Re: FUTEX deadlock in ping?

[Joern Nettingsmeier <nettings@folkwang-hochschule.de>]

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?