From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mark Lord <liml@rtr.ca>
Subject: Hard lockup with ata_piix 2.6.21.1: strange traceback, too
Date: Wed, 20 Jun 2007 17:12:13 -0400
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To: Tejun Heo <htejun@gmail.com>, Jeff Garzik <jgarzik@pobox.com>, Alan Cox <alan@redhat.com>, IDE/ATA development list <linux-ide@vger.kernel.org>

Hi guys,

I'm debugging a system here based on ICH7/ata_piix.
When we hot-pull a drive, it locks up solid.
That's fine, but I'd like to find/fix the lockup.

So as part of poking around, I rebuilt the kernel with frame pointers,
and inserted a WARN_ON(1) into ata_busy_sleep() to see who was calling it
just before things locked up. 

Here's the result:  http://rtr.ca/libata.png

Can anyone here make sense of that traceback??
Are we *really* recursing inside the EH code?

Thanks