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From: Dave Jones <davej@redhat.com>
To: David Rientjes <rientjes@google.com>,
	Tang Chen <tangchen@cn.fujitsu.com>,
	tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com,
	akpm@linux-foundation.org, zhangyanfei@cn.fujitsu.com,
	guz.fnst@cn.fujitsu.com, x86@kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] numa, mem-hotplug: Fix stack overflow in numa when seting kernel nodes to unhotpluggable.
Date: Thu, 23 Jan 2014 17:31:36 -0500	[thread overview]
Message-ID: <20140123223136.GA18468@redhat.com> (raw)
In-Reply-To: <20140123065824.GA17684@redhat.com>

On Thu, Jan 23, 2014 at 01:58:24AM -0500, Dave Jones wrote:

 > 128 bytes is a pretty small amount of stack though, so I'm just as confused
 > as to what the actual bug here is.
 > 
 > After trying the proposed fix, I got another oops in the early init code..
 > 
 > <trace>
 > nr_free_zone_pages
 > nr_free_pagecache_pages
 > build_all_zonelists
 > start_kernel
 > <rip> ffffffffbc164b1e next_zones_zonelist
 > <rsp> ffffffffbcc01f00

Ok, this is crashing here in next_zones_zonelist...

                while (zonelist_zone_idx(z) > highest_zoneidx)
  de:   3b 77 08                cmp    0x8(%rdi),%esi


I stuck this at the top of the function..

printk(KERN_ERR "z:%p nodes:%p highest:%d\n", z, nodes, highest_zoneidx);

and got

z: 1d08   nodes: (null)  highest:3


Some build tests show..

MAXSMP ( NODESHIFT=10 ) : Bug
NRCPUS=4 & NODESHIFT=10 : Bug
NRCPUS=4 & NODESHIFT=1 : no bug


The middle config test was accidental, I hadn't realised disabling MAXSMP
wouldn't reset NODESHIFT to something sane.

I'll start bisecting, as MAXSMP worked fine until a few days ago.

	Dave


  reply	other threads:[~2014-01-23 22:31 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-23  5:49 [PATCH] numa, mem-hotplug: Fix stack overflow in numa when seting kernel nodes to unhotpluggable Tang Chen
2014-01-23  6:01 ` Dave Jones
2014-01-23  6:05 ` Andrew Morton
2014-01-23  6:06 ` David Rientjes
2014-01-23  6:13   ` Dave Jones
2014-01-23  6:15     ` David Rientjes
2014-01-23  6:58       ` Dave Jones
2014-01-23 22:31         ` Dave Jones [this message]
2014-01-27  7:29           ` Tang Chen
2014-01-27 14:52             ` Dave Jones
2014-01-23  6:36     ` Tang Chen
2014-01-28  0:32   ` David Rientjes
2014-01-28  1:01     ` Tang Chen
2014-01-28  2:55       ` Dave Jones
2014-01-28  3:14         ` Tang Chen
2014-01-28  3:24         ` Tang Chen
2014-01-28  3:55           ` Dave Jones
2014-01-28  4:47             ` Tang Chen
2014-01-28  4:47               ` Dave Jones
2014-01-28  5:17                 ` Tang Chen
2014-01-28  6:53                   ` Dave Jones
2014-01-28  5:31                 ` Tang Chen
2014-01-28  7:10                   ` Tang Chen

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