Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759485Ab3JOQke (ORCPT ); Tue, 15 Oct 2013 12:40:34 -0400 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.226]:37371 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758902Ab3JOQkc convert rfc822-to-8bit (ORCPT ); Tue, 15 Oct 2013 12:40:32 -0400 Date: Tue, 15 Oct 2013 12:40:28 -0400 From: Steven Rostedt To: "Liu, Chuansheng" Cc: "Ingo Molnar (mingo@kernel.org)" , "hpa@zytor.com" , "fweisbec@gmail.com" , "akpm@linux-foundation.org" , "paulmck@linux.vnet.ibm.com" , "Peter Zijlstra (peterz@infradead.org)" , "x86@kernel.org" , "'linux-kernel@vger.kernel.org' (linux-kernel@vger.kernel.org)" , "Wang, Xiaoming" , "Li, Zhuangzhi" Subject: Re: Panic and page fault in loop during handling NMI backtrace handler Message-ID: <20131015124028.2221e85d@gandalf.local.home> In-Reply-To: <27240C0AC20F114CBF8149A2696CBE4A01B60835@SHSMSX101.ccr.corp.intel.com> References: <27240C0AC20F114CBF8149A2696CBE4A01B60835@SHSMSX101.ccr.corp.intel.com> X-Mailer: Claws Mail 3.9.2 (GTK+ 2.24.20; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT X-RR-Connecting-IP: 107.14.168.142:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8783 Lines: 187 BTW, please do not send out HTML email, as that gets blocked from going to LKML. On Tue, 15 Oct 2013 02:01:04 +0000 "Liu, Chuansheng" wrote: > We meet one issue that during trigger all CPU backtrace, but during in the NMI handler arch_trigger_all_cpu_backtrace_handler, > It hit the PAGE fault, then PAGE fault is in loop, at last the thread stack overflow, and system panic. > > Anyone can give some help? Thanks. > > > Panic log as below: > =============== > [ 15.069144] BUG: unable to handle kernel [ 15.073635] paging request at 1649736d > [ 15.076379] IP: [] print_context_stack+0x4a/0xa0 > [ 15.082529] *pde = 00000000 > [ 15.085758] Thread overran stack, or stack corrupted > [ 15.091303] Oops: 0000 [#1] SMP > [ 15.094932] Modules linked in: atomisp_css2400b0_v2(+) lm3554 ov2722 imx1x5 atmel_mxt_ts vxd392 videobuf_vmalloc videobuf_core bcm_bt_lpm bcm43241 kct_daemon(O) > [ 15.111093] CPU: 2 PID: 2443 Comm: Compiler Tainted: G W O 3.10.1+ #1 I'm curious, what "Out-of-tree" module was loaded? Read the rest from the bottom up, as that's how I wrote it :-) > [ 15.119075] task: f213f980 ti: f0c42000 task.ti: f0c42000 > [ 15.125116] EIP: 0060:[] EFLAGS: 00210087 CPU: 2 > [ 15.131255] EIP is at print_context_stack+0x4a/0xa0 > [ 15.136712] EAX: 16497ffc EBX: 1649736d ECX: 986736d8 EDX: 1649736d > [ 15.143722] ESI: 00000000 EDI: ffffe000 EBP: f0c4220c ESP: f0c421ec > [ 15.150732] DS: 007b ES: 007b FS: 00d8 GS: 003b SS: 0068 > [ 15.156771] CR0: 80050033 CR2: 1649736d CR3: 31245000 CR4: 001007d0 > [ 15.163781] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 > [ 15.170789] DR6: ffff0ff0 DR7: 00000400 > [ 15.175076] Stack: > [ 15.177324] 16497ffc 16496000 986736d8 ffffe000 986736d8 1649736d c282c148 16496000 > [ 15.186067] f0c4223c c20033b0 c282c148 c29ceecf 00000000 f0c4222c 986736d8 f0c4222c > [ 15.194810] 00000000 c29ceecf 00000000 00000000 f0c42260 c20041a7 f0c4229c c282c148 > [ 15.203549] Call Trace: > [ 15.206295] [] dump_trace+0x70/0xf0 > [ 15.211274] [] show_trace_log_lvl+0x47/0x60 > [ 15.217028] [] show_stack_log_lvl+0x52/0xd0 > [ 15.222782] [] show_stack+0x21/0x50 > [ 15.227762] [] dump_stack+0x16/0x18 > [ 15.232742] [] warn_slowpath_common+0x5f/0x80 > [ 15.238693] [] ? vmalloc_fault+0x5a/0xcf > [ 15.244156] [] ? vmalloc_fault+0x5a/0xcf > [ 15.249621] [] ? __do_page_fault+0x4a0/0x4a0 > [ 15.255472] [] warn_slowpath_null+0x1d/0x20 > [ 15.261228] [] vmalloc_fault+0x5a/0xcf > [ 15.266497] [] __do_page_fault+0x2cf/0x4a0 > [ 15.272154] [] ? logger_aio_write+0x230/0x230 > [ 15.278106] [] ? console_unlock+0x314/0x440 > ... // > [ 16.885364] [] ? __do_page_fault+0x4a0/0x4a0 > [ 16.891217] [] do_page_fault+0x8/0x10 > [ 16.896387] [] error_code+0x5a/0x60 > [ 16.901367] [] ? __do_page_fault+0x4a0/0x4a0 > [ 16.907219] [] ? print_modules+0x20/0x90 > [ 16.912685] [] warn_slowpath_common+0x5a/0x80 > [ 16.918634] [] ? vmalloc_fault+0x5a/0xcf > [ 16.924097] [] ? vmalloc_fault+0x5a/0xcf > [ 16.929562] [] ? __do_page_fault+0x4a0/0x4a0 > [ 16.935415] [] warn_slowpath_null+0x1d/0x20 > [ 16.941169] [] vmalloc_fault+0x5a/0xcf > [ 16.946437] [] __do_page_fault+0x2cf/0x4a0 > [ 16.952095] [] ? logger_aio_write+0x230/0x230 > [ 16.958046] [] ? console_unlock+0x314/0x440 > [ 16.963800] [] ? sys_modify_ldt+0x2/0x160 > [ 16.969362] [] ? __do_page_fault+0x4a0/0x4a0 > [ 16.975215] [] do_page_fault+0x8/0x10 > [ 16.980386] [] error_code+0x5a/0x60 > [ 16.985366] [] ? __do_page_fault+0x4a0/0x4a0 > [ 16.991215] [] ? print_modules+0x20/0x90 > [ 16.996673] [] warn_slowpath_common+0x5a/0x80 > [ 17.002622] [] ? vmalloc_fault+0x5a/0xcf > [ 17.008086] [] ? vmalloc_fault+0x5a/0xcf > [ 17.013550] [] ? __do_page_fault+0x4a0/0x4a0 > [ 17.019403] [] warn_slowpath_null+0x1d/0x20 > [ 17.025159] [] vmalloc_fault+0x5a/0xcf Oh look, we are constantly warning about this same fault! There's your infinite loop. Note the WARN_ON_ONCE() does the WARN_ON() first and then updates __warned = true. Thus, if the WARN_ON() itself faults, then we are in an infinite loop. > [ 17.030428] [] __do_page_fault+0x2cf/0x4a0 > [ 17.036085] [] ? logger_aio_write+0x230/0x230 > [ 17.042037] [] ? console_unlock+0x314/0x440 > [ 17.047790] [] ? sys_modify_ldt+0x2/0x160 > [ 17.053352] [] ? __do_page_fault+0x4a0/0x4a0 > [ 17.059205] [] do_page_fault+0x8/0x10 > [ 17.064375] [] error_code+0x5a/0x60 > [ 17.069354] [] ? __do_page_fault+0x4a0/0x4a0 > [ 17.075204] [] ? print_modules+0x20/0x90 > [ 17.080669] [] warn_slowpath_common+0x5a/0x80 > [ 17.086619] [] ? vmalloc_fault+0x5a/0xcf > [ 17.092082] [] ? vmalloc_fault+0x5a/0xcf > [ 17.097546] [] ? __do_page_fault+0x4a0/0x4a0 > [ 17.103399] [] warn_slowpath_null+0x1d/0x20 > [ 17.109154] [] vmalloc_fault+0x5a/0xcf Yep, the WARN_ON() triggered in vmalloc_fault(). We shouldn't worry about warning in_nmi() for vmalloc faults anymore. > [ 17.114422] [] __do_page_fault+0x2cf/0x4a0 > [ 17.120080] [] ? update_group_power+0x1fd/0x240 > [ 17.126224] [] ? number.isra.2+0x32b/0x330 > [ 17.131880] [] ? update_curr+0xac/0x190 > [ 17.137247] [] ? number.isra.2+0x32b/0x330 > [ 17.142905] [] ? __do_page_fault+0x4a0/0x4a0 > [ 17.148755] [] do_page_fault+0x8/0x10 > [ 17.153926] [] error_code+0x5a/0x60 > [ 17.158905] [] ? __do_page_fault+0x4a0/0x4a0 > [ 17.164760] [] ? module_address_lookup+0x29/0xb0 > [ 17.170999] [] kallsyms_lookup+0x9b/0xb0 Looks like kallsyms_lookup() faulted? > [ 17.176462] [] __sprint_symbol+0x2d/0xd0 > [ 17.181926] [] ? sprintf+0x1c/0x20 > [ 17.186804] [] sprint_symbol+0x14/0x20 > [ 17.192063] [] __print_symbol+0x1e/0x40 > [ 17.197430] [] ? ashmem_shrink+0x77/0xf0 > [ 17.202895] [] ? logger_aio_write+0x230/0x230 > [ 17.208845] [] ? up+0x25/0x40 > [ 17.213242] [] ? console_unlock+0x337/0x440 > [ 17.218998] [] ? printk+0x38/0x3a > [ 17.223782] [] __show_regs+0x70/0x190 > [ 17.228954] [] show_regs+0x3a/0x1b0 > [ 17.233931] [] ? printk+0x38/0x3a > [ 17.238717] [] arch_trigger_all_cpu_backtrace_handler+0x62/0x80 > [ 17.246413] [] nmi_handle.isra.0+0x39/0x60 > [ 17.252071] [] do_nmi+0xe9/0x3f0 Start here and read upward. Can you try this patch: >From 794197cf3f563d36e5ee5b29cbf8e941163f9bc9 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Tue, 15 Oct 2013 12:34:56 -0400 Subject: [PATCH] x86: Remove WARN_ON(in_nmi()) from vmalloc_fault Since the NMI iretq nesting has been fixed, there's no reason that an NMI handler can not take a page fault for vmalloc'd code. No locks are taken in that code path, and the software now handles nested NMIs when the fault re-enables NMIs on iretq. Not only that, if the vmalloc_fault() WARN_ON_ONCE() is hit, and that warn on triggers a vmalloc fault for some reason, then we can go into an infinite loop (the WARN_ON_ONCE() does the WARN() before updating the variable to make it happen "once"). Reported-by: "Liu, Chuansheng" Signed-off-by: Steven Rostedt --- arch/x86/mm/fault.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 3aaeffc..78926c6 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -268,8 +268,6 @@ static noinline __kprobes int vmalloc_fault(unsigned long address) if (!(address >= VMALLOC_START && address < VMALLOC_END)) return -1; - WARN_ON_ONCE(in_nmi()); - /* * Synchronize this task's top level page-table * with the 'reference' page table. -- 1.8.1.4 -- 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/