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Message-ID: <20140627151458.27008111@gandalf.local.home>
Date: Fri, 27 Jun 2014 15:14:58 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@...achi.com>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@...achi.com>,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
linux-kernel@...r.kernel.org, yrl.pp-manager.tt@...achi.com
Subject: Re: [PATCH 1/2] trace-cmd: [BUGFIX] Initialize handle->options list
in tracecmd_attach_cpu_data_fd()
On Tue, 24 Jun 2014 02:23:43 +0000
Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@...achi.com> wrote:
> This patch initializes handle->options list in tracecmd_attach_cpu_data_fd().
>
> When recorder sends trace data via network, server recording process is
> killed by SIGSEGV from the patch 71484a0854f7. This is because add_options()
> uses handle->options list from the patch, but tracecmd_attach_cpu_data_fd()
> calling add_options() does not initialize the list in spite of allocation of
> new handle. As the result, the server recording process will be killed because
> handle->options is cleared to zero in tracecmd_attach_cpu_data_fd().
>
> <How to test>
> 1. Execute network(listen) server
> # trace-cmd listen -p 12345
>
> 2. Execute network client
> # trace-cmd record -e sched* -N <server IP>:12345
>
> 3. Stop the record on client
> ^C
>
> Here, network server should output a line "CPUX data recorded at offset=XXXX",
> but current network server aborts silently.
>
> Moreover the client's per-cpu files are separated. (Normally those files
> are merged into one trace file.)
>
> 4. Confirm error on network server
> # dmesg | tail -1
> [18551.537113] trace-cmd[23073]: segfault at ffffffffffffffe8 ip 0000000000432fd1 sp 00007fffffa4caa0 error 5 in trace-cmd[400000+47000]
>
> After we would introduce this patch, the server will be fully able to output
> the client's tracing data and we will not get this error.
>
> Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@...achi.com>
> Cc: Steven Rostedt <rostedt@...dmis.org>
Applied thanks! I also added a test to my trace-cmd test suite to check
trace-cmd listen.
-- Steve
> ---
> trace-output.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/trace-output.c b/trace-output.c
> index ed81466..b033baa 100644
> --- a/trace-output.c
> +++ b/trace-output.c
> @@ -1202,6 +1202,7 @@ int tracecmd_attach_cpu_data_fd(int fd, int cpus, char * const *cpu_data_files)
> handle->pevent = tracecmd_get_pevent(ihandle);
> pevent_ref(pevent);
> handle->page_size = tracecmd_page_size(ihandle);
> + list_head_init(&handle->options);
>
> if (tracecmd_append_cpu_data(handle, cpus, cpu_data_files) >= 0)
> ret = 0;
--
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