From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752439AbbDBBwr (ORCPT ); Wed, 1 Apr 2015 21:52:47 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:34773 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751541AbbDBBwn (ORCPT ); Wed, 1 Apr 2015 21:52:43 -0400 Message-ID: <551CA08E.8060503@huawei.com> Date: Thu, 2 Apr 2015 09:51:10 +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> In-Reply-To: <20150401051133.GC8680@dhcp-128-53.nay.redhat.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 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. >> >> 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); Hi Dave, How about add some comment here? if set numa=off, numa_meminfo may not include all the memblock.reserved memory. e.g. trim_snb_memory() Thanks, Xishi Qiu >> + 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++) { >> > > . >