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In-Reply-To: <1429708841-31189-1-git-send-email-semen.protsenko@globallogic.com>
References: <1429708841-31189-1-git-send-email-semen.protsenko@globallogic.com>
Date: Wed, 6 May 2015 15:09:45 +0200
Message-ID: <CACRpkdZqftDFEaXTFYV=9hmoCmDH+FDmNHdMN9_Se9dgiuc7xQ@mail.gmail.com>
Subject: Re: [PATCH v2] gpio: max732x: Fix irq-events handler
From: Linus Walleij <linus.walleij@linaro.org>
To: Semen Protsenko <semen.protsenko@globallogic.com>
Cc: Alexandre Courbot <gnurou@gmail.com>,
        "linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Grygorii Strashko <grygorii.strashko@globallogic.com>
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On Wed, Apr 22, 2015 at 3:20 PM, Semen Protsenko
<semen.protsenko@globallogic.com> wrote:

> MAX732X clears all pending interrupts on I2C read (when interrupts
> register is being read). Driver doesn't need to send any ACKs when
> interrupt was handled. So replace handle_edge_irq() with
> handle_simple_irq().
>
> Using handle_edge_irq() (w/o .irq_ack callback set) may lead to NULL
> pointer dereference in some cases. E.g. this was observed on
> hibernation process:
>
>   Unable to handle kernel NULL pointer dereference at virtual address 0
>   Backtrace:
>   (handle_edge_irq) from (resend_irqs)
>   (resend_irqs) from (tasklet_action)
>   (tasklet_action) from (__do_softirq)
>   (__do_softirq) from (run_ksoftirqd)
>   (run_ksoftirqd) from (smpboot_thread_fn)
>   (smpboot_thread_fn) from (kthread)
>   (kthread) from (ret_from_fork)
>
> Signed-off-by: Semen Protsenko <semen.protsenko@globallogic.com>

Patch applied with Grygorii's Review tag.

Yours,
Linus Walleij
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