I think it's best that I don't put this into the bug system. I'm too removed from the development process, and I don't have the time to build a debug version. Not sure how helpful this will be. Got the following segfault. There are two domains: domain.brandlilaw.com and domain.brandli.com. There is an external trust between them. There were, at one time, 2-4 domain controllers for each domain running buster. I upgraded domain.brandli.com a week ago and just upgraded domain.brandlilaw.com now, all 21.3. brandli.com has two domain controllers: minister1 and minister2. At the time of this segfault, brandlilaw.com had one domain controller, temple1. The command below was run on temple1. Not sure what else I can tell you. Steve root at temple1:~# samba-tool domain trust validate brandli LocalDomain Netbios[BRANDLILAW] DNS[domain.brandlilaw.com] SID[S-1-5-21-2136821272-1111453333-1140905514] LocalTDO Netbios[BRANDLI] DNS[domain.brandli.com] SID[S-1-5-21-3237397562-3087105784-2935402547] OK: LocalValidation: DC[\\minister1.domain.brandli.com] CONNECTION[WERR_OK] TRUST[WERR_OK] VERIFY_STATUS_RETURNED OK: LocalRediscover: DC[\\minister1.domain.brandli.com] CONNECTION[WERR_OK] ==============================================================INTERNAL ERROR: Signal 11: Segmentation fault in () () pid 509 (4.21.3-Debian-4.21.3+dfsg-6~bpo12+1) If you are running a recent Samba version, and if you think this problem is not yet fixed in the latest versions, please consider reporting this bug, see https://wiki.samba.org/index.php/Bug_Reporting ==============================================================PANIC (pid 509): Signal 11: Segmentation fault in 4.21.3-Debian-4.21.3+dfsg-6~bpo12+1 BACKTRACE: 37 stack frames: #0 /usr/lib/aarch64-linux-gnu/samba/libgenrand-private-samba.so.0(log_stack_trace+0x38) [0x7fff8ce51828] #1 /usr/lib/aarch64-linux-gnu/samba/libgenrand-private-samba.so.0(smb_panic+0x14) [0x7fff8ce51ae4] #2 /usr/lib/aarch64-linux-gnu/samba/libgenrand-private-samba.so.0(+0x1b7c) [0x7fff8ce51b7c] #3 linux-vdso.so.1(__kernel_rt_sigreturn+0) [0x7fff8e2287a0] #4 /usr/lib/aarch64-linux-gnu/samba/libcli-ldap-private-samba.so.0(+0x66f8) [0x7fff88e366f8] #5 /usr/lib/aarch64-linux-gnu/samba/libcli-nbt-private-samba.so.0(+0x33b4) [0x7fff884633b4] #6 /lib/aarch64-linux-gnu/libtevent.so.0(tevent_common_invoke_fd_handler+0x9c) [0x7fff8d0f791c] #7 /lib/aarch64-linux-gnu/libtevent.so.0(+0xe614) [0x7fff8d0fe614] #8 /lib/aarch64-linux-gnu/libtevent.so.0(+0xc3ec) [0x7fff8d0fc3ec] #9 /lib/aarch64-linux-gnu/libtevent.so.0(_tevent_loop_once+0x94) [0x7fff8d0f6aa4] #10 /lib/aarch64-linux-gnu/libtevent.so.0(tevent_req_poll+0x2c) [0x7fff8d0f8cac] #11 /lib/aarch64-linux-gnu/libdcerpc.so.0(finddcs_cldap_recv+0x58) [0x7fff8993fa78] #12 /lib/aarch64-linux-gnu/libdcerpc.so.0(finddcs_cldap+0x28) [0x7fff8993fb8c] #13 /usr/lib/python3/dist-packages/samba/net.cpython-311-aarch64-linux-gnu.so(+0x2948) [0x7fff86252948] #14 /usr/bin/python3() [0x4d4690] #15 /usr/bin/python3(PyObject_Vectorcall+0x44) [0x4baf34] #16 /usr/bin/python3(_PyEval_EvalFrameDefault+0x8f0) [0x4aa2c0] #17 /usr/bin/python3() [0x512454] #18 /usr/bin/python3() [0x511524] #19 /usr/bin/python3(PyObject_Call+0xac) [0x4f3120] #20 /usr/bin/python3(_PyEval_EvalFrameDefault+0x4980) [0x4ae350] #21 /usr/bin/python3() [0x512454] #22 /usr/bin/python3() [0x5114a8] #23 /usr/bin/python3(_PyEval_EvalFrameDefault+0x4980) [0x4ae350] #24 /usr/bin/python3(_PyFunction_Vectorcall+0x19c) [0x4e292c] #25 /usr/bin/python3(_PyEval_EvalFrameDefault+0x4980) [0x4ae350] #26 /usr/bin/python3(PyEval_EvalCode+0xb0) [0x4a0b90] #27 /usr/bin/python3() [0x5f9b08] #28 /usr/bin/python3() [0x5f6800] #29 /usr/bin/python3() [0x607220] #30 /usr/bin/python3(_PyRun_SimpleFileObject+0x188) [0x606dc8] #31 /usr/bin/python3(_PyRun_AnyFileObject+0x50) [0x606b30] #32 /usr/bin/python3(Py_RunMain+0x19c) [0x604dbc] #33 /usr/bin/python3(Py_BytesMain+0x24) [0x5cec14] #34 /lib/aarch64-linux-gnu/libc.so.6(+0x27740) [0x7fff8df27740] #35 /lib/aarch64-linux-gnu/libc.so.6(__libc_start_main+0x98) [0x7fff8df27818] #36 /usr/bin/python3(_start+0x30) [0x5ceab0] Aborted