linux-kernel - RE: [Bug 25832] kernel crashes when a mounted ext3/4 file system is physically removed

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Message-ID: <Pine.LNX.4.44L0.1109231114460.2059-100000@iolanthe.rowland.org>
Date:	Fri, 23 Sep 2011 11:18:41 -0400 (EDT)
From:	Alan Stern <stern@...land.harvard.edu>
To:	Rocko Requin <rockorequin@...mail.com>
cc:	hare@...e.de, <j-nomura@...jp.nec.com>, <ben@...adent.org.uk>,
	<jaxboe@...ionio.com>, <james.bottomley@...senpartnership.com>,
	<tytso@....edu>, <linux-kernel@...r.kernel.org>,
	<linux-scsi@...r.kernel.org>
Subject: RE: [Bug 25832] kernel crashes when a mounted ext3/4 file system is
 physically removed

On Thu, 22 Sep 2011, Rocko Requin wrote:

> > Rocko:
> > 
> > Can you try testing this patch instead of all the patches I sent to 
> > you (but keep Ted's patch)?
> > 
> > Alan Stern
> > 
> 
> The simpler patch (in conjunction with Ted's patch) does stop the
> crashes. I get the same results as before: no kernel crashes
> (marvellous!), but the script's attempt to umount fails. I can then
> manually umount afterwards.

That sounds like a problem in the ext4 unmount implementation.  Ted
should be able to help track it down.

What happens if you change your script to try two unmounts in a row?  
In theory, the second should work like your manual unmount.

> Are these patches likely to be backported to the 3.0 kernel?

Yes, I should think so.  The ext4/ext3 patches may be ported even
farther back.

Alan Stern

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