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From:   Chengfeng Ye <dg573847474@gmail.com>
Date:   Wed, 5 Jul 2023 00:18:00 +0800
Message-ID: <CAAo+4rV1gFhCpS0=bQa-nBmDLrQ2tensXii5GDfEkTb=9SvbhA@mail.gmail.com>
Subject: Re: [PATCH] watchdog: s3c2410: Fix potential deadlock on &wdt->lock
To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc:     alim.akhtar@samsung.com, wim@linux-watchdog.org,
        linux@roeck-us.net, linux-arm-kernel@lists.infradead.org,
        linux-samsung-soc@vger.kernel.org, linux-watchdog@vger.kernel.org,
        linux-kernel@vger.kernel.org
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Please kindly note that I am resending the last email since it did not
reach maillist.

> Hi, Krzysztof
> Thanks for the reply.
> > This interrupt is a threaded interrupt. Therefore the
> > s3c2410wdt_keepalive() will be called again from process thread. Are you
> > sure there is deadlock?
> Is it really that s3c2410wdt_irq is a threaded interrupt? I could be wrong but I can
> see that the interrupt is registered via the following code. It is the third argument
> of devm_request_irq but not devm_request_threaded_irq or request_threaded_irq,
> as far as I know, it should be an interrupt handler for the interrupt line wdt_irq
> executed under irq context.
> ret = devm_request_irq(dev, wdt_irq, s3c2410wdt_irq, 0, pdev->name, pdev);
> > Anyway, please also strip unrelated paths and rather use function names,
> > not references to lines, because these might be not accurate.
> No problem, I will provide a new patch with the function name soon.
> Best Regards,
> Chengfeng