Re: [RFC]mm/zsmalloc,: trigger BUG_ON in function zs_map_object.

Sergey Senozhatsky
2017-03-29T06:43:21Z

On (03/29/17 09:20), Minchan Kim wrote:
> Hello,
>
> On Tue, Mar 28, 2017 at 03:20:22PM +0800, Yisheng Xie wrote:
> > Hi, all,
> >
> > We had backport the no-lru migration to linux-4.1, meanwhile change the
> > ZS_MAX_ZSPAGE_ORDER to 3. Then we met a BUG_ON(!page[1]).
>
> Hmm, I don't know how you backported.
>
> There isn't any problem with default ZS_MAX_ZSPAGE_ORDER. Right?
> So, it happens only if you changed it to 3?

I agree with Minchan. too much things could have gone wrong during the backport.

> Could you tell me what is your base kernel? and what zram/zsmalloc
> version(ie, from what kernel version) you backported to your
> base kernel?

agree again.

Yisheng, do you have this commit applied?

commit c102f07ca0b04f2cb49cfc161c83f6239d17f491
Author: Junil Lee <junil0814.lee@lge.com>
Date: Wed Jan 20 14:58:18 2016 -0800

zsmalloc: fix migrate_zspage-zs_free race condition

-ss