hi !
disclaimer: i'm not a kernel guy ;)
after reading the FUTEX deadlock thread
(http://thread.gmane.org/gmane.linux.kernel/280900), i was wondering:
ever since moving to ldap for passwd/group/shadow/hosts lookup, ping to
a non-reachable host just freezes up and never returns:
spunk:~ # strace ping herrnilsson
execve("/bin/ping", ["ping", "herrnilsson"], [/* 61 vars */]) = 0
uname({sys="Linux", node="spunk", ...}) = 0
brk(0) = 0x8063000
...
...
munmap(0x40504000, 4096) = 0
brk(0x80a5000) = 0x80a5000
uname({sys="Linux", node="spunk", ...}) = 0
futex(0x401540f4, FUTEX_WAIT, 2, NULL
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
is this one related to the FUTEX problem olof described?
best,
j?rn
ps: i'd appreciate being cc:ed on replies. thanks.
for the record:
spunk:~ # uname -a
Linux spunk 2.6.8-24.11-smp #1 SMP Fri Jan 14 13:01:26 UTC 2005 i686
i686 i386 GNU/Linux
SuSE 9.2
problem happens also on ia32 UP (same version as before) and amd64 UP
(2.6.11-rc4-bk7)
ldap lookup is ok, for instance
spunk:~ # getent hosts herrnilsson
192.168.0.3 herrnilsson.villakunterbunt.netz herrnilsson
traceroute and others work as well.
on an otherwise identical system without ldap, ping correctly gives
"unreachable" messages.
On Thu, Feb 24, 2005 at 11:14:45AM +0100, J?rn Nettingsmeier wrote:
> ever since moving to ldap for passwd/group/shadow/hosts lookup, ping to
> a non-reachable host just freezes up and never returns:
>
> spunk:~ # strace ping herrnilsson
> execve("/bin/ping", ["ping", "herrnilsson"], [/* 61 vars */]) = 0
> uname({sys="Linux", node="spunk", ...}) = 0
> brk(0) = 0x8063000
> ...
> ...
> munmap(0x40504000, 4096) = 0
> brk(0x80a5000) = 0x80a5000
> uname({sys="Linux", node="spunk", ...}) = 0
> futex(0x401540f4, FUTEX_WAIT, 2, NULL
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Try ping -n. This is most likely something else.
--
http://www.PowerDNS.com Open source, database driven DNS Software
http://netherlabs.nl Open and Closed source services
hi bert!
thanks for your reply.
bert hubert wrote:
> On Thu, Feb 24, 2005 at 11:14:45AM +0100, J?rn Nettingsmeier wrote:
>
>
>>ever since moving to ldap for passwd/group/shadow/hosts lookup, ping to
>>a non-reachable host just freezes up and never returns:
>>
>>spunk:~ # strace ping herrnilsson
>>execve("/bin/ping", ["ping", "herrnilsson"], [/* 61 vars */]) = 0
>>uname({sys="Linux", node="spunk", ...}) = 0
>>brk(0) = 0x8063000
>>...
>>...
>>munmap(0x40504000, 4096) = 0
>>brk(0x80a5000) = 0x80a5000
>>uname({sys="Linux", node="spunk", ...}) = 0
>>futex(0x401540f4, FUTEX_WAIT, 2, NULL
>>^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
>
> Try ping -n. This is most likely something else.
>
hmm. ping -n would still have to look up the hostname, and indeed the
strace is identical (hanging). but when i ping the ip (this is probably
what you had in mind), it works as expected.
anyway, why would a process block endlessly in a futex?
On Thu, Feb 24, 2005 at 11:14:45AM +0100, J?rn Nettingsmeier wrote:
> futex(0x401540f4, FUTEX_WAIT, 2, NULL
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> is this one related to the FUTEX problem olof described?
As bert said, it's likely something else. Is the process killable, and
does "ps aux" complete? If so, then this is a different problem.
-Olof
Olof Johansson wrote:
> On Thu, Feb 24, 2005 at 11:14:45AM +0100, J?rn Nettingsmeier wrote:
>
>
>>futex(0x401540f4, FUTEX_WAIT, 2, NULL
>>^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>
>>is this one related to the FUTEX problem olof described?
>
>
> As bert said, it's likely something else. Is the process killable, and
> does "ps aux" complete?
yes and yes.
> If so, then this is a different problem.
too bad. i thought i had finally found a clue.. sorry for the noise, and
many thanks for explaining!