* Re: vfs-scale-working: NULL dereference in vfat_cmpi()
[not found] <AANLkTimCNB-PEF6CbW1WrM4KJMALvS0v+G6zkYqrnbOK@mail.gmail.com>
@ 2010-12-03 17:27 ` Nick Piggin
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From: Nick Piggin @ 2010-12-03 17:27 UTC (permalink / raw)
To: sedat.dilek; +Cc: Nick Piggin, linux-fsdevel
On Wed, Dec 01, 2010 at 05:32:39PM +0100, Sedat Dilek wrote:
> Hi Nick,
>
> while playing with the vfs-scale-working I discovered besides the
> problem in [1] also a NULL dereference in vfat_cmpi() (see attached
> screenshot).
>
> This happened when I wanted to copy pics stored on a 256M SDcard
> (plugged into a Transcend USB2-SDcard-adapter for faster reading data)
> to my local harddisk.
>
> The system was frozen - again a brutal cold start.
>
> Hope this helps you finding the bug.
Ah it does, thanks. It tried to dereference NULL inode from negative
dentry. First line of vat_cmpi should be parent->d_sb rather than
inode->i_sb.
I think I'll want to tweak the d_compare API change not to pass the
inode in, to avoid this possibility.
Thanks,
Nick
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