classicupgrade fails with: PANIC: No talloc stackframe

[Andrew Bartlett]

On Fri, 2012-07-20 at 10:58 +0930, Rusty Russell wrote:
> On Thu, 19 Jul 2012 23:37:12 +1000, Andrew Bartlett <abartlet at samba.org> wrote:
> > Thanks, the critical lines are:
> > 
> > On Thu, 2012-07-19 at 15:18 +0200, Gémes Géza wrote:
> > > PANIC: No talloc stackframe
> > > ==1925== 
> > > ==1925== Process terminating with default action of signal 6 (SIGABRT)
> > > ==1925==    at 0x5F5F475: raise (raise.c:64)
> > > ==1925==    by 0x5F626EF: abort (abort.c:92)
> > > ==1925==    by 0x752ED8A: smb_panic_default (fault.c:149)
> > > ==1925==    by 0x752EDC8: smb_panic (fault.c:162)
> > > ==1925==    by 0x751FF12: _talloc_tos (talloc_stack.c:202)
> > > ==1925==    by 0x15C3F851: handle_realm (loadparm.c:6709)
> > > ==1925==    by 0x15C408C3: lp_do_parameter (loadparm.c:7113)
> > > ==1925==    by 0x15C40C0F: lp_set_cmdline_helper (loadparm.c:7198)
> > > ==1925==    by 0x15C40F32: lp_set_cmdline (loadparm.c:7238)
> > > ==1925==    by 0x6EEE4FE: lpcfg_set_cmdline (loadparm.c:2757)
> > > ==1925==    by 0x6CCCAA2: py_lp_ctx_set (pyparam.c:220)
> > > ==1925==    by 0x4EAA3A: PyEval_EvalFrameEx (in /usr/bin/python2.7)
> > > ==1925== 
> > 
> > In short, we probably need to rework the handle_realm() not to use
> > talloc_tos(). 
> 
> How about this, instead?  It insulates all the s3 parameter functions
> from such issues.
> 
> I'm spending the day with my daughter today so won't have a chance to
> test this :(  But I'm happy with this or a local handle_realm() fix;
> please apply.
> 
> (I'm a bit disappointed the testsuite doesn't run this path at all).

I've been thinking about this, and I think the real bug is returning
talloc_tos() outside the function being called.  These handle functions
are rarely called, and could either be reworked to use NULL or to add a
wrapping talloc_stackframe() inside those calls. 

(BTW, the big one of these we 'can't' fix is nt_errstr()). 

Andrew Bartlett

-- 
Andrew Bartlett                                http://samba.org/~abartlet/
Authentication Developer, Samba Team           http://samba.org