Date: Thu, 15 Jan 2009 07:05:21 +0100
From: Pierre Ossman <drzeus@drzeus.cx>
To: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: sdhci-devel@list.drzeus.cx, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sdhci: Fix potential spinlock recursion
Message-ID: <20090115070521.25c3bda7@mjolnir.drzeus.cx>
In-Reply-To: <20090114194159.GA25017@oksana.dev.rtsoft.ru>
References: <20090114194159.GA25017@oksana.dev.rtsoft.ru>
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On Wed, 14 Jan 2009 22:41:59 +0300
Anton Vorontsov <avorontsov@ru.mvista.com> wrote:

>=20
> This happens because plain spin_lock() won't protect us from
> softirqs (tasklets). So in the sdhci interrupt handler we must
> grab the _irq version of the lock.
>=20

?! The docs I've read state that softirq:s are not executed until all
the hardirq:s have finished processing. And looking at your code, that
seems to still hold true. A softirq running esdhc_tasklet_card() gets
preempted by a hard irq and we have the lockup.

If you're running the code you sent a few minutes later, then something
is broken with your platform as esdhc_tasklet_card() clearly tries to
disable interrupts when it grabs the lock.

Rgds
--=20
     -- Pierre Ossman

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