linux-kernel - Re: [mmots-2016-06-09-16-49] sleeping function called from slab

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Date:	Mon, 13 Jun 2016 12:47:34 +0200
From:	Michal Hocko <mhocko@...nel.org>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
	Christoph Lameter <cl@...ux.com>,
	Vlastimil Babka <vbabka@...e.cz>,
	Stephen Rothwell <sfr@...b.auug.org.au>, linux-mm@...ck.org,
	linux-next@...r.kernel.org, linux-kernel@...r.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
	linux-kernel-owner@...r.kernel.org
Subject: Re: [mmots-2016-06-09-16-49] sleeping function called from
 slab_alloc()

On Fri 10-06-16 14:59:16, Andrew Morton wrote:
> On Fri, 10 Jun 2016 11:55:54 +0200 mhocko <mhocko@...e.de> wrote:
> 
> > On 2016-06-10 11:50, Sergey Senozhatsky wrote:
> > > Hello,
> > > 
> > > forked from http://marc.info/?l=linux-mm&m=146553910928716&w=2
> > > 
> > > new_slab()->BUG->die()->exit_signals() can be called from atomic
> > > context: local IRQs disabled in slab_alloc().
> > 
> > I have sent a patch to drop the BUG() from that path today. It
> > is just too aggressive way to react to a non-critical bug.
> > See 
> > http://lkml.kernel.org/r/1465548200-11384-2-git-send-email-mhocko@kernel.org
> 
> Doesn't this simply mean that Sergey's workload will blurt a pr_warn()
> rather than a BUG()?  That still needs fixing.  Confused.

Yes that should be fixed by
http://lkml.kernel.org/r/20160610074223.GC32285@dhcp22.suse.cz

which prevents from using a wrong GFP...

-- 
Michal Hocko
SUSE Labs