Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755457Ab0DESbt (ORCPT ); Mon, 5 Apr 2010 14:31:49 -0400 Received: from casper.infradead.org ([85.118.1.10]:35437 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754864Ab0DESbn (ORCPT ); Mon, 5 Apr 2010 14:31:43 -0400 Date: Mon, 5 Apr 2010 15:31:27 -0300 From: Arnaldo Carvalho de Melo To: Hitoshi Mitake Cc: Ingo Molnar , Paul Mackerras , Frederic Weisbecker , LKML Subject: Re: Floating point exception by perf record Message-ID: <20100405183127.GA3677@ghostprotocols.net> References: <4BB84991.5080301@dcl.info.waseda.ac.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4BB84991.5080301@dcl.info.waseda.ac.jp> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.19 (2009-01-05) X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2551 Lines: 65 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 -- 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/