From: Felix Fietkau <nbd@nbd.name>
To: "Linus Lüssing" <linus.luessing@c0d3.blue>,
"Kalle Valo" <kvalo@codeaurora.org>,
"Sujith Manoharan" <c_manoha@qca.qualcomm.com>,
ath9k-devel@qca.qualcomm.com
Cc: linux-wireless@vger.kernel.org,
"David S . Miller" <davem@davemloft.net>,
"Jakub Kicinski" <kuba@kernel.org>,
"John W . Linville" <linville@tuxdriver.com>,
"Felix Fietkau" <nbd@openwrt.org>,
"Simon Wunderlich" <sw@simonwunderlich.de>,
"Sven Eckelmann" <sven@narfation.org>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
"Linus Lüssing" <ll@simonwunderlich.de>
Subject: Re: [PATCH 3/3] ath9k: Fix potential hw interrupt resume during reset
Date: Wed, 15 Sep 2021 11:48:55 +0200 [thread overview]
Message-ID: <255a49c7-d763-50d9-87e0-da22f4a9b053@nbd.name> (raw)
In-Reply-To: <20210914192515.9273-4-linus.luessing@c0d3.blue>
On 2021-09-14 21:25, Linus Lüssing wrote:
> From: Linus Lüssing <ll@simonwunderlich.de>
>
> There is a small risk of the ath9k hw interrupts being reenabled in the
> following way:
>
> 1) ath_reset_internal()
> ...
> -> disable_irq()
> ...
> <- returns
>
> 2) ath9k_tasklet()
> ...
> -> ath9k_hw_resume_interrupts()
> ...
>
> 1) ath_reset_internal() continued:
> -> tasklet_disable(&sc->intr_tq); (= ath9k_tasklet() off)
>
> By first disabling the ath9k interrupt there is a small window
> afterwards which allows ath9k hw interrupts being reenabled through
> the ath9k_tasklet() before we disable this tasklet in
> ath_reset_internal(). Leading to having the ath9k hw interrupts enabled
> during the reset, which we should avoid.
I don't see a way in which interrupts can be re-enabled through the
tasklet. disable_irq disables the entire PCI IRQ (not through ath9k hw
registers), and they will only be re-enabled by the corresponding
enable_irq call.
- Felix
next prev parent reply other threads:[~2021-09-15 9:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-14 19:25 [PATCH 0/3] ath9k: interrupt fixes on queue reset Linus Lüssing
2021-09-14 19:25 ` [PATCH 1/3] ath9k: add option to reset the wifi chip via debugfs Linus Lüssing
2021-10-05 14:27 ` Kalle Valo
2021-09-14 19:25 ` [PATCH 2/3] ath9k: Fix potential interrupt storm on queue reset Linus Lüssing
2021-09-14 19:25 ` [PATCH 3/3] ath9k: Fix potential hw interrupt resume during reset Linus Lüssing
2021-09-15 9:48 ` Felix Fietkau [this message]
2021-09-15 19:18 ` Linus Lüssing
2021-09-14 19:53 ` [PATCH 0/3] ath9k: interrupt fixes on queue reset Toke Høiland-Jørgensen
2021-09-15 9:23 ` Linus Lüssing
2021-10-05 14:12 ` Linus Lüssing
2021-10-05 14:24 ` Kalle Valo
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