Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1753827AbbDBTPG (ORCPT <rfc822;w@1wt.eu>);
	Thu, 2 Apr 2015 15:15:06 -0400
Received: from mail-qc0-f170.google.com ([209.85.216.170]:33147 "EHLO
	mail-qc0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1753025AbbDBTPD (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Thu, 2 Apr 2015 15:15:03 -0400
Message-ID: <551d9535.87628c0a.5324.7358@mx.google.com>
Date: Thu, 02 Apr 2015 12:15:01 -0700 (PDT)
From: Yasuaki Ishimatsu <yasu.isimatu@gmail.com>
To: Dave Young <dyoung@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org, tglx@linutronix.de, bhe@redhat.com,
        mingo@redhat.com, hpa@zytor.com, akpm@linux-foundation.org
Subject: Re: [PATCH] x86/numa: kernel stack corruption fix
In-Reply-To: <20150401074120.GF8680@dhcp-128-53.nay.redhat.com>
References: <20150401045346.GA3461@dhcp-16-198.nay.redhat.com>
	<20150401051133.GC8680@dhcp-128-53.nay.redhat.com>
	<551B9DD7.5010603@huawei.com>
	<20150401074120.GF8680@dhcp-128-53.nay.redhat.com>
X-Mailer: Sylpheed 3.4.2 (GTK+ 2.10.14; i686-pc-mingw32)
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 9469
Lines: 169


On Wed, 1 Apr 2015 15:41:20 +0800
Dave Young <dyoung@redhat.com> wrote:

> On 04/01/15 at 03:27pm, Xishi Qiu wrote:
> > On 2015/4/1 13:11, Dave Young wrote:
> > 
> > > Ccing Xishi Qiu who wrote the clear_kernel_node_hotplug code.
> > > 
> > > On 04/01/15 at 12:53pm, Dave Young wrote:
> > >> I got below kernel panic during kdump test on Thinkpad T420 laptop:
> > >>
> > >> [    0.000000] No NUMA configuration found                                      
> > >> [    0.000000] Faking a node at [mem 0x0000000000000000-0x0000000037ba4fff]     
> > >> [    0.000000] Kernel panic - not syncing: stack-protector: Kernel stack is cor 
> > >> upted in: ffffffff81d21910                                                     r
> > >> [    0.000000]                                                                  
> > >> [    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.0.0-rc6+ #44           
> > >> [    0.000000] Hardware name: LENOVO 4236NUC/4236NUC, BIOS 83ET76WW (1.46 ) 07/ 
> > >> 5/2013                                                                         0
> > >> [    0.000000]  0000000000000000 c70296ddd809e4f6 ffffffff81b67ce8 ffffffff817c 
> > >> a26                                                                            2
> > >> [    0.000000]  0000000000000000 ffffffff81a61c90 ffffffff81b67d68 ffffffff817b 
> > >> 8d2                                                                            c
> > >> [    0.000000]  0000000000000010 ffffffff81b67d78 ffffffff81b67d18 c70296ddd809 
> > >> 4f6                                                                            e
> > >> [    0.000000] Call Trace:                                                      
> > >> [    0.000000]  [<ffffffff817c2a26>] dump_stack+0x45/0x57                       
> > >> [    0.000000]  [<ffffffff817bc8d2>] panic+0xd0/0x204                           
> > >> [    0.000000]  [<ffffffff81d21910>] ? numa_clear_kernel_node_hotplug+0xe6/0xf2 
> > >> [    0.000000]  [<ffffffff8107741b>] __stack_chk_fail+0x1b/0x20                 
> > >> [    0.000000]  [<ffffffff81d21910>] numa_clear_kernel_node_hotplug+0xe6/0xf2   
> > >> [    0.000000]  [<ffffffff81d21e5d>] numa_init+0x1a5/0x520                      
> > >> [    0.000000]  [<ffffffff81d222b1>] x86_numa_init+0x19/0x3d                    
> > >> [    0.000000]  [<ffffffff81d22460>] initmem_init+0x9/0xb                       
> > >> [    0.000000]  [<ffffffff81d0d00c>] setup_arch+0x94f/0xc82                     
> > >> [    0.000000]  [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120           
> > >> [    0.000000]  [<ffffffff817bd0bb>] ? printk+0x55/0x6b                         
> > >> [    0.000000]  [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120           
> > >> [    0.000000]  [<ffffffff81d05d9b>] start_kernel+0xe8/0x4d6                    
> > >> [    0.000000]  [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120           
> > >> [    0.000000]  [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120           
> > >> [    0.000000]  [<ffffffff81d055ee>] x86_64_start_reservations+0x2a/0x2c        
> > >> [    0.000000]  [<ffffffff81d05751>] x86_64_start_kernel+0x161/0x184            
> > >> [    0.000000] ---[ end Kernel panic - not syncing: stack-protector: Kernel sta 
> > >> k is corrupted in: ffffffff81d21910                                            c
> > >> [    0.000000]                                                                  
> > >> PANIC: early exception 0d rip 10:ffffffff8105d2a6 error 7eb cr2 ffff8800371dd00 
> > >> [    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.0.0-rc6+ #44          0
> > >> [    0.000000] Hardware name: LENOVO 4236NUC/4236NUC, BIOS 83ET76WW (1.46 ) 07/ 
> > >> 5/2013                                                                         0
> > >> [    0.000000]  0000000000000000 c70296ddd809e4f6 ffffffff81b67c60 ffffffff817c 
> > >> a26                                                                            2
> > >> [    0.000000]  0000000000000096 ffffffff81a61c90 ffffffff81b67d68 fffffff00000 
> > >> 084 0000000000000a0d 0000000000000a00                                          0
> > >> [    0.000000] Call Trace:                                                      
> > >> [    0.000000]  [<ffffffff817c2a26>] dump_stack+0x45/0x57                       
> > >> [    0.000000]  [<ffffffff81d051b0>] early_idt_handler+0x90/0xb7                
> > >> [    0.000000]  [<ffffffff8105d2a6>] ? native_irq_enable+0x6/0x10               
> > >> [    0.000000]  [<ffffffff817bc9c5>] ? panic+0x1c3/0x204                        
> > >> [    0.000000]  [<ffffffff81d21910>] ? numa_clear_kernel_node_hotplug+0xe6/0xf2 
> > >> [    0.000000]  [<ffffffff8107741b>] __stack_chk_fail+0x1b/0x20                 
> > >> [    0.000000]  [<ffffffff81d21910>] numa_clear_kernel_node_hotplug+0xe6/0xf2   
> > >> [    0.000000]  [<ffffffff81d21e5d>] numa_init+0x1a5/0x520                      
> > >> [    0.000000]  [<ffffffff81d222b1>] x86_numa_init+0x19/0x3d                    
> > >> [    0.000000]  [<ffffffff81d22460>] initmem_init+0x9/0xb                       
> > >> [    0.000000]  [<ffffffff81d0d00c>] setup_arch+0x94f/0xc82                     
> > >> [    0.000000]  [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120           
> > >> [    0.000000]  [<ffffffff817bd0bb>] ? printk+0x55/0x6b                         
> > >> [    0.000000]  [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120           
> > >> [    0.000000]  [<ffffffff81d05d9b>] start_kernel+0xe8/0x4d6                    
> > >> [    0.000000]  [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120           
> > >> [    0.000000]  [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120           
> > >> [    0.000000]  [<ffffffff81d055ee>] x86_64_start_reservations+0x2a/0x2c        
> > >> [    0.000000]  [<ffffffff81d05751>] x86_64_start_kernel+0x161/0x184            
> > >> [    0.000000] RIP 0x46                                                         
> > >>
> > >> This is caused by writing over end of numa mask bitmap.
> > >>
> > >> numa_clear_kernel_node try to set node id in a mask bitmap, it iterating all
> > >> reserved region and assume every regions have valid nid. It is not true because
> > >> There's an exception for graphic memory quirks. see function trim_snb_memory
> > >> in arch/x86/kernel/setup.c
> > >>
> > >> It is easily to reproduce the bug in kdump kernel because kdump kernel use
> > >> prereserved memory instead of whole memory, but kexec pass other reserved memory
> > >> ranges to 2nd kernel as well. like below in my test:
> > >> kdump kernel ram 0x2d000000 - 0x37bfffff
> > >> One of the reserved regions: 0x40000000 - 0x40100000
> > >>
> > >> The above reserved region includes 0x40004000, a page excluded in
> > >> trim_snb_memory. For this memblock reserved region the nid is not set it is
> > >> still default value MAX_NUMNODES. later node_set callback will set bit
> > >> MAX_NUMNODES in nodemask bitmap thus stack corruption happen. 
> > >>
> > 
> > Hi Dave,
> > 
> > Is it means, first reserved region 0x40000000 - 0x40100000, then boot the kdump
> > kernel, so this region is not include in "numa_meminfo", and memblock.reserved
> > (0x40004000) is still MAX_NUMNODES from trim_snb_memory().
> 
> Right, btw, I booted kdump kernel with numa=off for saving memory.
> 
> I suspect it will also be reproduced with mem=XYZ with normal kernel.

