[lttng-dev] [PATCH/babeltrace] Fix babeltrace-log crash

[Hui Zhu]

On Fri, Sep 7, 2012 at 8:37 PM, Mathieu Desnoyers
<mathieu.desnoyers at efficios.com> wrote:
> * Hui Zhu (teawater at gmail.com) wrote:
>> Hi,
>>
>> Got a crash with babeltrace-log.
>>
>> #0  0x00007ffff744504c in free () from /lib/x86_64-linux-gnu/libc.so.6
>> #1  0x00007ffff7ba6fc9 in munmap_align (mma=0x7ffff7ffe620) at
>> ../../../babeltrace/include/babeltrace/mmap-align.h:78
>> #2  0x00007ffff7ba82db in ctf_packet_seek (stream_pos=0x7fffffffde60,
>> index=0, whence=0)
>>     at ../../../babeltrace/formats/ctf/ctf.c:623
>> #3  0x00007ffff7ba8141 in ctf_init_pos (pos=0x7fffffffde60, fd=8, open_flags=2)
>>     at ../../../babeltrace/formats/ctf/ctf.c:576
>> #4  0x0000000000401146 in trace_text (output=8, input=0x7ffff7779340
>> <_IO_2_1_stdin_>)
>>     at ../../babeltrace/converter/babeltrace-log.c:233
>> #5  main (argc=<optimized out>, argv=<optimized out>) at
>> ../../babeltrace/converter/babeltrace-log.c:342
>>
>> This issue because pos is used before it init.  This patch init it in
>> function ctf_init_pos.
>
> Merged as:
>
>
> commit 36741bea2b53007c29ac0391ee9086722e00653a
> Author: Hui Zhu <teawater at gmail.com>
> Date:   Fri Sep 7 08:36:28 2012 -0400
>
>     Fix babeltrace-log uninitialized memory
>
>     Got a crash with babeltrace-log.
>
>     ../../../babeltrace/include/babeltrace/mmap-align.h:78
>     index=0, whence=0)
>         at ../../../babeltrace/formats/ctf/ctf.c:623
>         at ../../../babeltrace/formats/ctf/ctf.c:576
>     <_IO_2_1_stdin_>)
>         at ../../babeltrace/converter/babeltrace-log.c:233
>     ../../babeltrace/converter/babeltrace-log.c:342
>
>     This issue because pos is used before it init.  This patch init it in
>     function ctf_init_pos.
>
>     Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
>
> Thanks!
>
> Mathieu

Hi Mathieu,

The first one will make babeltrace crash.
Please revert it and use the second one.

Thanks,
Hui

>
>
>>
>> Thanks,
>> Hui
>>
>> --- a/formats/ctf/ctf.c
>> +++ b/formats/ctf/ctf.c
>> @@ -550,6 +550,7 @@ error:
>>
>>  void ctf_init_pos(struct ctf_stream_pos *pos, int fd, int open_flags)
>>  {
>> +     memset(pos, 0, sizeof(*pos));
>>       pos->fd = fd;
>>       if (fd >= 0) {
>>               pos->packet_cycles_index = g_array_new(FALSE, TRUE,
>>
>> _______________________________________________
>> lttng-dev mailing list
>> lttng-dev at lists.lttng.org
>> http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
>
> --
> Mathieu Desnoyers
> Operating System Efficiency R&D Consultant
> EfficiOS Inc.
> http://www.efficios.com
-------------- next part --------------
--- a/converter/babeltrace-log.c
+++ b/converter/babeltrace-log.c
@@ -230,6 +230,7 @@ void trace_text(FILE *input, int output)
 	char *line = NULL, *nl;
 	size_t linesize;
 
+	memset(&pos, 0, sizeof(pos));
 	ctf_init_pos(&pos, output, O_RDWR);
 
 	write_packet_header(&pos, s_uuid);