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Message-ID: <20140624022343.14037.69077.stgit@yuno-kbuild.novalocal>
Date: Tue, 24 Jun 2014 02:23:43 +0000
From: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@...achi.com>
To: Steven Rostedt <rostedt@...dmis.org>
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: [PATCH 1/2] trace-cmd: [BUGFIX] Initialize handle->options list in
tracecmd_attach_cpu_data_fd()
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>
---
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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