All of lore.kernel.org
 help / color / mirror / Atom feed
From: Tejun Heo <tj@kernel.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Vladimir Davydov <vdavydov@virtuozzo.com>,
	cgroups@vger.kernel.org, linux-mm@kvack.org, kernel-team@fb.com
Subject: Re: [PATCH] memcg: add RCU locking around css_for_each_descendant_pre() in memcg_offline_kmem()
Date: Fri, 27 May 2016 11:51:40 -0400	[thread overview]
Message-ID: <20160527155140.GN23194@mtj.duckdns.org> (raw)
In-Reply-To: <20160527153124.GT27686@dhcp22.suse.cz>

On Fri, May 27, 2016 at 05:31:24PM +0200, Michal Hocko wrote:
> On Thu 26-05-16 14:02:02, Andrew Morton wrote:
> > On Thu, 26 May 2016 16:30:18 -0400 Tejun Heo <tj@kernel.org> wrote:
> > 
> > > memcg_offline_kmem() may be called from memcg_free_kmem() after a css
> > > init failure.  memcg_free_kmem() is a ->css_free callback which is
> > > called without cgroup_mutex and memcg_offline_kmem() ends up using
> > > css_for_each_descendant_pre() without any locking.  Fix it by adding
> > > rcu read locking around it.
> > > 
> > >  mkdir: cannot create directory ___65530___: No space left on device
> > >  [  527.241361] ===============================
> > >  [  527.241845] [ INFO: suspicious RCU usage. ]
> > >  [  527.242367] 4.6.0-work+ #321 Not tainted
> > >  [  527.242730] -------------------------------
> > >  [  527.243220] kernel/cgroup.c:4008 cgroup_mutex or RCU read lock required!
> > 
> > cc:stable?
> 
> Also which kernel versions would be affected? I have tried to look and
> got lost in the indirection of the css_free path.

I think it's actually from 0b8f73e10428 ("mm: memcontrol: clean up
alloc, online, offline, free functions") which got merged during this
cycle, so no need for -stable.

Thanks.

-- 
tejun

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

  reply	other threads:[~2016-05-27 15:51 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-26 20:30 Tejun Heo
2016-05-26 21:02 ` Andrew Morton
2016-05-27 15:31   ` Michal Hocko
2016-05-27 15:51     ` Tejun Heo [this message]
2016-05-31  9:33       ` Michal Hocko
2016-05-27  8:17 ` Vladimir Davydov
2016-05-27 17:19 ` Johannes Weiner

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20160527155140.GN23194@mtj.duckdns.org \
    --to=tj@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=cgroups@vger.kernel.org \
    --cc=hannes@cmpxchg.org \
    --cc=kernel-team@fb.com \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@kernel.org \
    --cc=vdavydov@virtuozzo.com \
    --subject='Re: [PATCH] memcg: add RCU locking around css_for_each_descendant_pre() in memcg_offline_kmem()' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.