as possible Tetsuo Handa
2022-07-17 12:21 ` [PATCH v2] wifi: mac80211: do not abuse fq.lock in ieee80211_do_stop() Tetsuo Handa
2022-07-18 11:22 ` Toke Høiland-Jørgensen
2022-07-18 12:01 ` Kalle Valo
2022-07-26 6:55 ` Tetsuo Handa
2022-07-26 14:38 ` Kalle Valo [this message]
2022-07-26 15:05 ` Ben Greear
2022-07-26 21:38 ` Jakub Kicinski
2022-07-28 23:00 ` Tetsuo Handa
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