Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759074Ab3JOMhj (ORCPT ); Tue, 15 Oct 2013 08:37:39 -0400 Received: from merlin.infradead.org ([205.233.59.134]:55098 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753832Ab3JOMhi (ORCPT ); Tue, 15 Oct 2013 08:37:38 -0400 Date: Tue, 15 Oct 2013 14:37:17 +0200 From: Peter Zijlstra To: Frederic Weisbecker Cc: "Liu, Chuansheng" , Steven Rostedt , "Ingo Molnar (mingo@kernel.org)" , "hpa@zytor.com" , "akpm@linux-foundation.org" , "paulmck@linux.vnet.ibm.com" , "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: <20131015123717.GJ10651@twins.programming.kicks-ass.net> References: <27240C0AC20F114CBF8149A2696CBE4A01B60835@SHSMSX101.ccr.corp.intel.com> <20131015121849.GA29884@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131015121849.GA29884@localhost.localdomain> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 959 Lines: 18 On Tue, Oct 15, 2013 at 02:18:53PM +0200, Frederic Weisbecker wrote: > 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. IIRC modules are indeed allocated using vmalloc. See module_alloc() using vmalloc_exec() -- 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/