From: Kalle Valo <kvalo@codeaurora.org>
To: Felix Fietkau <nbd@nbd.name>
Cc: linux-wireless@vger.kernel.org
Subject: Re: [PATCH 4/4] ath9k: fix race condition in enabling/disabling IRQs
Date: Thu, 02 Feb 2017 11:10:34 +0200 [thread overview]
Message-ID: <871svhez5h.fsf@purkki.adurom.net> (raw)
In-Reply-To: <ca32601f-81f1-aec0-9ab4-02631b226900@nbd.name> (Felix Fietkau's message of "Fri, 27 Jan 2017 13:47:06 +0100")
Felix Fietkau <nbd@nbd.name> writes:
> On 2017-01-25 17:36, Felix Fietkau wrote:
>> The code currently relies on refcounting to disable IRQs from within the
>> IRQ handler and re-enabling them again after the tasklet has run.
>>
>> However, due to race conditions sometimes the IRQ handler might be
>> called twice, or the tasklet may not run at all (if interrupted in the
>> middle of a reset).
>>
>> This can cause nasty imbalances in the irq-disable refcount which will
>> get the driver permanently stuck until the entire radio has been stopped
>> and started again (ath_reset will not recover from this).
>>
>> Instead of using this fragile logic, change the code to ensure that
>> running the irq handler during tasklet processing is safe, and leave the
>> refcount untouched.
>>
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Felix Fietkau <nbd@nbd.name>
>
> Please don't apply this yet, it looks like it might cause some
> regressions on other devices. I will investigate.
Ok, as patch 3 also had some changes I'll drop these now. So please
resend the whole patch series once you know more.
--
Kalle Valo
prev parent reply other threads:[~2017-02-02 9:10 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-25 16:36 [PATCH 1/4] ath9k: rename tx_complete_work to hw_check_work Felix Fietkau
2017-01-25 16:36 ` [PATCH 2/4] ath9k_hw: check if the chip failed to wake up Felix Fietkau
2017-01-25 16:36 ` [PATCH 3/4] ath9k: check for deaf rx path state Felix Fietkau
2017-01-26 9:50 ` Simon Wunderlich
2017-01-26 10:02 ` Felix Fietkau
2017-01-26 10:15 ` Simon Wunderlich
2017-01-26 10:26 ` Felix Fietkau
2017-01-26 10:32 ` Simon Wunderlich
2017-01-25 16:36 ` [PATCH 4/4] ath9k: fix race condition in enabling/disabling IRQs Felix Fietkau
2017-01-27 12:47 ` Felix Fietkau
2017-02-02 9:10 ` Kalle Valo [this message]
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