Updating only libtevent causes smb_panic with Signal 11.

Issue

• Updating only libtevent causes smb_panic with Signal 11.
• samba-4.4.4-9.el7(RHEL7.3) + libtevent-0.9.31-1.el7(RHEL7.4)
  /var/log/samba/log.smbd:

[2020/10/15 11:10:31.431062,  0] ../lib/util/fault.c:78(fault_report)
  ===============================================================
[2020/10/15 11:10:31.431174,  0] ../lib/util/fault.c:79(fault_report)
  INTERNAL ERROR: Signal 11 in pid 2238 (4.4.4)
  Please read the Trouble-Shooting section of the Samba HOWTO
[2020/10/15 11:10:31.431199,  0] ../lib/util/fault.c:81(fault_report)
  ===============================================================
[2020/10/15 11:10:31.431215,  0] ../source3/lib/util.c:791(smb_panic_s3)
  PANIC (pid 2238): internal error
[2020/10/15 11:10:31.434237,  0] ../lib/util/fault.c:78(fault_report)
  ===============================================================
[2020/10/15 11:10:31.434332,  0] ../lib/util/fault.c:79(fault_report)
  INTERNAL ERROR: Signal 11 in pid 2237 (4.4.4)
  Please read the Trouble-Shooting section of the Samba HOWTO
[2020/10/15 11:10:31.434383,  0] ../lib/util/fault.c:81(fault_report)
  ===============================================================
[2020/10/15 11:10:31.434401,  0] ../source3/lib/util.c:791(smb_panic_s3)
  PANIC (pid 2237): internal error
[2020/10/15 11:10:31.434801,  0] ../source3/lib/util.c:902(log_stack_trace)
  BACKTRACE: 14 stack frames:
   #0 /lib64/libsmbconf.so.0(log_stack_trace+0x1a) [0x7f52d9dc3efa]
   #1 /lib64/libsmbconf.so.0(smb_panic_s3+0x20) [0x7f52d9dc3fd0]
   #2 /lib64/libsamba-util.so.0(smb_panic+0x2f) [0x7f52dc2b659f]
   #3 /lib64/libsamba-util.so.0(+0x247b6) [0x7f52dc2b67b6]
   #4 /lib64/libpthread.so.0(+0xf370) [0x7f52dc517370]
   #5 /lib64/libtevent.so.0(tevent_debug+0x59) [0x7f52d8800539]
   #6 /lib64/libtevent.so.0(tevent_common_loop_timer_delay+0xc1) [0x7f52d8804c81]
   #7 /lib64/libsmbconf.so.0(run_events_poll+0x1c9) [0x7f52d9dd9489]
   #8 /lib64/libsmbconf.so.0(+0x355e4) [0x7f52d9dd95e4]
   #9 /lib64/libtevent.so.0(_tevent_loop_once+0x9d) [0x7f52d88000cd]
   #10 /lib64/libtevent.so.0(tevent_req_poll+0x1f) [0x7f52d880145f]
   #11 /usr/sbin/smbd(main+0xa03) [0x7f52dc94cf03]
   #12 /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f52d845bb35]
   #13 /usr/sbin/smbd(+0x7ea6) [0x7f52dc94dea6]
[2020/10/15 11:10:31.434926,  0] ../source3/lib/dumpcore.c:303(dump_core)
  dumping core in /var/log/samba/cores/smbd
[2020/10/15 11:10:31.440471,  0] ../source3/lib/util.c:902(log_stack_trace)
  BACKTRACE: 5 stack frames:
   #0 /lib64/libsmbconf.so.0(log_stack_trace+0x1a) [0x7f52d9dc3efa]
   #1 /lib64/libsmbconf.so.0(smb_panic_s3+0x20) [0x7f52d9dc3fd0]
   #2 /lib64/libsamba-util.so.0(smb_panic+0x2f) [0x7f52dc2b659f]
   #3 /lib64/libsamba-util.so.0(+0x247b6) [0x7f52dc2b67b6]
   #4 /lib64/libpthread.so.0(+0xf370) [0x7f52dc517370]
[2020/10/15 11:10:31.440585,  0] ../source3/lib/dumpcore.c:303(dump_core)
  dumping core in /var/log/samba/cores/smbd
