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From: Kalle Valo <kvalo@kernel.org>
To: Alexander Wetzel <alexander@wetzel-home.de>
Cc: linux-wireless@vger.kernel.org,
	Johannes Berg <johannes@sipsolutions.net>,
	Felix Fietkau <nbd@nbd.name>,
	stable@vger.kernel.org
Subject: Re: [PATCH] mac80211: Ensure vif queues are operational after start
Date: Fri, 16 Sep 2022 08:38:31 +0300	[thread overview]
Message-ID: <87y1ujanfs.fsf@kernel.org> (raw)
In-Reply-To: <20220915130946.302803-1-alexander@wetzel-home.de> (Alexander Wetzel's message of "Thu, 15 Sep 2022 15:09:46 +0200")

Alexander Wetzel <alexander@wetzel-home.de> writes:

> Make sure local->queue_stop_reasons and vif.txqs_stopped stay in sync.
>
> When a new vif is created the queues may end up in an inconsistent state
> and be inoperable:
> Communication not using iTXQ will work, allowing to e.g. complete the
> association. But the 4-way handshake will time out. The sta will not
> send out any skbs queued in iTXQs.
>
> All normal attempts to start the queues will fail when reaching this
> state.
> local->queue_stop_reasons will have marked all queues as operational but
> vif.txqs_stopped will still be set, creating an inconsistent internal
> state.
>
> In reality this seems to be race between the mac80211 function
> ieee80211_do_open() setting SDATA_STATE_RUNNING and the wake_txqs_tasklet:
> Depending on the driver and the timing the queues may end up to be
> operational or not.
>
> Cc: stable@vger.kernel.org
> Fixes: f856373e2f31 ("wifi: mac80211: do not wake queues on a vif that is being stopped")
> Signed-off-by: Alexander Wetzel <alexander@wetzel-home.de>
> ---
>  net/mac80211/util.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

The title is missing "wifi:", but no need to resend because of this. I
assume Johannes will fix it during commit.

-- 
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

      reply	other threads:[~2022-09-16  5:38 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-15 13:09 [PATCH] mac80211: Ensure vif queues are operational after start Alexander Wetzel
2022-09-16  5:38 ` Kalle Valo [this message]

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