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Martin Blais
blais at furius.ca
Wed Jan 4 01:17:03 EST 2006
On 1/4/06, Graham Dumpleton <grahamd at dscpl.com.au> wrote: > Martin Blais wrote .. > > Anyway, in any case, it hangs in my own custom interpreter, and not in > > the main_interpreter. > > > > My main problem is getting more info at that point, because even if I > > attach a gdb to the cihld process, apache insists on sending it > > SIGKILL 10 seconds later. > > Which is why I suggested using "apachectl graceful" as if I read the > documentation correctly, the main Apache process will wait for the child > to exit properly. By default if ShutdownGracefulTimeout is not set or 0, > it will wait indefinitely and thus wouldn't kill it. This would allow > you time to attach gdb. > > This is of course assuming that that is how it does in fact work. :-) I know, but this is only available in apache 2.2. I think I got my hands on something here, here is what I got from a gdb backtrace when I quickly attach before the child is killed: #0 0xb7bec054 in __pthread_sigsuspend () from /lib/libpthread.so.0 #1 0xb7bebe98 in __pthread_wait_for_restart_signal () from /lib/libpthread.so.0 #2 0xb7becd6b in sem_wait@@GLIBC_2.1 () from /lib/libpthread.so.0 #3 0xb7a2a54f in PyThread_acquire_lock () from /usr/lib/apache2/modules/mod_python.so #4 0xb7a2373e in PyThreadState_Delete () from /usr/lib/apache2/modules/mod_python.so #5 0xb7a232f8 in PyInterpreterState_Delete () from /usr/lib/apache2/modules/mod_python.so #6 0xb7a24663 in Py_EndInterpreter () from /usr/lib/apache2/modules/mod_python.so #7 0xb799ff08 in python_finalize () from /usr/lib/apache2/modules/mod_python.so #8 0xb7ccb6ed in apr_pool_cleanup_run () from /usr/lib/libapr-0.so.0 #9 0xb7ccaf8d in apr_pool_destroy () from /usr/lib/libapr-0.so.0 #10 0x0806860c in ap_graceful_stop_signalled () #11 0xb7beeef5 in __pthread_sighandler () from /lib/libpthread.so.0 #12 <signal handler called> #13 0xb7b750b8 in poll () from /lib/libc.so.6 #14 0xb7ccc2af in apr_poll () from /usr/lib/libapr-0.so.0 #15 0xb7ccca53 in apr_wait_for_io_or_timeout () from /usr/lib/libapr-0.so.0 #16 0xb7cc1f74 in apr_socket_recv () from /usr/lib/libapr-0.so.0 #17 0xb7dd9335 in apr_bucket_socket_create () from /usr/lib/libaprutil-0.so.0 #18 0xb7dd9bce in apr_brigade_split_line () from /usr/lib/libaprutil-0.so.0 #19 0x0807fdfb in ap_get_request_note () #20 0x080767a6 in ap_get_brigade () #21 0xb7f3db96 in ?? () from /usr/lib/apache2/modules/mod_logio.so #22 0x08250d80 in ?? () #23 0x08272020 in ?? () #24 0x00000001 in ?? () #25 0x00000000 in ?? () Apache terminates its children by sending them a signal in the first place (#12). Then, in the Python HEAD_LOCK (Python-2.4.2/Python/pystate.c), I inspected the code and I can't find a deadlock problem. But the pthread semaphore seem to use a signal itself (the name of the call in frame #0), and we're already in a signal handler, isn't this prohibited? Can't remember just now. (more tomorrow.) good night,
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