lkml.org 
[lkml]   [1999]   [Jul]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: processes stuck in skb_recv_datagram
Rob Riggs wrote:
> Multiple threads calling gethostbyname_r() (and using DNS
> to resolve) ends up with threads stuck in skb_recv_datagram.

Confirmed, I had to put a horrendously ugly hack into my threaded web
server to work around this.

All the userspace code appears correct; basically, libresolv (glibc 2.1)
checks the UDP socket with poll(), which indicates data is waiting; it
then calls some variant of recv(), which blocks indefinitely. I've only
ever been able to re-produce it under heavy load, which leads me to wildly
speculate it's a race condition in the UDP code somewhere. (Wow, Adam,
that's really helpful.) I'll try to reproduce the problem tonight on my
laptop and provide more precise information... (sure wish I could ptrace a
linuxthreads program...)

Adam
--
Your lives aren't small, but \ Adam Davenport Bradley, Grad Student
you're living them in a small \ Boston University Computer Science
way. Live openly and expansively! \ artdodge@cs.bu.edu 353-8921/MCS211
II Cor 6:12-13 (The Message) <>< \ http://www.netwinder.org/~artdodge

Hi! I'm a signature virus! Copy me into your signature so I can spread!


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:53    [W:0.040 / U:0.536 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site