Stuck CLOSED sockets / sshd / zombies...

[Karl Pielorz]

--On 11 April 2014 16:16 +0300 Konstantin Belousov <kostikbel at gmail.com> 
wrote:

> On Fri, Apr 11, 2014 at 01:39:54PM +0100, Karl Pielorz wrote:
>>
>> Ok, rebuilt a debug world (with your rtld-elf patch), installed it -
>> reproduced the issue, and ran up gdb on a 'urdlck' stuck sshd, and got
>> the  trace below.
> The trace looks reasonable.

Great :)

> I vaguelly remember that you already answered this, but I want to start
> investigating from the different angle.  Please show me the output
> of 'ldd /usr/sbin/sshd' on your machine.  This happens on stable/10,
> right ?

"
ldd /usr/sbin/sshd
/usr/sbin/sshd:
        libssh.so.5 => /usr/lib/private/libssh.so.5 (0x800860000)
        libutil.so.9 => /lib/libutil.so.9 (0x800abb000)
        libwrap.so.6 => /usr/lib/libwrap.so.6 (0x800ccd000)
        libpam.so.5 => /usr/lib/libpam.so.5 (0x800ed6000)
        libbsm.so.3 => /usr/lib/libbsm.so.3 (0x8010e2000)
        libgssapi_krb5.so.10 => /usr/lib/libgssapi_krb5.so.10 (0x8012fc000)
        libgssapi.so.10 => /usr/lib/libgssapi.so.10 (0x80151a000)
        libkrb5.so.11 => /usr/lib/libkrb5.so.11 (0x801723000)
        libhx509.so.11 => /usr/lib/libhx509.so.11 (0x801999000)
        libasn1.so.11 => /usr/lib/libasn1.so.11 (0x801be1000)
        libcom_err.so.5 => /usr/lib/libcom_err.so.5 (0x801e7a000)
        libroken.so.11 => /usr/lib/libroken.so.11 (0x80207c000)
        libwind.so.11 => /usr/lib/libwind.so.11 (0x80228d000)
        libheimbase.so.11 => /usr/lib/libheimbase.so.11 (0x8024b5000)
        libheimipcc.so.11 => /usr/lib/private/libheimipcc.so.11 
(0x8026b9000)
        libcrypt.so.5 => /lib/libcrypt.so.5 (0x8028bb000)
        libcrypto.so.7 => /lib/libcrypto.so.7 (0x802adb000)
        libz.so.6 => /lib/libz.so.6 (0x802ec6000)
        libc.so.7 => /lib/libc.so.7 (0x8030db000)
        libldns.so.5 => /usr/lib/private/libldns.so.5 (0x803474000)
        libmd.so.6 => /lib/libmd.so.6 (0x8036c8000)
        libthr.so.3 => /lib/libthr.so.3 (0x8038d8000)
"

The box is stable/10 - quite an old stable 10 now, but afaik other people 
have hit a similar issue on newer stable 10's - I've not updated this box, 
as I've seen nothing to say it's "fixed" in newer versions [and it's 
obviously been under investigation for weeks now on this machine as well, 
long before I posted to -hackers]. I can update to a newer version (e.g. 
today) if you want.

> I do not see any linking with libpthread in the sshd Makefile.  Could it
> be that libthr is loaded as dependency of some pam module ?

Possibly - I don't know. This is stock FreeBSD #10 Stable - i.e. I've not 
configured anything differently on SSH than what you get 'out the box'. 
I've never done anything with PAM - so I don't know where I'd go checking 
that kind of thing (but can if you point me in the right direction).

-Karl