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Date: Sun, 20 Feb 2011 01:15:52 -0500
From: "Ted Ts'o" <tytso@mit.edu>
To: Mark Lord <kernel@teksavvy.com>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>, linux-ext4@vger.kernel.org
Subject: Re: ext4 crash on 2.6.37: NULL ptr in ext4_discard_preallocations
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On Sun, Feb 20, 2011 at 12:05:27AM -0500, Mark Lord wrote:
> I suppose it must be, as there's no other 0x3c offset in that function.
> Which means it's probably this line that's crashing:
> 
>              BUG_ON(pa->pa_obj_lock != &ei->i_prealloc_lock);
> 
> ...which could only happen if "pa" was NULL there.
> I wonder how that happened ?

Which could only happen if ei->i_prealloc_list were not properly
initialized (i..e, it was still NULL).  Which shouldn't ever
happen...., since all ext4_inodes are initialized in
ext4_alloc_inode().

Hmm, can you replicate the crash?

					- Ted
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