Paul:
>> This may be an old topic of conversation, in which case I apologize.
>> I Googled and searched marc.theaimslist.com and Apache Bugzilla but
>> didn't see anything, so here I am with a question.
>>
>> In brief, on Linux, when doing an ungraceful stop of httpd, any
>> worker threads that are poll()ing on Keep-Alive connections don't get
>> awoken by close_worker_sockets() and that can lead to the process
>> getting the SIGKILL signal without ever getting the chance to run
>> apr_pool_destroy(pchild) in clean_child_exit(). This seems to
>> relate to this particular choice by the Linux and/or glibc folks:
>>
>> http://bugme.osdl.org/show_bug.cgi?id=546
> To clarify, are you sure its not using EPoll instead of Poll?
Well, I'll probe more deeply tomorrow, and while I'm no expert
on this stuff, I don't think so. Here are the last two lines from
an strace on one of the worker threads:
21:39:30.955670 poll([{fd=13, events=POLLIN, revents=POLLNVAL}], 1,
15000) = 1
21:39:42.257615 +++ killed by SIGKILL +++
That's the poll() on descriptor 13, for 15 keep-alive seconds,
during which the main process decides to do the SIGKILL. Here,
I think, is the accept() that opens fd 13:
21:38:51.017764 accept(3, {sa_family=AF_INET, sin_port=htons(63612),
sin_addr=inet_addr("xxx.xxx.xxx.xxx")}, [16]) = 13
and while I do see some epoll stuff, it's on another descriptor:
21:38:43.012242 epoll_create(1) = 12
Now, the caveat here is that I'm learning as I go; sockets
are not really my strong point. But it's fairly easy to reproduce
this behaviour with a stock Apache 2.0 or 2.2 on a RedHat system;
I've tried both. I can certainly provide more details if requested;
let me know! Thanks,
Chris.
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