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Help : could one help decrypting 'strace' output

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eb

unread,
Mar 17, 2004, 8:05:09 AM3/17/04
to
Hello,

I have a QT based program (qgo.sourceforge.net) that crashes randomly (under
windows or linux makes no diff)

- It does not produce any core file
- It does not segfault, and the debugger does not show anything (indicates
an external signal received).

The crash occurs at calling a sound playing routine (the routine is not the
same under Windows (use of Qsound) or Linux(C routine), but both are
threaded)


I have 'valgrinded' the code, without further clue.

I have 'straced' it, but I fail to decrypt the thing.

Would anyone point me to any helpful hint ?

(BTW : yes, I have googled and read the strace man page before posting)

Thanks in advance (Hope I did not break any usenet rule)

->

read(8, "15 Game 18 I: seastory (1 175 0)"..., 4096) = 80
rt_sigprocmask(SIG_SETMASK, NULL, [RTMIN], 8) = 0
write(10, "`\20\204@\0\0\0\0\0\0\0\0P\273\16\10\220.]\10\0\0\0\200"..., 148)
= 148
rt_sigprocmask(SIG_SETMASK, NULL, [RTMIN], 8) = 0
rt_sigsuspend([] <unfinished ...>
--- SIGRTMIN (Unknown signal 32) @ 0 (0) ---
<... rt_sigsuspend resumed> ) = -1 EINTR (Interrupted system call)
sigreturn() = ? (mask now [RTMIN])
write(2, "qgo: ", 5qgo: ) = 5
write(2, "\370PI\10\2", 5øP) = 5
write(2, ": ", 2: ) = 2
open("/usr/share/locale/fr_FR/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT
(No such file or directory)
open("/usr/share/locale/fr/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No
such file or directory)
write(2, "Success\n", 8Success
) = 8
getpid() = 1528
getpid() = 1528
getpid() = 1528
write(10, "`\20\204@\2\0\0\0_\207\27\10\372\333\203@\0P\265@\300L"..., 148)
= 148
rt_sigprocmask(SIG_SETMASK, NULL, [RTMIN], 8) = 0
rt_sigsuspend([] <unfinished ...>
--- SIGRTMIN (Unknown signal 32) @ 0 (0) ---
<... rt_sigsuspend resumed> ) = -1 EINTR (Interrupted system call)
sigreturn() = ? (mask now [RTMIN])
waitpid(1529, NULL, __WCLONE) = 1529
munmap(0x4123c000, 4096) = 0
exit_group(135759711) = ?

Måns Rullgård

unread,
Mar 17, 2004, 3:18:22 PM3/17/04
to
eb <e...@nowhere.com> writes:

> Hello,
>
> I have a QT based program (qgo.sourceforge.net) that crashes randomly (under
> windows or linux makes no diff)
>
> - It does not produce any core file
> - It does not segfault, and the debugger does not show anything (indicates
> an external signal received).
>
> The crash occurs at calling a sound playing routine (the routine is not the
> same under Windows (use of Qsound) or Linux(C routine), but both are
> threaded)
>
> I have 'valgrinded' the code, without further clue.

'valground' it is.

> I have 'straced' it, but I fail to decrypt the thing.
>
> Would anyone point me to any helpful hint ?
>
> (BTW : yes, I have googled and read the strace man page before posting)

What exactly is you need help with. Is it with understanding the
strace output? In that case, which part are you having trouble with?
Otherwise it's rather clear from the trace that your program calls
exit_group, causing it to exit. Why it does that can't be determined
from the strace.

--
Måns Rullgård
m...@kth.se

eb

unread,
Mar 17, 2004, 7:12:36 PM3/17/04
to
Måns Rullgård wrote:

> eb <e...@nowhere.com> writes:
>
>> Hello,
>>
>> I have a QT based program (qgo.sourceforge.net) that crashes randomly
>> (under windows or linux makes no diff)
>>
>> - It does not produce any core file
>> - It does not segfault, and the debugger does not show anything
>> (indicates an external signal received).
>>
>> The crash occurs at calling a sound playing routine (the routine is not
>> the same under Windows (use of Qsound) or Linux(C routine), but both are
>> threaded)
>>
>> I have 'valgrinded' the code, without further clue.
>
> 'valground' it is.
>
>> I have 'straced' it, but I fail to decrypt the thing.
>>
>> Would anyone point me to any helpful hint ?
>>
>> (BTW : yes, I have googled and read the strace man page before posting)
>

Thanks for the answer

> What exactly is you need help with. Is it with understanding the
> strace output?

Yes

> In that case, which part are you having trouble with?

Everything. Call me thick.
(well, actually, not the first "read" : I know what this relates to)
There seem to be some signal fidgeting with. But I have no idea what this
means.

> Otherwise it's rather clear from the trace that your program calls
> exit_group, causing it to exit. Why it does that can't be determined
> from the strace.
>

Aahh. Sorry, but i'm so new at this.
Now .......I understand "exit_group" is a system call (but i found no doc on
this : what is it used for ?). I have of course nothing such in the code.

What tool / method should i use to get any further ?

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