From: Richard Davies <richard@arachsys.com>
To: Michal Hocko <mhocko@suse.cz>
Cc: cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-btrfs@vger.kernel.org,
Vladimir Davydov <vdavydov@parallels.com>
Subject: Re: Kernel crash triggered by dd to file with memcg, worst on btrfs
Date: Thu, 24 Apr 2014 11:59:33 +0100 [thread overview]
Message-ID: <20140424105933.GD32011@alpha.arachsys.com> (raw)
In-Reply-To: <20140423215852.GA6651@dhcp22.suse.cz>
Michal Hocko wrote:
> Richard Davies wrote:
> > I have a test case in which I can often crash an entire machine by running
> > dd to a file with a memcg with relatively generous limits. This is
> > simplified from real world problems with heavy disk i/o inside containers.
...
> > [I have also just reported a different but similar bug with untar in a memcg
> > http://marc.info/?l=linux-mm&m=139766321822891 That one is not btrfs-linked]
...
> Does this happen even if no kmem limit is specified?
No, it only happens with a kmem limit.
So it is due to the kmem limiting being broken, as we discussed in the other
"untar" thread lined above.
> The kmem limit would explain allocation failures for ext3 logged below
> but I would be interested about the "Thread overran stack, or stack
> corrupted" message reported for btrfs. The stack doesn't seem very deep
> there. I would expect some issues in the writeback path during the limit
> reclaim but this looks quite innocent. Rulling out kmem accounting would
> be a good first step though . (I am keepinng the full email for Vladimir)
The btrfs problems only occur with a kmem limit. So this is also kmem-linked
even if that is surprising.
Richard.
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next prev parent reply other threads:[~2014-04-24 10:59 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-16 17:42 Richard Davies
2014-04-16 17:58 ` Marian Marinov
2014-04-16 18:05 ` Richard Davies
2014-04-16 17:58 ` Richard Davies
2014-04-23 21:58 ` Michal Hocko
2014-04-24 10:59 ` Richard Davies [this message]
2014-04-24 12:26 ` Michal Hocko
2014-04-24 12:19 ` Vladimir Davydov
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