From: "Saidi, Ali" <alisaidi@amazon.com>
To: Marc Zyngier <maz@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Jason Cooper <jason@lakedaemon.net>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"Herrenschmidt, Benjamin" <benh@amazon.com>,
"Woodhouse, David" <dwmw@amazon.co.uk>,
"Zilberman, Zeev" <zeev@amazon.com>,
"Machulsky, Zorik" <zorik@amazon.com>
Subject: Re: [PATCH] irqchip/gic-v3-its: Don't try to move a disabled irq
Date: Mon, 1 Jun 2020 00:10:06 +0000 [thread overview]
Message-ID: <CBF3C648-84C9-4034-A5A0-EC110A9124E4@amazon.com> (raw)
In-Reply-To: <eed907d48de84c96e3ceb27c1ed6f622@kernel.org>
Marc,
> On May 31, 2020, at 6:10 AM, Marc Zyngier <maz@kernel.org> wrote:
>> Not great indeed. But this is not, as far as I can tell, a GIC
>> driver problem.
>>
>> The semantic of activate/deactivate (which maps to started/shutdown
>> in the IRQ code) is that the HW resources for a given interrupt are
>> only committed when the interrupt is activated. Trying to perform
>> actions involving the HW on an interrupt that isn't active cannot be
>> guaranteed to take effect.
Yes, then it absolutely makes sense to address it outside the GIC.
>>
>> I'd rather address it in the core code, by preventing set_affinity (and
>> potentially others) to take place when the interrupt is not in the
>> STARTED state. Userspace would get an error, which is perfectly
>> legitimate, and which it already has to deal with it for plenty of
>> other
>> reasons.
>
> How about this:
>
> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
> index 453a8a0f4804..1a2ac1392c0f 100644
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -147,7 +147,8 @@ cpumask_var_t irq_default_affinity;
> static bool __irq_can_set_affinity(struct irq_desc *desc)
> {
> if (!desc || !irqd_can_balance(&desc->irq_data) ||
> - !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
> + !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity ||
> + !irqd_is_started(&desc->irq_data))
> return false;
> return true;
> }
Confirmed I can’t reproduce the issue with your fix.
Thanks,
Ali
next prev parent reply other threads:[~2020-06-01 0:10 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-29 1:55 [PATCH] irqchip/gic-v3-its: Don't try to move a disabled irq Ali Saidi
2020-05-29 4:07 ` Zenghui Yu
2020-05-29 8:32 ` Marc Zyngier
2020-05-29 12:36 ` Saidi, Ali
2020-05-30 16:49 ` Marc Zyngier
2020-05-31 11:09 ` Marc Zyngier
2020-06-01 0:10 ` Saidi, Ali [this message]
2020-06-01 2:40 ` Herrenschmidt, Benjamin
2020-06-02 20:54 ` Thomas Gleixner
2020-06-03 12:44 ` Marc Zyngier
2020-05-31 2:53 ` kbuild test robot
2020-07-17 21:34 ` [tip: irq/urgent] genirq/affinity: Handle affinity setting on inactive interrupts correctly tip-bot2 for Thomas Gleixner
2020-06-02 18:47 [PATCH] irqchip/gic-v3-its: Don't try to move a disabled irq Saidi, Ali
2020-06-03 15:16 ` Marc Zyngier
2020-06-03 22:14 ` Herrenschmidt, Benjamin
2020-06-08 13:48 ` Thomas Gleixner
2020-06-08 21:59 ` Benjamin Herrenschmidt
2020-06-08 23:36 ` Thomas Gleixner
2020-06-11 17:44 Saidi, Ali
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CBF3C648-84C9-4034-A5A0-EC110A9124E4@amazon.com \
--to=alisaidi@amazon.com \
--cc=benh@amazon.com \
--cc=dwmw@amazon.co.uk \
--cc=jason@lakedaemon.net \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=maz@kernel.org \
--cc=tglx@linutronix.de \
--cc=zeev@amazon.com \
--cc=zorik@amazon.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).