From: Andrew Lunn <andrew@lunn.ch>
To: John David Anglin <dave.anglin@bell.net>
Cc: Russell King <linux@arm.linux.org.uk>,
Vivien Didelot <vivien.didelot@savoirfairelinux.com>,
Florian Fainelli <f.fainelli@gmail.com>,
netdev@vger.kernel.org
Subject: Re: [PATCH v2] net: dsa: mv88e6xxx: Revise irq setup ordering
Date: Tue, 5 Feb 2019 00:14:10 +0100 [thread overview]
Message-ID: <20190204231410.GG3397@lunn.ch> (raw)
In-Reply-To: <824d011b-3692-69c3-5e2c-58e950a80abf@bell.net>
On Mon, Feb 04, 2019 at 04:59:13PM -0500, John David Anglin wrote:
> This change fixes a race condition in the setup of hardware irqs and the
> code enabling PHY link detection in the mv88e6xxx driver.
>
> This race was observed on the espressobin board where the GPIO interrupt
> controller only supports edge interrupts. If the INTn output pin goes low
> before the GPIO interrupt is enabled, PHY link interrupts are not detected.
>
> With this change, we
> 1) force INTn high by clearing all interrupt enables in global 1 control 1,
> 2) setup the hardware irq, and then
> 3) perform the remaining common setup.
>
> This simplifies the setup and allows some unnecessary code to be removed.
Hi Dave
I took a closer look now. I don't actually see why the current code is
wrong.
mv88e6xxx_g1_irq_setup() calls mv88e6xxx_g1_irq_setup_common() and
then registers the interrupt handler.
mv88e6xxx_g1_irq_setup_common() does what you want, it masks all
interrupts in the hardware and clears any pending interrupts which can
be cleared.
The change you made is actually dangerous. As soon as you request the
interrupt, it is live, it can fire, and call
mv88e6xxx_g1_irq_thread_work(). That needs the irq domain. But the
change you made defers the creating of the domain until after the
interrupt is registered. So we can de-refernece a NULL pointer in the
interrupt handler.
Andrew
next prev parent reply other threads:[~2019-02-04 23:14 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-22 19:16 net: phylink: dsa: mv88e6xxx: flaky link detection on switch ports with internal PHYs John David Anglin
2019-01-22 20:28 ` Andrew Lunn
2019-01-22 21:40 ` John David Anglin
2019-01-22 22:36 ` Andrew Lunn
2019-01-22 23:52 ` John David Anglin
2019-01-23 0:11 ` John David Anglin
2019-01-23 0:22 ` Andrew Lunn
2019-01-25 16:30 ` John David Anglin
2019-01-25 16:48 ` Russell King - ARM Linux admin
2019-01-25 18:38 ` John David Anglin
2019-01-30 17:08 ` John David Anglin
2019-01-30 17:28 ` Andrew Lunn
2019-01-30 19:01 ` John David Anglin
2019-01-30 19:09 ` Andrew Lunn
2019-01-30 22:24 ` John David Anglin
2019-01-30 22:38 ` Andrew Lunn
2019-01-31 1:27 ` John David Anglin
2019-01-31 17:27 ` John David Anglin
2019-02-04 18:37 ` [PATCH] net: phylink: dsa: mv88e6xxx: Revise irq setup ordering John David Anglin
2019-02-04 19:35 ` Andrew Lunn
2019-02-04 19:52 ` John David Anglin
2019-02-04 20:19 ` Andrew Lunn
2019-02-04 21:38 ` John David Anglin
2019-02-04 22:47 ` Andrew Lunn
2019-02-04 21:59 ` [PATCH v2] net: " John David Anglin
2019-02-04 23:14 ` Andrew Lunn [this message]
2019-02-05 0:38 ` John David Anglin
2019-02-05 2:21 ` Andrew Lunn
2019-02-05 19:20 ` John David Anglin
2019-02-05 19:54 ` Andrew Lunn
2019-02-05 18:37 ` David Miller
2019-02-11 18:40 ` [PATCH net] dsa: mv88e6xxx: Ensure all pending interrupts are handled prior to exit John David Anglin
2019-02-11 23:33 ` Andrew Lunn
2019-02-12 0:57 ` John David Anglin
2019-02-12 1:21 ` Andrew Lunn
2019-02-12 3:58 ` Andrew Lunn
2019-02-12 6:51 ` Heiner Kallweit
2019-02-12 12:56 ` Andrew Lunn
2019-02-12 18:42 ` Heiner Kallweit
2019-02-12 20:09 ` John David Anglin
2019-02-12 16:30 ` Russell King - ARM Linux admin
2019-02-12 20:11 ` Heiner Kallweit
2019-02-12 20:54 ` Heiner Kallweit
2019-02-12 22:55 ` Russell King - ARM Linux admin
2019-02-14 2:07 ` Andrew Lunn
2019-02-14 4:47 ` David Miller
2019-02-14 4:50 ` Andrew Lunn
2019-02-14 15:27 ` David Miller
2019-01-22 23:12 ` net: phylink: dsa: mv88e6xxx: flaky link detection on switch ports with internal PHYs Andrew Lunn
2019-01-22 23:48 ` John David Anglin
2019-01-23 0:00 ` John David Anglin
2019-01-23 0:04 ` Florian Fainelli
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