Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755187AbYFXAzR (ORCPT ); Mon, 23 Jun 2008 20:55:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751745AbYFXAzE (ORCPT ); Mon, 23 Jun 2008 20:55:04 -0400 Received: from ug-out-1314.google.com ([66.249.92.174]:2956 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751521AbYFXAzC (ORCPT ); Mon, 23 Jun 2008 20:55:02 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=tJuzFlJH5aTF6X0zRvUygBIF66VYfGRavxolL0aktcpZXJZusFSgdLXssmCynkfQ7/ bdI8Q3znaNXDG6hBme0WO5Pzk1vEKdWYpJ67VMJkPiq6YLubJukSRnm1lRwUnc/YdUI2 uMYqWV08VuLbEFn8Stbpkst2LF6yDLvGiwXk8= Date: Tue, 24 Jun 2008 04:50:53 +0400 From: Alexey Dobriyan To: "Paul E. McKenney" Cc: Linus Torvalds , Oleg Nesterov , Adrian Bunk , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org Subject: Re: [Bug #10815] 2.6.26-rc4: RIP find_pid_ns+0x6b/0xa0 Message-ID: <20080624005053.GA4827@martell.zuzino.mipt.ru> References: <20080615033001.GE26421@linux.vnet.ibm.com> <20080615162150.GA8289@martell.zuzino.mipt.ru> <20080615181710.GA17915@linux.vnet.ibm.com> <20080615232754.GD17915@linux.vnet.ibm.com> <20080616030154.GA7445@martell.zuzino.mipt.ru> <20080616033126.GF17915@linux.vnet.ibm.com> <20080616034659.GA7600@martell.zuzino.mipt.ru> <20080617034228.GA18217@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080617034228.GA18217@linux.vnet.ibm.com> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3980 Lines: 130 [rcutorture failures with PREEMPT_RCU] Status update: * bug is reproduced on another box with the very same symptoms: SMP=y, maxcpus=1 kernel occasionally fails, SMP=n is fine. Also Core 2 Duo, x86_64 [1] Race is wide -- 60 seconds of rcutorture is enough. So far tried without effect: not doing SMP-alternatives NO_HZ=y/n HIGH_RES_TIMERS=y/n compiling with gcc 3.4.6/4.1.2 different HZ s/asm/asm volatile/g at percpu asm code and PDA asm code turning on and off varying CONFIG_DEBUG_ options CONFIG_DEBUG_PREEMPT softlockup on/off making x86_64 cpu_idle() same as 32-bit one wrt rcu_pending et al sched_setaffinity() in __synchronize_sched doesn't fail Probably forgot something, but not a single thing that can remove the bug in SMP=y case. Using SMP percpu stuff for UP case miserably failed because of some hard hang due to incomplete patch, but I still leave this for doomsday. I'm going to try 32-bit setup and reading rcupreempt disassembly with microscope. [1] processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Core(TM)2 Duo CPU T7700 @ 2.40GHz stepping : 11 cpu MHz : 800.000 cache size : 4096 KB physical id : 0 siblings : 2 core id : 0 cpu cores : 2 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm ida bogomips : 4791.74 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: processor : 1 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Core(TM)2 Duo CPU T7700 @ 2.40GHz stepping : 11 cpu MHz : 800.000 cache size : 4096 KB physical id : 0 siblings : 2 core id : 1 cpu cores : 2 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm ida bogomips : 4787.76 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: ----------------------------------------------------------------------------- processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Core(TM)2 CPU 6400 @ 2.13GHz stepping : 2 cpu MHz : 2135.041 cache size : 2048 KB physical id : 0 siblings : 2 core id : 0 cpu cores : 2 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm bogomips : 4272.61 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: processor : 1 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Core(TM)2 CPU 6400 @ 2.13GHz stepping : 2 cpu MHz : 2135.041 cache size : 2048 KB physical id : 0 siblings : 2 core id : 1 cpu cores : 2 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm bogomips : 4270.14 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: -- 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/