Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761431AbXJOQFV (ORCPT ); Mon, 15 Oct 2007 12:05:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757582AbXJOQFF (ORCPT ); Mon, 15 Oct 2007 12:05:05 -0400 Received: from smtp4-g19.free.fr ([212.27.42.30]:60533 "EHLO smtp4-g19.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755741AbXJOQFD (ORCPT ); Mon, 15 Oct 2007 12:05:03 -0400 Message-ID: <47138FAD.8050805@free.fr> Date: Mon, 15 Oct 2007 18:05:01 +0200 From: John Sigler User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.8) Gecko/20061108 SeaMonkey/1.0.6 MIME-Version: 1.0 To: Arjan van de Ven CC: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Subject: Re: NMI watchdog References: <470F3BE0.4050807@free.fr> <20071012074836.79e6a064@laptopd505.fenrus.org> In-Reply-To: <20071012074836.79e6a064@laptopd505.fenrus.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2649 Lines: 89 Arjan van de Ven wrote: > John Sigler wrote: > >> I'm experiencing a full system lockup. I'm using an out-of-tree >> driver which I suspect is responsible. I'm trying to enable the NMI >> watchdog. > > one thing worth a shot is enabling lockdep.. that often finds deadlocks > for you ;) I enabled every option I thought might be useful. I booted the system, fired a serial console, bumped the priority of the serial port IRQ handler to 80 and the priority of the shell in the serial console to 70, set the console log level to 9 using SysRq. I then connected via ssh, loaded the driver module (the output showed up in the serial console), started 4 processes, and had a complete system lock-up within 10 seconds. Nothing on the serial console :-( The system didn't even respond to SysRq... How do kernel hackers debug these problems? # # Kernel hacking # CONFIG_TRACE_IRQFLAGS_SUPPORT=y # CONFIG_PRINTK_TIME is not set # CONFIG_ENABLE_MUST_CHECK is not set CONFIG_MAGIC_SYSRQ=y # CONFIG_UNUSED_SYMBOLS is not set # CONFIG_DEBUG_FS is not set # CONFIG_HEADERS_CHECK is not set CONFIG_DEBUG_KERNEL=y CONFIG_DEBUG_SHIRQ=y CONFIG_DETECT_SOFTLOCKUP=y CONFIG_SCHED_DEBUG=y # CONFIG_SCHEDSTATS is not set CONFIG_TIMER_STATS=y CONFIG_DEBUG_SLAB=y CONFIG_DEBUG_SLAB_LEAK=y CONFIG_DEBUG_PREEMPT=y CONFIG_DEBUG_RT_MUTEXES=y CONFIG_DEBUG_PI_LIST=y # CONFIG_RT_MUTEX_TESTER is not set CONFIG_DEBUG_SPINLOCK=y CONFIG_DEBUG_MUTEXES=y CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y CONFIG_LOCKDEP=y # CONFIG_LOCK_STAT is not set # CONFIG_DEBUG_LOCKDEP is not set CONFIG_TRACE_IRQFLAGS=y CONFIG_DEBUG_SPINLOCK_SLEEP=y CONFIG_DEBUG_LOCKING_API_SELFTESTS=y CONFIG_STACKTRACE=y CONFIG_PREEMPT_TRACE=y # CONFIG_EVENT_TRACE is not set # CONFIG_FUNCTION_TRACE is not set # CONFIG_WAKEUP_TIMING is not set # CONFIG_CRITICAL_PREEMPT_TIMING is not set # CONFIG_CRITICAL_IRQSOFF_TIMING is not set # CONFIG_DEBUG_KOBJECT is not set CONFIG_DEBUG_BUGVERBOSE=y # CONFIG_DEBUG_INFO is not set # CONFIG_DEBUG_VM is not set # CONFIG_DEBUG_LIST is not set # CONFIG_FRAME_POINTER is not set CONFIG_FORCED_INLINING=y # CONFIG_RCU_TORTURE_TEST is not set # CONFIG_FAULT_INJECTION is not set CONFIG_EARLY_PRINTK=y CONFIG_DEBUG_STACKOVERFLOW=y # CONFIG_DEBUG_STACK_USAGE is not set # CONFIG_DEBUG_PAGEALLOC is not set CONFIG_DEBUG_RODATA=y CONFIG_4KSTACKS=y CONFIG_X86_FIND_SMP_CONFIG=y CONFIG_X86_MPPARSE=y CONFIG_DOUBLEFAULT=y - 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/