From: Kalle Valo <kvalo@codeaurora.org>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: Sumit Garg <sumit.garg@linaro.org>,
linux-wireless@vger.kernel.org, davem@davemloft.net,
kuba@kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, matthias.schoepfer@ithinx.io,
Philipp.Berg@liebherr.com, Michael.Weitner@liebherr.com,
daniel.thompson@linaro.org, loic.poulain@linaro.org,
stable@vger.kernel.org
Subject: Re: [PATCH] mac80211: fix race in ieee80211_register_hw()
Date: Mon, 06 Apr 2020 15:52:59 +0300 [thread overview]
Message-ID: <87r1x0zsgk.fsf@kamboji.qca.qualcomm.com> (raw)
In-Reply-To: <1e352e2130e19aec5aa5fc42db397ad50bb4ad05.camel@sipsolutions.net> (Johannes Berg's message of "Mon, 06 Apr 2020 14:47:43 +0200")
Johannes Berg <johannes@sipsolutions.net> writes:
> On Mon, 2020-04-06 at 15:44 +0300, Kalle Valo wrote:
>>
>> > user-space ieee80211_register_hw() RX IRQ
>> > +++++++++++++++++++++++++++++++++++++++++++++
>> > | | |
>> > |<---wlan0---wiphy_register() |
>> > |----start wlan0---->| |
>> > | |<---IRQ---(RX packet)
>> > | Kernel crash |
>> > | due to unallocated |
>> > | workqueue. |
>
> [snip]
>
>> I have understood that no frames should be received until mac80211 calls
>> struct ieee80211_ops::start:
>>
>> * @start: Called before the first netdevice attached to the hardware
>> * is enabled. This should turn on the hardware and must turn on
>> * frame reception (for possibly enabled monitor interfaces.)
>
> True, but I think he's saying that you can actually add and configure an
> interface as soon as the wiphy is registered?
With '<---IRQ---(RX packet)' I assumed wcn36xx is delivering a frame to
mac80211 using ieee80211_rx(), but of course I'm just guessing here.
--
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
next prev parent reply other threads:[~2020-04-06 12:53 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-06 12:21 [PATCH] mac80211: fix race in ieee80211_register_hw() Sumit Garg
2020-04-06 12:44 ` Johannes Berg
2020-04-06 13:00 ` Sumit Garg
2020-04-06 12:44 ` Kalle Valo
2020-04-06 12:47 ` Johannes Berg
2020-04-06 12:52 ` Kalle Valo [this message]
2020-04-06 12:53 ` Johannes Berg
2020-04-06 13:04 ` Kalle Valo
2020-04-06 13:07 ` Johannes Berg
2020-04-06 13:21 ` Sumit Garg
2020-04-06 13:27 ` Kalle Valo
2020-04-06 13:55 ` Krishna Chaitanya
2020-04-06 14:01 ` Johannes Berg
2020-04-06 14:25 ` Krishna Chaitanya
2020-04-06 15:06 ` Johannes Berg
2020-04-06 18:08 ` Krishna Chaitanya
2020-04-07 6:42 ` Sumit Garg
2020-04-06 13:06 ` Sumit Garg
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