All of lore.kernel.org
 help / color / mirror / Atom feed
From: Lukas Wunner <lukas@wunner.de>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Marc Zyngier <maz@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Bartosz Golaszewski <brgl@bgdev.pl>,
	linux-gpio@vger.kernel.org,
	Octavian Purdila <octavian.purdila@nxp.com>,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] genirq: Deduplicate WARN_ON_ONCE() in generic_handle_domain_irq()
Date: Mon, 16 May 2022 12:04:43 +0200	[thread overview]
Message-ID: <20220516100443.GA13963@wunner.de> (raw)
In-Reply-To: <YoHvXpo8PJUDbs08@linutronix.de>

On Mon, May 16, 2022 at 08:29:50AM +0200, Sebastian Andrzej Siewior wrote:
> From looking at gpio-dln2
> this is called from USB URB's callback which is softirq. In the end
> dln2_gpio_event() is invoked while dln2_dev::event_cb_lock is acquired.
> That lock is acquired by disabling interrupts which is what gets the
> locking right for generic_handle_domain_irq(). If that lock lifted to
> spin_lock_bh() (because it is always in urb's calback context and all
> HCDs complete in one context unlike now) then this breaks.

I think you want WARN_ON(!irqs_disabled) to catch that,
not WARN_ON_ONCE(!in_hardirq()).


> and sadly I missed dln2. Please let me know if you have more users
> similar to dln2. I will add those to my list once upstream buys that
> interface.

There's another USB GPIO irqchip queued up for 5.19 now:
https://git.kernel.org/netdev/net-next/c/1ce8b37241ed

And there's one more in drivers/hid/hid-cp2112.c, but that calls
handle_nested_irq(), which disables hardirqs.

Thanks,

Lukas

      parent reply	other threads:[~2022-05-16 10:06 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-10  7:56 [PATCH] genirq: Deduplicate WARN_ON_ONCE() in generic_handle_domain_irq() Lukas Wunner
2022-05-10  7:56 ` Lukas Wunner
2022-05-16  6:29 ` Sebastian Andrzej Siewior
2022-05-16  6:29   ` Sebastian Andrzej Siewior
2022-05-16  6:53   ` Thomas Gleixner
2022-05-16  6:53     ` Thomas Gleixner
2022-05-16  7:02     ` Sebastian Andrzej Siewior
2022-05-16  7:02       ` Sebastian Andrzej Siewior
2022-05-16 10:04   ` Lukas Wunner [this message]

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=20220516100443.GA13963@wunner.de \
    --to=lukas@wunner.de \
    --cc=bigeasy@linutronix.de \
    --cc=brgl@bgdev.pl \
    --cc=kuba@kernel.org \
    --cc=linus.walleij@linaro.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-gpio@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=maz@kernel.org \
    --cc=octavian.purdila@nxp.com \
    --cc=tglx@linutronix.de \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.