Hi,
I have no idea what the problem could be, but maybe I will be lucky
with my suggestions.
On Fri, Apr 15, 2011 at 6:54 PM, Seth Jennings <spartacus06@xxxxxxxxx> wrote:
> There is a git-daemon segfault issue that seems to be specific to AIX.
>
> Whenever a remote user pulls or clones, the operation succeeds but
> git-daemon crashes immediately afterward.
>
> $ gdb git-daemon core
> ...
> Core was generated by `git-daemon'.
> Program terminated with signal 11, Segmentation fault.
> #0 0xd04f0c50 in _sigsetmask () from /usr/lib/libpthreads.a(shr_xpg5.o)
> (gdb) where
> #0 0xd04f0c50 in _sigsetmask () from /usr/lib/libpthreads.a(shr_xpg5.o)
> #1 0xd04f1874 in _p_sigaction () from /usr/lib/libpthreads.a(shr_xpg5.o)
> #2 0xd013ae34 in sigaction () from /usr/lib/libc.a(shr.o)
> #3 0xd0217cd8 in signal () from /usr/lib/libc.a(shr.o)
signal() is calling sigaction() so sigaction() must be called with
different parameters in your patch and when it crashes.
Could you have a look at the difference between parameters?
> #4 0x10000b90 in child_handler (signo=0) at daemon.c:718
> #5 <signal handler called>
>
> Through experimentation, I found that using sigaction() instead of
> signal() resolves the issue. I'm not entirely sure why this is.
>
> Any feedback about the issue or the patch is welcome. There might be
> a better solution.
>
> On Fri, Apr 15, 2011 at 11:51 AM, Seth Jennings <spartacus06@xxxxxxxxx> wrote:
>> This issue seems to be specific to git-daemon on AIX built with xlc.
>> After commit 695605b5080e1957bd9dab1fed35a7fee9814297 (from Aug 2008),
>> git-daemon segfaults in child_handler() inside the signal() syscall
>> immediately after any remote clone/pull operation.
Could you try some variants that revert or change parts of this commit?
For example you could revert only this hunk:
@@ -1036,11 +1032,6 @@ int main(int argc, char **argv)
gid_t gid = 0;
int i;
- /* Without this we cannot rely on waitpid() to tell
- * what happened to our children.
- */
- signal(SIGCHLD, SIG_DFL);
-
for (i = 1; i < argc; i++) {
char *arg = argv[i];
>> While it is not
>> fully understood why this happens, changing signal() to sigaction()
>> resolves the issue.
Yeah but it would be nice to understand.
Thanks in advance,
Christian.
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