linux-kernel - Re: [PATCH 0/2] memcg: mm_update_next

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 18 Apr 2014 20:44:41 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Michal Hocko <mhocko@...e.cz>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Peter Chiang <pchiang@...dia.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Balbir Singh <bsingharora@...il.com>,
	Johannes Weiner <hannes@...xchg.org>,
	"ccross@...roid.com" <ccross@...roid.com>,
	"lizefan@...wei.com" <lizefan@...wei.com>,
	"tj@...nel.org" <tj@...nel.org>, "pavel@....cz" <pavel@....cz>,
	"ebiederm@...ssion.com" <ebiederm@...ssion.com>,
	"guillaume@...infr.org" <guillaume@...infr.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 0/2] memcg: mm_update_next_owner() should skip kthreads

On 04/18, Michal Hocko wrote:
>
> On Fri 18-04-14 19:26:31, Oleg Nesterov wrote:
> > On 04/18, Oleg Nesterov wrote:
> > >
> > > Hmm. I seem to see a bug in this function, it can be fulled by use_mm,
> > > but I am not sure this can explain the problem. I'll send a patch.
> >
> > Untested, please review. But it really looks "obviously wrong", and note
> > that unuse_mm() doesn't do mm_update_next_owner(). (just in case, do not
> > confuse it with unuse_mm() in mm/swapfile.c).
>
> Both patches seem to be correct but I am missinng why they are marked as
> memcg: when they are touching generic mm_update_next_owner path.

Well, this is because I didn't know which prefix should I use. I looked
at git-blame to see who changed this function, picked the random 733eda7ac
"memcg: clear mm->owner when last possible owner leaves" commit and copied
"memcg" from there.

OTOH, mm->owner is used by mm/memcontrol.c, so perhaps the prefix is fine?

I do not even understand why do we have CONFIG_MM_OWNER, perhaps it should
die?

> Anyway, feel free to add
> Reviewed-by: Michal Hocko <mhocko@...e.cz>

Thanks!

Oleg.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/