From: Marc Zyngier <maz@kernel.org>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
linux-kernel@vger.kernel.org,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
kernel-team@android.com
Subject: Re: [PATCH] gpio: pca953x: Survive spurious interrupts
Date: Wed, 07 Oct 2020 13:09:33 +0100 [thread overview]
Message-ID: <0175d3ce84ea0aa938a3ce9b3731762e@kernel.org> (raw)
In-Reply-To: <CAHp75Vdb3y_r_+Mq8K=Jog21wiFH54F18ED8eBwT4rM_zxcCUA@mail.gmail.com>
On 2020-10-07 13:02, Andy Shevchenko wrote:
> On Wed, Oct 7, 2020 at 12:49 PM Linus Walleij
> <linus.walleij@linaro.org> wrote:
>>
>> On Mon, Oct 5, 2020 at 4:02 PM Marc Zyngier <maz@kernel.org> wrote:
>>
>> > The pca953x driver never checks the result of irq_find_mapping(),
>> > which returns 0 when no mapping is found. When a spurious interrupt
>> > is delivered (which can happen under obscure circumstances), the
>> > kernel explodes as it still tries to handle the error code as
>> > a real interrupt.
>> >
>> > Handle this particular case and warn on spurious interrupts.
>> >
>> > Signed-off-by: Marc Zyngier <maz@kernel.org>
>
> Wait, doesn't actually [1] fix the reported issue?
Not at all.
> Marc, can you confirm this?
>
> [1]: e43c26e12dd4 ("gpio: pca953x: Fix uninitialized pending variable")
Different bug, really. If an interrupt is *really* pending, and no
mapping established yet, feeding the result of irq_find_mapping() to
handle_nested_irq() will lead to a panic.
Recently seen on a Tegra system suffering from even more pathological
bugs.
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2020-10-07 12:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-05 14:02 [PATCH] gpio: pca953x: Survive spurious interrupts Marc Zyngier
2020-10-07 9:48 ` Linus Walleij
2020-10-07 12:02 ` Andy Shevchenko
2020-10-07 12:09 ` Marc Zyngier [this message]
2020-10-07 13:10 ` Andy Shevchenko
2020-10-07 13:20 ` Marc Zyngier
2020-10-07 14:03 ` Andy Shevchenko
2020-10-07 15:00 ` Marc Zyngier
2020-10-07 15:43 ` Andy Shevchenko
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