[Pkg-samba-maint] Bug#478752: Bug#478752: Panic or segfault inSamba

[Steve Langasek]

On Wed, May 07, 2008 at 08:41:26AM -0400, Alec Gosse wrote:
> I'm happy to second that finding.  I actually tried to run the debugging
> symbols this morning (before checking email) and it did not work :)  The
> only additional clue I've come up with on this end is that it looks like
> in at least one instance, the panic action was logged for a computer in
> the office at the same time that that person's SIP soft phone dropped a
> call.  Samba is running on the same office server as asterisk (phone pbx
> software), though I've just set asterisk to run at a higher priority
> than samba.

> Should the debugging symbols produce more than this in the panic email
> sent to me?

> The Samba 'panic action' script, /usr/share/samba/panic-action,
> was called for PID 32373 (/usr/sbin/smbd).
> Using host libthread_db library "/lib/tls/i686/cmov/libthread_db.so.1".
> [Thread debugging using libthread_db enabled]
> [New Thread -1213294912 (LWP 32373)]
> 0xb7f0a410 in ?? ()
> #0  0xb7f0a410 in ?? ()
> #1  0x00000001 in ?? ()
> #2  0x00000000 in ?? ()

Normally one would expect it to, yes.  In this case, it looks like there may
be some stack corruption, or else a gdb bug that prevents a good backtrace. 
The backtrace from your log file is much clearer and more useful:

<snip>
   #3 [0xb7fb7420]
   #4 /lib/tls/i686/cmov/libc.so.6(vsyslog+0x119) [0xb7cde679]
   #5 /lib/security/pam_unix.so(_log_err+0x8d) [0xb7815b2d]
   #6 /lib/security/pam_unix.so(pam_sm_open_session+0x109) [0xb7813519]
   #7 /lib/libpam.so.0(_pam_dispatch+0x27a) [0xb7d779ea]
   #8 /lib/libpam.so.0(pam_open_session+0x3c) [0xb7d79c7c]
<snip>

So for that, samba debugging symbols are irrelevant anyway given that the
crash is PAM-related.

What version of libpam-modules do you have on this system?  I've never seen
a crash like this before with the Debian PAM and Samba packages.

-- 
Steve Langasek                   Give me a lever long enough and a Free OS
Debian Developer                   to set it on, and I can move the world.
Ubuntu Developer                                    http://www.debian.org/
slangasek at ubuntu.com                                     vorlon at debian.org