talloc-2.1.12 issues with library destructor

[Andreas Schneider]

On Saturday, 24 March 2018 22:51:58 CEST Lukas Slebodnik via samba-technical 
wrote:
> ehlo,
> 
> The latest version of libtdb changed handling of releaseing
> autofree_context. Previously, it was release with atexit and currently tith
> library destructor.
> 
> However, it caused some crashes in sssd test suite when shuttind down
> processes. In one case, there was an abort in krb5 library.
> 
>                 Stack trace of thread 19667:
>                 #0  0x00007f2cab91ff6b __GI_raise (libc.so.6)
>                 #1  0x00007f2cab90a5c1 __GI_abort (libc.so.6)
>                 #2  0x00007f2cab90a491 __assert_fail_base (libc.so.6)
>                 #3  0x00007f2cab9186e2 __GI___assert_fail (libc.so.6)
>                 #4  0x00007f2cb10aaca5 k5_mutex_lock (libkrb5.so.3)
>                 #5  0x00007f2cb10ab790 k5_mutex_lock (libkrb5.so.3)
>                 #6  0x00007f2cb10ab8f5 profile_free_file (libkrb5.so.3)
>                 #7  0x00007f2cb10ab983 profile_close_file (libkrb5.so.3)
>                 #8  0x00007f2cb10af249 profile_release (libkrb5.so.3)
>                 #9  0x00007f2cb10a06c7 k5_os_free_context (libkrb5.so.3)
>                 #10 0x00007f2cb1075a9a krb5_free_context (libkrb5.so.3)
>                 #11 0x000055cea7cb2dd1 kcm_data_destructor (sssd_kcm)
>                 #12 0x00007f2cac153e96 _tc_free_internal (libtalloc.so.2)
>                 #13 0x00007f2cac1537b0 _tc_free_internal (libtalloc.so.2)
>                 #14 0x00007f2cac1537b0 _tc_free_internal (libtalloc.so.2)
>                 #15 0x00007f2cac1537b0 _tc_free_internal (libtalloc.so.2)
>                 #16 0x00007f2cac1537b0 _tc_free_internal (libtalloc.so.2)
>                 #17 0x00007f2cac14e648 _talloc_free (libtalloc.so.2)
>                 #18 0x00007f2cac14c480 talloc_lib_fini (libtalloc.so.2)
>                 #19 0x00007f2cb151da96 _dl_fini (ld-linux-x86-64.so.2)
>                 #20 0x00007f2cab9226bc __run_exit_handlers (libc.so.6)
>                 #21 0x00007f2cab9227ec __GI_exit (libc.so.6)
>                 #22 0x00007f2cb030dc61 orderly_shutdown (libsss_util.so)
>                 #23 0x00007f2cac365a46 tevent_common_check_signal
> (libtevent.so.0) #24 0x00007f2cac367975 epoll_event_loop_once
> (libtevent.so.0) #25 0x00007f2cac365dab std_event_loop_once
> (libtevent.so.0) #26 0x00007f2cac362098 _tevent_loop_once (libtevent.so.0)
> #27 0x00007f2cac3622eb tevent_common_loop_wait (libtevent.so.0) #28
> 0x00007f2cac365d3b std_event_loop_wait (libtevent.so.0) #29
> 0x00007f2cb030eb37 server_loop (libsss_util.so) #30 0x000055cea7cb29f4 main
> (sssd_kcm)
>                 #31 0x00007f2cab90c1eb __libc_start_main (libc.so.6)
>                 #32 0x000055cea7cb2c7a _start (sssd_kcm)
> 

destructors are normally executed after the program returns from main() or 
after exit() is called. talloc tries to clean up its null context memory and 
you have obviously a talloc destructor defined for your kcm_data talloc 
context!

I don't thinks this is an issue in talloc, but sssd should cleanup the memory 
in orderly_shutdown() before it calls exit()!


The same with nss_wrapper, there is an active ldap connection which is not 
shut down correctly on exit() or when leaving main().


	Andreas

-- 
Andreas Schneider                   GPG-ID: CC014E3D
Samba Team                             asn at samba.org
www.samba.org