All of lore.kernel.org
 help / color / mirror / Atom feed
From: Marc Zyngier <marc.zyngier@arm.com>
To: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Woojung Huh <woojung.huh@microchip.com>,
	Eric Anholt <eric@anholt.net>,
	Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>,
	<netdev@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>
Subject: Re: lan78xx: WARNING: irq 79 handler enabled interrupts
Date: Sat, 29 Dec 2018 09:41:38 +0000	[thread overview]
Message-ID: <86efa0brfx.wl-marc.zyngier@arm.com> (raw)
In-Reply-To: <1082628525.187562.1546041777025@email.ionos.de>

On Sat, 29 Dec 2018 00:02:57 +0000,
Stefan Wahren <stefan.wahren@i2se.com> wrote:

Hi Stephan,

> 
> Hi,
> while booting my Raspberry Pi 3 B+ with Linux 4.20 (arm64/defconfig)
> i'm getting the following warning:
> 
> [   11.005738] irq 79 handler irq_default_primary_handler+0x0/0x8 enabled interrupts

[...]

> This seems to come from the lan78xx driver, because i don't get this
> warning on the RPI 3B (smsc95xx).
> 
> What's the approach to fix this issue?  Is it just simply replace
> spin_lock_irq() with spin_lock_irqsave() at the right places?

No, this is more pathological than that. The USB framework seems to be
using threaded interrupts, which implies that interrupts are
re-enabled as soon as it has run.

In turn, this driver is using handle_simple_irq() as its flow, which
definitely expect interrupts to be disabled.

I have no insight in how this driver works, but I'm happy to help if
someone explains the interrupt flow of this thing.

	M.

-- 
Jazz is not dead, it just smell funny.

WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <marc.zyngier@arm.com>
To: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Woojung Huh <woojung.huh@microchip.com>,
	Eric Anholt <eric@anholt.net>,
	netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>
Subject: Re: lan78xx: WARNING: irq 79 handler enabled interrupts
Date: Sat, 29 Dec 2018 09:41:38 +0000	[thread overview]
Message-ID: <86efa0brfx.wl-marc.zyngier@arm.com> (raw)
In-Reply-To: <1082628525.187562.1546041777025@email.ionos.de>

On Sat, 29 Dec 2018 00:02:57 +0000,
Stefan Wahren <stefan.wahren@i2se.com> wrote:

Hi Stephan,

> 
> Hi,
> while booting my Raspberry Pi 3 B+ with Linux 4.20 (arm64/defconfig)
> i'm getting the following warning:
> 
> [   11.005738] irq 79 handler irq_default_primary_handler+0x0/0x8 enabled interrupts

[...]

> This seems to come from the lan78xx driver, because i don't get this
> warning on the RPI 3B (smsc95xx).
> 
> What's the approach to fix this issue?  Is it just simply replace
> spin_lock_irq() with spin_lock_irqsave() at the right places?

No, this is more pathological than that. The USB framework seems to be
using threaded interrupts, which implies that interrupts are
re-enabled as soon as it has run.

In turn, this driver is using handle_simple_irq() as its flow, which
definitely expect interrupts to be disabled.

I have no insight in how this driver works, but I'm happy to help if
someone explains the interrupt flow of this thing.

	M.

-- 
Jazz is not dead, it just smell funny.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2018-12-29  9:41 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-29  0:02 lan78xx: WARNING: irq 79 handler enabled interrupts Stefan Wahren
2018-12-29  0:02 ` Stefan Wahren
2018-12-29  9:41 ` Marc Zyngier [this message]
2018-12-29  9:41   ` Marc Zyngier
2018-12-30  3:25   ` Woojung.Huh
2018-12-30  3:25     ` Woojung.Huh
2019-01-01 21:31     ` Stefan Wahren
2019-01-01 21:31       ` Stefan Wahren
2019-01-02 21:42       ` Woojung.Huh
2019-01-02 21:42         ` Woojung.Huh
2019-02-05 19:57       ` Stefan Wahren
2019-02-05 19:57         ` Stefan Wahren

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=86efa0brfx.wl-marc.zyngier@arm.com \
    --to=marc.zyngier@arm.com \
    --cc=UNGLinuxDriver@microchip.com \
    --cc=eric@anholt.net \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=netdev@vger.kernel.org \
    --cc=stefan.wahren@i2se.com \
    --cc=woojung.huh@microchip.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 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.