Does the issue occur on your system with mem=0x40000000?

I think the issue occurs when reserved memory range is not includes
in system ram which informed by e820 or SRAT table. On your system,
0x40004000 is reserved by trim_snb_memory(). But if you use mem=0x40000000,
the system ram is limited within 0x40000000. So the issue will occur.

Thanks,
Yasuaki Ishimatsu

> 
> > 
> > numa_clear_kernel_node_hotplug
> > {
> > 	...
> > 	for (i = 0; i < numa_meminfo.nr_blks; i++) {
> > 		struct numa_memblk *mb = &numa_meminfo.blk[i];
> > 
> > 		memblock_set_node(mb->start, mb->end - mb->start,
> > 				  &memblock.reserved, mb->nid);  // this will not reset 0x40004000's node, right?
> > 	}
> > 	...
> > }
> > 
> > Thanks
> > Xishi Qiu
> > 
> > >> Fixing this by adding a check, do not call node_set in case nid is MAX_NUMNODES.
> > >>
> > >> Signed-off-by: Dave Young <dyoung@redhat.com>
> > >> ---
> > >>  arch/x86/mm/numa.c |    3 ++-
> > >>  1 file changed, 2 insertions(+), 1 deletion(-)
> > >>
> > >> --- linux.orig/arch/x86/mm/numa.c
> > >> +++ linux/arch/x86/mm/numa.c
> > >> @@ -484,7 +484,8 @@ static void __init numa_clear_kernel_nod
> > >>  
> > >>  	/* Mark all kernel nodes. */
> > >>  	for_each_memblock(reserved, r)
> > >> -		node_set(r->nid, numa_kernel_nodes);
> > >> +		if (r->nid != MAX_NUMNODES)
> > >> +			node_set(r->nid, numa_kernel_nodes);
> > >>  
> > >>  	/* Clear MEMBLOCK_HOTPLUG flag for memory in kernel nodes. */
> > >>  	for (i = 0; i < numa_meminfo.nr_blks; i++) {
> > >>
> > > 
> > > .
> > > 
> > 
> > 
> > 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/