Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932219Ab0DGIcc (ORCPT ); Wed, 7 Apr 2010 04:32:32 -0400 Received: from ns.dcl.info.waseda.ac.jp ([133.9.216.194]:58246 "EHLO ns.dcl.info.waseda.ac.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754836Ab0DGIc0 (ORCPT ); Wed, 7 Apr 2010 04:32:26 -0400 Message-ID: <4BBC4318.1070702@dcl.info.waseda.ac.jp> Date: Wed, 07 Apr 2010 17:32:24 +0900 From: Hitoshi Mitake User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.5) Gecko/20091211 Shredder/3.0 MIME-Version: 1.0 To: Arnaldo Carvalho de Melo CC: Ingo Molnar , Paul Mackerras , Frederic Weisbecker , LKML Subject: Re: Floating point exception by perf record References: <4BB84991.5080301@dcl.info.waseda.ac.jp> <20100405183127.GA3677@ghostprotocols.net> In-Reply-To: <20100405183127.GA3677@ghostprotocols.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2957 Lines: 82 On 04/06/10 03:31, Arnaldo Carvalho de Melo wrote: > Em Sun, Apr 04, 2010 at 05:10:57PM +0900, Hitoshi Mitake escreveu: >> I suffered a mysterious floating point exception when executing perf >> on current tip/master. >> >> For example, >> >> % sudo ./perf lock record ./perf bench sched messaging >> # Running sched/messaging benchmark... >> # 20 sender and receiver processes per group >> # 10 groups == 400 processes run >> >> Total time: 1.375 [sec] >> [ perf record: Woken up 0 times to write data ] >> [ perf record: Captured and wrote 160.002 MB perf.data (~6990599 samples) ] >> [1] 26348 floating point exception sudo ./perf lock record ./perf >> bench sched messaging >> >> dmesg says that >> >> [10212.752490] perf[26348] trap divide error ip:7fade8564310 >> sp:7fff46d926e8 error:0 in libnewt.so.0.52.2[7fade8556000+15000] >> >> Example is of perf lock, but this is not a special phenomenon of perf lock, >> other users of perf record, like perf sched, caused the same problem. >> >> I found that this might be caused by the line 283 of perf.c >> >> if (fclose(stdout)) #<- closing stdout! >> die("close failed on standard output: %s", strerror(errno)); >> >> I don't know well about libnewt, do you know something like cause? >> >> The version of libnewt I'm using is 0.52.2 (default of Debian lenny) > > I just built a kernel where 'perf lock' can work, but I'm seeing a > different problem: > > [root@doppio ~]# perf lock trace | head -3 > Warning: Error: expected 'data' but read 'overwrite' > swapper-0 [000] 619.086424: lock_acquire: 0xffff8800029d4b28&q->lock > swapper-0 [000] 619.086429: lock_acquire: 0xffff8800029d08f8&ctx->lock > swapper-0 [000] 619.086439: lock_acquire: 0xffffffff81a38e58 clockevents_lock > [root@doppio ~]# perf lock report | head -3 > Warning: Error: expected 'data' but read 'overwrite' > ID Name acquired contended total wait (ns) max wait (ns) min wait (ns) > > 0xffff8800029d4b28&q->lock 0 0 0 0 0 > [root@doppio ~]# > > My system details: > > [root@doppio ~]# uname -a > Linux doppio.ghostprotocols.net 2.6.34-rc3-tip+ #1 SMP Mon Apr 5 13:49:42 BRT 2010 x86_64 x86_64 x86_64 GNU/Linux > [root@doppio ~]# rpm -q newt > newt-0.52.10-4.fc11.x86_64 > [root@doppio ~]# > > No segfaults here :-\ > > - Arnaldo > I tested perf lock trace and got a similar error (but different). % sudo ./perf lock trace Fatal: reading input file (size expected=3 received=0) It seems that perf.data is broken :( I'll search the cause. Hitoshi -- 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/