[2020/10/15 11:10:31.455912,  0] ../lib/util/become_daemon.c:124(daemon_ready)
  STATUS=daemon 'smbd' finished starting up and ready to serve connections
[2020/10/15 11:10:31.491181,  0] ../lib/util/fault.c:78(fault_report)
  ===============================================================
[2020/10/15 11:10:31.491297,  0] ../lib/util/fault.c:79(fault_report)
  INTERNAL ERROR: Signal 11 in pid 2241 (4.4.4)
  Please read the Trouble-Shooting section of the Samba HOWTO
[2020/10/15 11:10:31.491359,  0] ../lib/util/fault.c:81(fault_report)
  ===============================================================
[2020/10/15 11:10:31.491392,  0] ../source3/lib/util.c:791(smb_panic_s3)
  PANIC (pid 2241): internal error
[2020/10/15 11:10:31.491946,  0] ../source3/lib/util.c:902(log_stack_trace)
  BACKTRACE: 15 stack frames:
   #0 /lib64/libsmbconf.so.0(log_stack_trace+0x1a) [0x7f52d9dc3efa]
   #1 /lib64/libsmbconf.so.0(smb_panic_s3+0x20) [0x7f52d9dc3fd0]
   #2 /lib64/libsamba-util.so.0(smb_panic+0x2f) [0x7f52dc2b659f]
   #3 /lib64/libsamba-util.so.0(+0x247b6) [0x7f52dc2b67b6]
   #4 /lib64/libpthread.so.0(+0xf370) [0x7f52dc517370]
   #5 /lib64/libtalloc.so.2(talloc_get_size+0x5) [0x7f52d8a0f305]
   #6 /lib64/libsmbconf.so.0(event_add_to_poll_args+0x74) [0x7f52d9dd9064]
   #7 /lib64/libsmbconf.so.0(+0x35622) [0x7f52d9dd9622]
   #8 /lib64/libtevent.so.0(_tevent_loop_once+0x9d) [0x7f52d88000cd]
   #9 /lib64/libtevent.so.0(tevent_common_loop_wait+0x1b) [0x7f52d88002fb]
   #10 /usr/lib64/samba/libsmbd-base-samba4.so(start_background_queue+0x2a3) [0x7f52dbdce2b3]
   #11 /usr/lib64/samba/libsmbd-base-samba4.so(printing_subsystem_init+0x8b) [0x7f52dbdce58b]
   #12 /usr/sbin/smbd(main+0x11ea) [0x7f52dc94d6ea]
   #13 /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f52d845bb35]
   #14 /usr/sbin/smbd(+0x7ea6) [0x7f52dc94dea6]
...

• samba-4.4.4-9.el7(RHEL7.3) + libtevent-0.9.39-1.el7(RHEL7.8)
  /var/log/samba/log.smbd:

[2020/10/15 11:23:37.472325,  0] ../lib/util/fault.c:78(fault_report)
  ===============================================================
[2020/10/15 11:23:37.472424,  0] ../lib/util/fault.c:79(fault_report)
  INTERNAL ERROR: Signal 11 in pid 2419 (4.4.4)
  Please read the Trouble-Shooting section of the Samba HOWTO
[2020/10/15 11:23:37.472447,  0] ../lib/util/fault.c:81(fault_report)
  ===============================================================
[2020/10/15 11:23:37.472465,  0] ../source3/lib/util.c:791(smb_panic_s3)
  PANIC (pid 2419): internal error
[2020/10/15 11:23:37.472866,  0] ../source3/lib/util.c:902(log_stack_trace)
  BACKTRACE: 15 stack frames:
   #0 /lib64/libsmbconf.so.0(log_stack_trace+0x1a) [0x7fce56568efa]
   #1 /lib64/libsmbconf.so.0(smb_panic_s3+0x20) [0x7fce56568fd0]
   #2 /lib64/libsamba-util.so.0(smb_panic+0x2f) [0x7fce58a5b59f]
   #3 /lib64/libsamba-util.so.0(+0x247b6) [0x7fce58a5b7b6]
   #4 /lib64/libpthread.so.0(+0xf370) [0x7fce58cbc370]
   #5 /lib64/libtevent.so.0(tevent_common_invoke_timer_handler+0x30) [0x7fce54fa89e0]
