Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756613Ab1CXV0S (ORCPT ); Thu, 24 Mar 2011 17:26:18 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:48706 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755017Ab1CXV0R (ORCPT ); Thu, 24 Mar 2011 17:26:17 -0400 X-SecurityPolicyCheck: OK by SHieldMailChecker v1.5.1 From: Takao Indoh To: Milton Miller Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org Subject: Re: [KDUMP] Ignore spurious IPI Date: Thu, 24 Mar 2011 17:25:18 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: HidemaruMail 5.38 (WinNT,501) In-Reply-To: References: Message-Id: X-Antivirus: avast! (VPS 110324-0, 2011/03/24), Outbound message X-Antivirus-Status: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1753 Lines: 54 On Thu, 24 Mar 2011 08:20:32 -0600, Milton Miller wrote: >On Wed, 23 Mar 2011 about 18:40:12 -0000, Takao Indoh wrote: >> Hi all, >> >> I found a problem that kdump(2nd kernel) sometimes hangs up. It seems >> that system panic occurs as follows. >.. >> (2) >> A pending IPI from 1st kernel comes after unmasking interrupts at the >> following point. >> >> asmlinkage void __init start_kernel(void) >> { >> (snip) >> time_init(); >> profile_init(); >> if (!irqs_disabled()) >> printk(KERN_CRIT "start_kernel(): bug: interrupts were " >> "enabled early\n"); >> early_boot_irqs_disabled = false; >> local_irq_enable(); <=======================================HERE >> >> (3) >> Kernel tries to handle the interrupt, but some data structures are not >> initialized yet at this point. As a result, in the >> generic_smp_call_function_single_interrupt(), NULL pointer dereference >> occurs when list_replace_init() tries to access &q->list.next. >> >[tried to match lapic timer interrupt] >> Any comments? > >So this occurs because unlike device interrupts, this vector has the action >defined statically and no per-interrupt disable on your architecture? I think there is not per-interrupt disable for IPI. >If so, just initialize the data structure earlier -- change >init_call_single_data from early_initcall to an explict call after the >per-cpu areas are initialized. That makes sense. I'll do this, thanks. Thanks, Takao Indoh > >milton -- 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/