Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758692Ab3JOMS7 (ORCPT ); Tue, 15 Oct 2013 08:18:59 -0400 Received: from mail-wi0-f172.google.com ([209.85.212.172]:59466 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758224Ab3JOMS6 (ORCPT ); Tue, 15 Oct 2013 08:18:58 -0400 Date: Tue, 15 Oct 2013 14:18:53 +0200 From: Frederic Weisbecker To: "Liu, Chuansheng" , Steven Rostedt Cc: "Ingo Molnar (mingo@kernel.org)" , "hpa@zytor.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: <20131015121849.GA29884@localhost.localdomain> References: <27240C0AC20F114CBF8149A2696CBE4A01B60835@SHSMSX101.ccr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <27240C0AC20F114CBF8149A2696CBE4A01B60835@SHSMSX101.ccr.corp.intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 936 Lines: 17 On Tue, Oct 15, 2013 at 02:01:04AM +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. Looks like we re-enter the fault several times. On x86-32, NMIs can fault if they dereference vmalloc'ed area. I wonder if the module thing we lookup in the NMI is stored on some vmalloc'ed area. Also, may be we enter the fault, trigger the WARN_ON_ONCE(in_nmi()) warning, which in turn dumps the stack, lookup that module address, refaults, etc... -- 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/