All of lore.kernel.org
 help / color / mirror / Atom feed
From: Steven Rostedt <rostedt@goodmis.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-mm@kvack.org, Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@kernel.org>,
	Christoph Lameter <cl@linux.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] slub/memcg: Cure the brainless abuse of sysfs attributes
Date: Sat, 20 May 2017 10:25:50 -0400	[thread overview]
Message-ID: <20170520102550.2f793194@gandalf.local.home> (raw)
In-Reply-To: <20170520131645.GA5058@infradead.org>

On Sat, 20 May 2017 06:16:45 -0700
Christoph Hellwig <hch@infradead.org> wrote:

> On Sat, May 20, 2017 at 12:52:03PM +0200, Thomas Gleixner wrote:
> > This should be rewritten proper by adding a propagate() callback to those
> > slub_attributes which must be propagated and avoid that insane conversion
> > to and from ASCII
> 
> Exactly..
> 
> >, but that's too large for a hot fix.
> 
> What made this such a hot fix?  Looks like this crap has been in
> for quite a while.

It can cause a deadlock with get_online_cpus() that has been uncovered
by recent cpu hotplug and lockdep changes that Thomas and Peter have
been doing.

[  102.567308]  Possible unsafe locking scenario:
[  102.567308] 
[  102.574846]        CPU0                    CPU1
[  102.580148]        ----                    ----
[  102.585421]   lock(cpu_hotplug.lock);
[  102.589808]                                lock(slab_mutex);
[  102.596166]                                lock(cpu_hotplug.lock);
[  102.603028]   lock(slab_mutex);
[  102.606846] 
[  102.606846]  *** DEADLOCK ***

-- Steve

WARNING: multiple messages have this Message-ID (diff)
From: Steven Rostedt <rostedt@goodmis.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-mm@kvack.org, Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@kernel.org>,
	Christoph Lameter <cl@linux.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] slub/memcg: Cure the brainless abuse of sysfs attributes
Date: Sat, 20 May 2017 10:25:50 -0400	[thread overview]
Message-ID: <20170520102550.2f793194@gandalf.local.home> (raw)
In-Reply-To: <20170520131645.GA5058@infradead.org>

On Sat, 20 May 2017 06:16:45 -0700
Christoph Hellwig <hch@infradead.org> wrote:

> On Sat, May 20, 2017 at 12:52:03PM +0200, Thomas Gleixner wrote:
> > This should be rewritten proper by adding a propagate() callback to those
> > slub_attributes which must be propagated and avoid that insane conversion
> > to and from ASCII
> 
> Exactly..
> 
> >, but that's too large for a hot fix.
> 
> What made this such a hot fix?  Looks like this crap has been in
> for quite a while.

It can cause a deadlock with get_online_cpus() that has been uncovered
by recent cpu hotplug and lockdep changes that Thomas and Peter have
been doing.

[  102.567308]  Possible unsafe locking scenario:
[  102.567308] 
[  102.574846]        CPU0                    CPU1
[  102.580148]        ----                    ----
[  102.585421]   lock(cpu_hotplug.lock);
[  102.589808]                                lock(slab_mutex);
[  102.596166]                                lock(cpu_hotplug.lock);
[  102.603028]   lock(slab_mutex);
[  102.606846] 
[  102.606846]  *** DEADLOCK ***

-- Steve

--
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:[~2017-05-20 14:25 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-20 10:52 [PATCH] slub/memcg: Cure the brainless abuse of sysfs attributes Thomas Gleixner
2017-05-20 10:52 ` Thomas Gleixner
2017-05-20 13:16 ` Christoph Hellwig
2017-05-20 13:16   ` Christoph Hellwig
2017-05-20 14:25   ` Steven Rostedt [this message]
2017-05-20 14:25     ` Steven Rostedt
2017-05-21 20:01   ` Thomas Gleixner
2017-05-21 20:01     ` Thomas Gleixner
2017-05-22  1:25 ` David Rientjes
2017-05-22  1:25   ` David Rientjes

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=20170520102550.2f793194@gandalf.local.home \
    --to=rostedt@goodmis.org \
    --cc=akpm@linux-foundation.org \
    --cc=cl@linux.com \
    --cc=hannes@cmpxchg.org \
    --cc=hch@infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@kernel.org \
    --cc=peterz@infradead.org \
    --cc=tglx@linutronix.de \
    /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
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
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.