Issue

• A customer provides email services to clients.
• sssd_nss coredumped on Apr 24, 2013, resulting in a hang of postfix.
• This caused email to be unset until postfix was manually restarted.
• Here is the stack trace:

(gdb) bt
#0  __strcmp_sse42 () at ../sysdeps/x86_64/multiarch/strcmp.S:1173
#1  0x0000000000424d8b in sss_mc_find_record (mcc=<value optimized out>, key=<value optimized out>) at src/responder/nss/nsssrv_mmap_cache.c:381
#2  0x0000000000426480 in sss_mc_get_record (_mcc=<value optimized out>, rec_len=101, key=<value optimized out>, _rec=0x7fffe3a38508) at src/responder/nss/nsssrv_mmap_cache.c:411
#3  0x0000000000426cf1 in sss_mmap_cache_pw_store (_mcc=0x18e62e0, name=0x7fffe3a38640, pw=0x7fffe3a38650, uid=2000, gid=2000, gecos=0x7fffe3a38680, homedir=0x7fffe3a38670, shell=0x7fffe3a38660)
    at src/responder/nss/nsssrv_mmap_cache.c:510
#4  0x00000000004140c5 in fill_pwent (packet=0x18f5790, dom=0x18e9f40, nctx=0x18e6250, filter_users=false, pw_mmap_cache=true, msgs=<value optimized out>, count=0x7fffe3a3874c)
    at src/responder/nss/nsssrv_cmd.c:433
#5  0x0000000000415ce8 in nss_cmd_getpw_send_reply (dctx=0x18ee0d0, filter=false) at src/responder/nss/nsssrv_cmd.c:477
#6  0x0000000000416ba8 in nss_cmd_getpwnam_dp_callback (err_maj=<value optimized out>, err_min=0, err_msg=0x18e8310 "Success", ptr=<value optimized out>) at src/responder/nss/nsssrv_cmd.c:859
#7  0x000000000040b7d4 in nsssrv_dp_send_acct_req_done (req=0x0) at src/responder/nss/nsssrv_cmd.c:643
#8  0x00000000004328ae in sss_dp_internal_get_done (pending=<value optimized out>, ptr=<value optimized out>) at src/responder/common/responder_dp.c:763
#9  0x0000003446c0e61a in complete_pending_call_and_unlock (connection=0x18eb2e0, pending=0x18f5060, message=<value optimized out>) at dbus-connection.c:2234
#10 0x0000003446c1086f in dbus_connection_dispatch (connection=0x18eb2e0) at dbus-connection.c:4397
#11 0x000000000045885e in sbus_dispatch (ev=0x18e03b0, te=<value optimized out>, tv=..., data=<value optimized out>) at src/sbus/sssd_dbus_connection.c:104
#12 0x0000003444007bd9 in tevent_common_loop_timer_delay (ev=0x18e03b0) at ../tevent_timed.c:254
#13 0x00000034440072ab in std_event_loop_once (ev=<value optimized out>, location=<value optimized out>) at ../tevent_standard.c:560
#14 0x00000034440038f0 in _tevent_loop_once (ev=0x18e03b0, location=0x4816a3 "src/util/server.c:601") at ../tevent.c:507
#15 0x000000344400395b in tevent_common_loop_wait (ev=0x18e03b0, location=0x4816a3 "src/util/server.c:601") at ../tevent.c:608
#16 0x000000000045a1b3 in server_loop (main_ctx=0x18e1530) at src/util/server.c:601
#17 0x00000000004090a0 in main (argc=<value optimized out>, argv=<value optimized out>) at src/responder/nss/nsssrv.c:564
...
(gdb) info local
rec = 0x7f789c7cbed8
hash = <value optimized out>
slot = <value optimized out>
(gdb) p *rec
Cannot access memory at address 0x7f789c7cbed8