linux-kernel - Re: [PATCH 3/6] cgroup: introduce cgroup_taskset and use it in subsys->can_attach(), cancel

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:	Thu, 25 Aug 2011 17:21:40 +0900
From:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To:	Tejun Heo <tj@...nel.org>
Cc:	rjw@...k.pl, paul@...lmenage.org, lizf@...fujitsu.com,
	linux-pm@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
	containers@...ts.linux-foundation.org,
	Balbir Singh <bsingharora@...il.com>,
	Daisuke Nishimura <nishimura@....nes.nec.co.jp>,
	James Morris <jmorris@...ei.org>
Subject: Re: [PATCH 3/6] cgroup: introduce cgroup_taskset and use it in
 subsys->can_attach(), cancel_attach() and attach()

On Thu, 25 Aug 2011 10:20:49 +0200
Tejun Heo <tj@...nel.org> wrote:

> Hello, KAMEZAWA.
> 

> > > @@ -5460,8 +5460,9 @@ static void mem_cgroup_clear_mc(void)
> > >  
> > >  static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
> > >  				struct cgroup *cgroup,
> > > -				struct task_struct *p)
> > > +				struct cgroup_taskset *tset)
> > >  {
> > > +	struct task_struct *p = cgroup_taskset_first(tset);
> > >  	int ret = 0;
> > >  	struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup);
> > >  
> > 
> > Ah..hmm. I think this doesn't work as expected for memcg.
> > Maybe code like this will be required.
> 
> Hmmm... the above is basically identity transformation of the existing
> code.  If the above is broken, the current code is broken too.  Is it?
> 
Current code is not broken.

mem_cgroup_can_attach(....., task) need to do real job only when task->mm->owner
== task. In this modification, you pass a set of task at once.
So, mem_cgroup_can_attach() need to check _all_ tasks in tset rather than a
first task in tset. please scan and find mm->owner.

Anyway, if you merge this onto mm-tree first, I think I can have time to
write a fix up if complicated.

Thanks,
-Kame

--
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/