   #6 /lib64/libtevent.so.0(tevent_common_loop_timer_delay+0x59) [0x7fce54fa8c39]
   #7 /lib64/libsmbconf.so.0(run_events_poll+0x1c9) [0x7fce5657e489]
   #8 /lib64/libsmbconf.so.0(+0x355e4) [0x7fce5657e5e4]
   #9 /lib64/libtevent.so.0(_tevent_loop_once+0xbd) [0x7fce54fa325d]
   #10 /lib64/libtevent.so.0(tevent_req_poll+0x1f) [0x7fce54fa49ff]
   #11 /usr/sbin/smbd(+0xb9a3) [0x7fce590f69a3]
   #12 /usr/sbin/smbd(main+0x8a0) [0x7fce590f1da0]
   #13 /lib64/libc.so.6(__libc_start_main+0xf5) [0x7fce54bfdb35]
   #14 /usr/sbin/smbd(+0x7ea6) [0x7fce590f2ea6]
[2020/10/15 11:23:37.472995,  0] ../source3/lib/dumpcore.c:303(dump_core)
  dumping core in /var/log/samba/cores/smbd
*** Error in `/usr/sbin/smbd': free(): invalid next size (fast): 0x00007fce5ae669e0 ***
======= Backtrace: =========
/lib64/libc.so.6(+0x7c503)[0x7fce54c58503]
/lib64/libtalloc.so.2(+0xa0c4)[0x7fce551ba0c4]
/lib64/libtalloc.so.2(+0xa01b)[0x7fce551ba01b]
/lib64/libtalloc.so.2(_talloc_free+0x123)[0x7fce551b3b63]
/lib64/libdcerpc-binding.so.0(dcerpc_binding_handle_call+0xa3)[0x7fce50bec3c3]
/usr/lib64/samba/libdcerpc-samba-samba4.so(dcerpc_winreg_OpenHKLM_r+0x1d)[0x7fce52512ecd]
/usr/lib64/samba/libdcerpc-samba-samba4.so(dcerpc_winreg_OpenHKLM+0x29)[0x7fce525130d9]
/usr/lib64/samba/libsmbd-base-samba4.so(+0xb98f5)[0x7fce585908f5]
/usr/lib64/samba/libsmbd-base-samba4.so(dcerpc_winreg_int_hklm_openkey+0x40)[0x7fce58590dd0]
/usr/lib64/samba/libsmbd-base-samba4.so(svcctl_init_winreg+0x2ca)[0x7fce586c662a]
/usr/lib64/samba/libsmbd-base-samba4.so(rpc_srv_register+0x1c6)[0x7fce586d1776]
/usr/lib64/samba/libsmbd-base-samba4.so(rpc_svcctl_init+0x30)[0x7fce586cdf70]
/usr/lib64/samba/libsmbd-base-samba4.so(dcesrv_ep_setup+0x46f)[0x7fce5867bdbf]
/usr/sbin/smbd(main+0xeb0)[0x7fce590f23b0]
/lib64/libc.so.6(__libc_start_main+0xf5)[0x7fce54bfdb35]
/usr/sbin/smbd(+0x7ea6)[0x7fce590f2ea6]
======= Memory map: ========
...

[2020/10/15 11:23:37.480438,  0] ../lib/util/fault.c:78(fault_report)
  ===============================================================
[2020/10/15 11:23:37.480500,  0] ../lib/util/fault.c:79(fault_report)
  INTERNAL ERROR: Signal 6 in pid 2417 (4.4.4)
  Please read the Trouble-Shooting section of the Samba HOWTO
[2020/10/15 11:23:37.480522,  0] ../lib/util/fault.c:81(fault_report)
  ===============================================================
[2020/10/15 11:23:37.480536,  0] ../source3/lib/util.c:791(smb_panic_s3)
  PANIC (pid 2417): internal error
[2020/10/15 11:23:37.480851,  0] ../source3/lib/util.c:902(log_stack_trace)
  BACKTRACE: 24 stack frames:
   #0 /lib64/libsmbconf.so.0(log_stack_trace+0x1a) [0x7fce56568efa]
   #1 /lib64/libsmbconf.so.0(smb_panic_s3+0x20) [0x7fce56568fd0]
   #2 /lib64/libsamba-util.so.0(smb_panic+0x2f) [0x7fce58a5b59f]
   #3 /lib64/libsamba-util.so.0(+0x247b6) [0x7fce58a5b7b6]
   #4 /lib64/libpthread.so.0(+0xf370) [0x7fce58cbc370]
   #5 /lib64/libc.so.6(gsignal+0x37) [0x7fce54c111d7]
   #6 /lib64/libc.so.6(abort+0x148) [0x7fce54c128c8]
   #7 /lib64/libc.so.6(+0x74f07) [0x7fce54c50f07]
