Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752771AbbDAHlr (ORCPT ); Wed, 1 Apr 2015 03:41:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49690 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751474AbbDAHlq (ORCPT ); Wed, 1 Apr 2015 03:41:46 -0400 Date: Wed, 1 Apr 2015 15:41:20 +0800 From: Dave Young To: Xishi Qiu Cc: 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 Message-ID: <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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <551B9DD7.5010603@huawei.com> User-Agent: Mutt/1.5.22.1-rc1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8483 Lines: 149 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] [] dump_stack+0x45/0x57 > >> [ 0.000000] [] panic+0xd0/0x204 > >> [ 0.000000] [] ? numa_clear_kernel_node_hotplug+0xe6/0xf2 > >> [ 0.000000] [] __stack_chk_fail+0x1b/0x20 > >> [ 0.000000] [] numa_clear_kernel_node_hotplug+0xe6/0xf2 > >> [ 0.000000] [] numa_init+0x1a5/0x520 > >> [ 0.000000] [] x86_numa_init+0x19/0x3d > >> [ 0.000000] [] initmem_init+0x9/0xb > >> [ 0.000000] [] setup_arch+0x94f/0xc82 > >> [ 0.000000] [] ? early_idt_handlers+0x120/0x120 > >> [ 0.000000] [] ? printk+0x55/0x6b > >> [ 0.000000] [] ? early_idt_handlers+0x120/0x120 > >> [ 0.000000] [] start_kernel+0xe8/0x4d6 > >> [ 0.000000] [] ? early_idt_handlers+0x120/0x120 > >> [ 0.000000] [] ? early_idt_handlers+0x120/0x120 > >> [ 0.000000] [] x86_64_start_reservations+0x2a/0x2c > >> [ 0.000000] [] 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] [] dump_stack+0x45/0x57 > >> [ 0.000000] [] early_idt_handler+0x90/0xb7 > >> [ 0.000000] [] ? native_irq_enable+0x6/0x10 > >> [ 0.000000] [] ? panic+0x1c3/0x204 > >> [ 0.000000] [] ? numa_clear_kernel_node_hotplug+0xe6/0xf2 > >> [ 0.000000] [] __stack_chk_fail+0x1b/0x20 > >> [ 0.000000] [] numa_clear_kernel_node_hotplug+0xe6/0xf2 > >> [ 0.000000] [] numa_init+0x1a5/0x520 > >> [ 0.000000] [] x86_numa_init+0x19/0x3d > >> [ 0.000000] [] initmem_init+0x9/0xb > >> [ 0.000000] [] setup_arch+0x94f/0xc82 > >> [ 0.000000] [] ? early_idt_handlers+0x120/0x120 > >> [ 0.000000] [] ? printk+0x55/0x6b > >> [ 0.000000] [] ? early_idt_handlers+0x120/0x120 > >> [ 0.000000] [] start_kernel+0xe8/0x4d6 > >> [ 0.000000] [] ? early_idt_handlers+0x120/0x120 > >> [ 0.000000] [] ? early_idt_handlers+0x120/0x120 > >> [ 0.000000] [] x86_64_start_reservations+0x2a/0x2c > >> [ 0.000000] [] 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. > > 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 > >> --- > >> 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/