Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758846AbZIPOQC (ORCPT ); Wed, 16 Sep 2009 10:16:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752712AbZIPOQB (ORCPT ); Wed, 16 Sep 2009 10:16:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:29796 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752026AbZIPOQA (ORCPT ); Wed, 16 Sep 2009 10:16:00 -0400 Message-ID: <4AB0F366.6080000@redhat.com> Date: Wed, 16 Sep 2009 10:17:10 -0400 From: Masami Hiramatsu User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.1) Gecko/20090814 Fedora/3.0-2.6.b3.fc11 Thunderbird/3.0b3 MIME-Version: 1.0 To: rostedt@goodmis.org CC: Frederic Weisbecker , Ingo Molnar , lkml , systemtap , DLE , Jim Keniston , Ananth N Mavinakayanahalli , Andi Kleen , Christoph Hellwig , "Frank Ch. Eigler" , "H. Peter Anvin" , Jason Baron , "K.Prasad" , Lai Jiangshan , Li Zefan , Peter Zijlstra , Srikar Dronamraju , Tom Zanussi Subject: Re: [PATCH tracing/kprobes 2/6] ftrace: Fix trace_add_event_call() to initialize list References: <20090914204847.18779.69409.stgit@dhcp-100-2-132.bos.redhat.com> <20090914204904.18779.59422.stgit@dhcp-100-2-132.bos.redhat.com> <1253058681.20020.147.camel@gandalf.stny.rr.com> In-Reply-To: <1253058681.20020.147.camel@gandalf.stny.rr.com> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3279 Lines: 89 Steven Rostedt wrote: > On Mon, 2009-09-14 at 16:49 -0400, Masami Hiramatsu wrote: >> Initialize event_call.list and handle failuer path in trace_add_event_call() >> for fixing below bug which occurred when I tried to add invalid event twice. >> >> Could not create debugfs 'kmalloc' directory >> Failed to register kprobe event: kmalloc >> Faild to register probe event(-1) >> ------------[ cut here ]------------ >> WARNING: at /home/mhiramat/ksrc/random-tracing/lib/list_debug.c:26 >> __list_add+0x27/0x5c() >> Hardware name: >> list_add corruption. next->prev should be prev (c07d78cc), but was >> 00001000. (next=d854236c). >> Modules linked in: sunrpc uinput virtio_net virtio_balloon i2c_piix4 pcspkr >> i2c_core virtio_blk virtio_pci virtio_ring virtio [last unloaded: >> scsi_wait_scan] >> Pid: 1394, comm: tee Not tainted 2.6.31-rc9 #51 >> Call Trace: >> [] warn_slowpath_common+0x65/0x7c >> [] ? __list_add+0x27/0x5c >> [] warn_slowpath_fmt+0x24/0x27 >> [] __list_add+0x27/0x5c >> [] list_add+0xa/0xc >> [] trace_add_event_call+0x60/0x97 >> [] command_trace_probe+0x42c/0x51b >> [] ? remove_wait_queue+0x22/0x27 >> [] ? __wake_up+0x32/0x3b >> [] probes_write+0xd4/0x10a >> [] ? probes_write+0x0/0x10a >> [] vfs_write+0x80/0xdf >> [] sys_write+0x3b/0x5d >> [] syscall_call+0x7/0xb >> ---[ end trace 2b962b5dc1fdc07d ]--- >> >> Signed-off-by: Masami Hiramatsu >> Cc: Jim Keniston >> Cc: Ananth N Mavinakayanahalli >> Cc: Andi Kleen >> Cc: Christoph Hellwig >> Cc: Frank Ch. Eigler >> Cc: Frederic Weisbecker >> Cc: H. Peter Anvin >> Cc: Ingo Molnar >> Cc: Jason Baron >> Cc: K.Prasad >> Cc: Lai Jiangshan >> Cc: Li Zefan >> Cc: Peter Zijlstra >> Cc: Srikar Dronamraju >> Cc: Steven Rostedt >> Cc: Tom Zanussi >> --- >> >> kernel/trace/trace_events.c | 6 +++++- >> 1 files changed, 5 insertions(+), 1 deletions(-) >> >> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c >> index ba34920..38e82a5 100644 >> --- a/kernel/trace/trace_events.c >> +++ b/kernel/trace/trace_events.c >> @@ -1009,10 +1009,14 @@ static int __trace_add_event_call(struct ftrace_event_call *call) >> if (!d_events) >> return -ENOENT; >> >> + INIT_LIST_HEAD(&call->list); > > The INIT_LIST_HEAD is not needed here. The list_add will assign it. Without initializing it, list debugging code warns always :-) Please see, __list_add()@lib/list_debug.c Thank you, -- Masami Hiramatsu Software Engineer Hitachi Computer Products (America), Inc. Software Solutions Division e-mail: mhiramat@redhat.com -- 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/