   #8 /lib64/libc.so.6(+0x7c503) [0x7fce54c58503]
   #9 /lib64/libtalloc.so.2(+0xa0c4) [0x7fce551ba0c4]
   #10 /lib64/libtalloc.so.2(+0xa01b) [0x7fce551ba01b]
   #11 /lib64/libtalloc.so.2(_talloc_free+0x123) [0x7fce551b3b63]
   #12 /lib64/libdcerpc-binding.so.0(dcerpc_binding_handle_call+0xa3) [0x7fce50bec3c3]
   #13 /usr/lib64/samba/libdcerpc-samba-samba4.so(dcerpc_winreg_OpenHKLM_r+0x1d) [0x7fce52512ecd]
   #14 /usr/lib64/samba/libdcerpc-samba-samba4.so(dcerpc_winreg_OpenHKLM+0x29) [0x7fce525130d9]
   #15 /usr/lib64/samba/libsmbd-base-samba4.so(+0xb98f5) [0x7fce585908f5]
   #16 /usr/lib64/samba/libsmbd-base-samba4.so(dcerpc_winreg_int_hklm_openkey+0x40) [0x7fce58590dd0]
   #17 /usr/lib64/samba/libsmbd-base-samba4.so(svcctl_init_winreg+0x2ca) [0x7fce586c662a]
   #18 /usr/lib64/samba/libsmbd-base-samba4.so(rpc_srv_register+0x1c6) [0x7fce586d1776]
   #19 /usr/lib64/samba/libsmbd-base-samba4.so(rpc_svcctl_init+0x30) [0x7fce586cdf70]
   #20 /usr/lib64/samba/libsmbd-base-samba4.so(dcesrv_ep_setup+0x46f) [0x7fce5867bdbf]
   #21 /usr/sbin/smbd(main+0xeb0) [0x7fce590f23b0]
   #22 /lib64/libc.so.6(__libc_start_main+0xf5) [0x7fce54bfdb35]
   #23 /usr/sbin/smbd(+0x7ea6) [0x7fce590f2ea6]
[2020/10/15 11:23:37.481016,  0] ../source3/lib/dumpcore.c:303(dump_core)
  dumping core in /var/log/samba/cores/smbd
[2020/10/15 11:23:37.481226,  0] ../lib/util/fault.c:78(fault_report)
  ===============================================================
[2020/10/15 11:23:37.481278,  0] ../lib/util/fault.c:79(fault_report)
  INTERNAL ERROR: Signal 11 in pid 2418 (4.4.4)
  Please read the Trouble-Shooting section of the Samba HOWTO
[2020/10/15 11:23:37.481300,  0] ../lib/util/fault.c:81(fault_report)
  ===============================================================
[2020/10/15 11:23:37.481316,  0] ../source3/lib/util.c:791(smb_panic_s3)
  PANIC (pid 2418): internal error
[2020/10/15 11:23:37.481634,  0] ../source3/lib/util.c:902(log_stack_trace)
  BACKTRACE: 14 stack frames:
   #0 /lib64/libsmbconf.so.0(log_stack_trace+0x1a) [0x7fce56568efa]
   #1 /lib64/libsmbconf.so.0(smb_panic_s3+0x20) [0x7fce56568fd0]
   #2 /lib64/libsamba-util.so.0(smb_panic+0x2f) [0x7fce58a5b59f]
   #3 /lib64/libsamba-util.so.0(+0x247b6) [0x7fce58a5b7b6]
   #4 /lib64/libpthread.so.0(+0xf370) [0x7fce58cbc370]
   #5 /lib64/libtevent.so.0(tevent_common_invoke_timer_handler+0x30) [0x7fce54fa89e0]
   #6 /lib64/libtevent.so.0(tevent_common_loop_timer_delay+0x59) [0x7fce54fa8c39]
   #7 /lib64/libsmbconf.so.0(run_events_poll+0x1c9) [0x7fce5657e489]
   #8 /lib64/libsmbconf.so.0(+0x355e4) [0x7fce5657e5e4]
   #9 /lib64/libtevent.so.0(_tevent_loop_once+0xbd) [0x7fce54fa325d]
   #10 /lib64/libtevent.so.0(tevent_req_poll+0x1f) [0x7fce54fa49ff]
   #11 /usr/sbin/smbd(main+0xa03) [0x7fce590f1f03]
   #12 /lib64/libc.so.6(__libc_start_main+0xf5) [0x7fce54bfdb35]
   #13 /usr/sbin/smbd(+0x7ea6) [0x7fce590f2ea6]
[2020/10/15 11:23:37.481778,  0] ../source3/lib/dumpcore.c:303(dump_core)
  dumping core in /var/log/samba/cores/smbd