[Q] t3222 sssd still showing ipa user after removed from last group

[Petr Cech]

Hi all,

I came back to ticket #3222 "sssd still showing ipa user after removed 
from last group" [1]. And I have new knowledge. But I still do not see 
the light at the end of the tunnel.

[1] https://fedorahosted.org/sssd/ticket/3222

I attached patch which enables some basic debug on using of memcache. 
And two reproducers (with and without memcache) which are based on 
reproducer written in ticket.

If we use memcache, the issue occurs only sometimes.

The difference between both cases is mixed state of switch after 
sss_nss_mc_getgrnam() call in _nss_sss_getgrnam_r() function.

Note: code says (for default case):
/* if using the mmaped cache failed,
  * fall back to socket based comms */


Could anyone help, please?


The report is:

#--- WRONG

[root@mirach sssd]# date && getent group testgroup
Wed Nov  9 16:01:05 CET 2016
> >> [A] record not found (time[1478703665])
> >> [B] record not found (time[1478703665]) 
testgroup:*:1703800674:

Number of members added 1

[root@mirach sssd]# sss_cache -UG && date && getent group testgroup
Wed Nov  9 16:01:07 CET 2016
> >> [A] record not found (time[1478703667])
> >> [B] default (time[1478703667]) 
testgroup:*:1703800674:testuser

Number of members removed 1

[root@mirach sssd]# sss_cache -UG && date && getent group testgroup
Wed Nov  9 16:01:09 CET 2016
> >> mc record expires at [1478703967] | now [1478703669]
> >> [A] MC used (time[1478703669]) 
testgroup:*:1703800674:testuser

[root@mirach sssd]# grep '>>>' *.log
sssd_nss.log:(Wed Nov  9 16:01:06 2016) [sssd[nss]] 
[sss_mmap_set_rec_header] (0x0010): >>> MC STORE expiration [1478703966] 
| now [1478703666] | delta [300]
sssd_nss.log:(Wed Nov  9 16:01:06 2016) [sssd[nss]] 
[sss_mmap_cache_gr_store] (0x0010): >>> MC STORE [testgroup] [300] 
members [0]
sssd_nss.log:(Wed Nov  9 16:01:07 2016) [sssd[nss]] 
[sss_mmap_set_rec_header] (0x0010): >>> MC STORE expiration [1478703967] 
| now [1478703667] | delta [300]
sssd_nss.log:(Wed Nov  9 16:01:07 2016) [sssd[nss]] 
[sss_mmap_cache_gr_store] (0x0010): >>> MC STORE [testgroup] [300] 
members [1]



#--- RIGHT

[root@mirach sssd]# date && getent group testgroup
Wed Nov  9 15:56:54 CET 2016
> >> [A] record not found (time[1478703414])
> >> [B] record not found (time[1478703414]) 
testgroup:*:1703800674:

Number of members added 1

[root@mirach sssd]# sss_cache -UG && date && getent group testgroup
Wed Nov  9 15:56:56 CET 2016
> >> [A] default (time[1478703416])
> >> [B] default (time[1478703416]) 
testgroup:*:1703800674:testuser

Number of members removed 1

[root@mirach sssd]# sss_cache -UG && date && getent group testgroup
Wed Nov  9 15:56:58 CET 2016
> >> [A] record not found (time[1478703418])
> >> [B] record not found (time[1478703418]) 
testgroup:*:1703800674:

[root@mirach sssd]# grep '>>>' *.log
sssd_nss.log:(Wed Nov  9 15:56:54 2016) [sssd[nss]] 
[sss_mmap_set_rec_header] (0x0010): >>> MC STORE expiration [1478703714] 
| now [1478703414] | delta [300]
sssd_nss.log:(Wed Nov  9 15:56:54 2016) [sssd[nss]] 
[sss_mmap_cache_gr_store] (0x0010): >>> MC STORE [testgroup] [300] 
members [0]
sssd_nss.log:(Wed Nov  9 15:56:56 2016) [sssd[nss]] 
[sss_mmap_set_rec_header] (0x0010): >>> MC STORE expiration [1478703716] 
| now [1478703416] | delta [300]
sssd_nss.log:(Wed Nov  9 15:56:56 2016) [sssd[nss]] 
[sss_mmap_cache_gr_store] (0x0010): >>> MC STORE [testgroup] [300] 
members [1]
sssd_nss.log:(Wed Nov  9 15:56:58 2016) [sssd[nss]] 
[sss_mmap_set_rec_header] (0x0010): >>> MC STORE expiration [1478703718] 
| now [1478703418] | delta [300]
sssd_nss.log:(Wed Nov  9 15:56:58 2016) [sssd[nss]] 
[sss_mmap_cache_gr_store] (0x0010): >>> MC STORE [testgroup] [300] 
members [0]


Regards

-- 
Petr^4 Čech