Re: linux-next: Tree for Dec 4
From: Dmitry Monakhov
Date: Fri Dec 05 2014 - 03:29:39 EST
Jeremiah Mahler <jmmahler@xxxxxxxxx> writes:
> On Thu, Dec 04, 2014 at 03:34:11PM -0800, Jeremiah Mahler wrote:
>> On Thu, Dec 04, 2014 at 07:59:28PM +1100, Stephen Rothwell wrote:
>> > Hi all,
>> > Changes since 20141203:
>> > --
>> > Cheers,
>> > Stephen Rothwell sfr@xxxxxxxxxxxxxxxx
>> linux-next 20141204 is broken on all my machines, 20141203 worked fine.
>> They fail very early in the boot process and are unable to mount root.
>> There are lots of "ext4_check_descriptors: Checksum for group ...
>> failed" messages.
>> Any suggestions for where to start looking?
>> - Jeremiah Mahler
> I ran a bisect and found this patch to be faulty.
> commit fdfe073987619ec375da8d8a2701ab271d1b1339
> Author: Dmitry Monakhov <dmonakhov@xxxxxxxxxx>
> Date: Tue Dec 2 16:09:16 2014 -0500
> ext4: fix potential use after free during resize
> We need some sort of synchronization while updating ->s_group_desc
> because there are a lot of users which can access old ->s_group_desc
> array after it was released.
> Signed-off-by: Dmitry Monakhov <dmonakhov@xxxxxxxxxx>
> Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
+ gd_bh = *rcu_dereference(sbi->s_group_desc) + group_desc;
Yes this is true crap. The only question is how it passed xfstess?
> - Jeremiah Mahler
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