Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752220AbbDAIjp (ORCPT ); Wed, 1 Apr 2015 04:39:45 -0400 Received: from szxga01-in.huawei.com ([58.251.152.64]:36682 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751038AbbDAIjm (ORCPT ); Wed, 1 Apr 2015 04:39:42 -0400 Message-ID: <551BADAE.4080404@huawei.com> Date: Wed, 1 Apr 2015 16:34:54 +0800 From: Xishi Qiu User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Dave Young CC: , , , , , , , Tang Chen Subject: Re: [PATCH] x86/numa: kernel stack corruption fix 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> <551BAA6D.30104@huawei.com> In-Reply-To: <551BAA6D.30104@huawei.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.25.179] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8127 Lines: 132 On 2015/4/1 16:21, Xishi Qiu wrote: > On 2015/4/1 15:41, Dave Young 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] [] 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. >> > > cc Tang Chen, numa_clear_kernel_node_hotplug() is original written by him. > > Hi Dave, > I tested the problem, and find the kdump's "numa_meminfo" is the same as the first > kernel. I did not set "numa=off" in kdump kernel, maybe this will lead to the > difference of "numa_meminfo" > Hi Dave, I find the reason, it's "dummy_numa_init() -> numa_add_memblk(0, 0, PFN_PHYS(max_pfn));", this lead to the difference of "numa_meminfo" when set "numa=off". However we should fix the bug when set "numa=off". Thanks, Xishi Qiu -- 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/