Hey Aurelien aweseom thanks for this! >You should try to attach gdb to the cifs.upcall process stepping through with a debugger was the "next level" i was thinking of attempting but couldnt work out how to get GDB to hook into the process. one more newbie question: I guess after i make the change in the cifs.upcall.c file i need to autoreconf /config /make /make install ? is it correct that this will overwrite all the files from the cifs-utils package on my machine? Cheers On Thu, 6 May 2021 at 14:42, Aurélien Aptel <aaptel@xxxxxxxx> wrote: > > Hi Calvin, > > Calvin Chiang <calvin.chiang@xxxxxxxxx> writes: > > Now oddly the strerror(errno) is actually returning SUCCESS > > But the pw = getpwuid(uid); is failing. > > Getpwuid(uid) is calling nss. > > ... > > > and the output from the sssd_nss.log is: > > ... > > > (Mon May 3 13:05:12 2021) [sssd[nss]] > > [cache_req_search_ncache_filter] (0x0400): CR #114: Filtering out > > results by negative cache > > > > (Mon May 3 13:05:12 2021) [sssd[nss]] [sss_ncache_check_str] > > (0x2000): Checking negative cache for > > [NCE/USER/cyberloop.local/alice@cyberloop.local] > > > > (Mon May 3 13:05:12 2021) [sssd[nss]] > > [cache_req_create_and_add_result] (0x0400): CR #114: Found 1 entries > > in domain cyberloop.local > > I don't know much about sssd but if it's finding 1 entry in the > *negative* cache that means it knows it doesn't exist. (I'm assuming > negative cache means cache of queries that have no results) > > That being said I've had issue with getpwuid() before that were solved > by updating glibc. Could be totally unrelated to your problem though. > > You should try to attach gdb to the cifs.upcall process. You can do this > by adding > > syslog(LOG_ERR, "my pid is %d", getpid()); > sleep(5); > > in cifs.upcall.c before the getpwuid() call. Then try triggering the > mount. It should block because of the sleep(). In a different terminal, > look at your system journal for the PID, and run gdb -p $pid. From there > you will be able to step into the getpwuid (glibc), nss, sss, calls. > > If your linux distribution has a debug symbol server setup for gdb to > use, gdb will dynamically fetch symbols and source code on the > fly. Otherwise you will probably need to install debug and source > packages for glibc, nss and sssd packages to be able to see function > names and source code in gdb. > > Cheers, > -- > Aurélien Aptel / SUSE Labs Samba Team > GPG: 1839 CB5F 9F5B FB9B AA97 8C99 03C8 A49B 521B D5D3 > SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg, DE > GF: Felix Imendörffer, Mary Higgins, Sri Rasiah HRB 247165 (AG München) >
