[dm-devel] Re: 2.6.24 Kernel Soft Lock Up with heavy I/O in dm-crypt

[Milan Broz]

Yan Li wrote:
> On Thu, 28 Feb 2008 23:20:48 -0800, Andrew Morton wrote:
>> On Thu, 28 Feb 2008 19:24:03 +0530 Ritesh Raj Sarraf <rrs at researchut.com> wrote:
>>> I noted kernel soft lockup messages on my laptop when doing a lot of I/O 
>>> (200GB) to a dm-crypt device. It was setup using LUKS.
>>> The I/O never got disrupted nor anything failed. Just the messages.
> 
> I met the same problem yesterday.
> 
>> Could be a dm-crypt problem, could be a crypto problem, could even be a
>> core block problems.
> 
> I think it's due to heavy encryption computation that run longer than
> 10s and triggered the warning. By heavy I mean dm-crypt with
> aes-xts-plain, 512b key size.
> 
> This is a typical soft lockup call trace snip from dmesg:
> Call Trace:
>  [<ffffffff882c60b6>] :xts:crypt+0x9d/0xea
>  [<ffffffff882b5705>] :aes_x86_64:aes_encrypt+0x0/0x5
>  [<ffffffff882b5705>] :aes_x86_64:aes_encrypt+0x0/0x5
>  [<ffffffff882c622e>] :xts:encrypt+0x41/0x46
>  [<ffffffff8828273f>] :dm_crypt:crypt_convert_scatterlist+0x7b/0xc7
>  [<ffffffff882828ae>] :dm_crypt:crypt_convert+0x123/0x15d
>  [<ffffffff88282abd>] :dm_crypt:kcryptd_do_crypt+0x1d5/0x253
>  [<ffffffff882828e8>] :dm_crypt:kcryptd_do_crypt+0x0/0x253
>  [<ffffffff802448e5>] run_workqueue+0x7f/0x10b
> ... (omitted)

Please could you try if  patch here helps and doesn't cause performance degradation?

http://www2.kernel.org/pub/linux/kernel/people/agk/patches/2.6/2.6.25/dm-crypt-add-cond_resched.patch

...
> Anybody see a data corruption?

It shouldn't cause any corruption of data.

Milan