[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <87zfx98r6a.fsf_-_@kernel.org>
Date: Sat, 13 Jan 2024 12:26:53 +0200
From: Kalle Valo <kvalo@...nel.org>
To: Johan Hovold <johan@...nel.org>
Cc: Johan Hovold <johan+linaro@...nel.org>, Jeff Johnson
<quic_jjohnson@...cinc.com>, ath11k@...ts.infradead.org,
linux-wireless@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: ath11k: checking RCU usage
(old discussion, changing title)
Johan Hovold <johan@...nel.org> writes:
> On Tue, Oct 24, 2023 at 05:07:38PM +0300, Kalle Valo wrote:
>
>> Johan Hovold <johan+linaro@...nel.org> writes:
>>
>> > RCU lockdep reported suspicious RCU usage when accessing the temperature
>> > sensor. Inspection revealed that the DFS radar event code was also
>> > missing the required RCU read-side critical section marking.
>> >
>> > Johan
>> >
>> >
>> > Changes in v2
>> > - add the missing rcu_read_unlock() to an
>> > ath11k_wmi_pdev_temperature_event() error path as noticed by Jeff
>> >
>> >
>> > Johan Hovold (2):
>> > wifi: ath11k: fix temperature event locking
>> > wifi: ath11k: fix dfs radar event locking
>>
>> Thanks for the fixes. I really like using lockdep_assert_held() to
>> document if a function requires some lock held, is there anything
>> similar for RCU?
>
> Not really, but the checking is instead built into the primitives like
> rcu_dereference() and enabled whenever CONFIG_PROVE_RCU is set.
>
> For some special cases, we have open-coded checks like:
>
> RCU_LOCKDEP_WARN(!rcu_read_lock_held());
>
> which similarly depend on CONFIG_PROVE_RCU or simply
>
> WARN_ON_ONCE(!rcu_read_lock_held());
I just found out that sparse has __must_hold():
https://lore.kernel.org/linux-wireless/87sf31hhfp.fsf@kernel.org/
That looks promising, should we start using that in ath11k and ath12k to
check our RCU usage?
--
https://patchwork.kernel.org/project/linux-wireless/list/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
Powered by blists - more mailing lists