Hi David, Thanks for the confirmation and explanation.
I will upgrade to v3.2 as suggested. Thanks for your work! Best regards, Moraxyc On Mon, Jan 05, 2026 at 11:00:21PM +0100, David Petera via Bird-users wrote: > Hi, > > we looked into it and it really is a regression bug in the v3.1.5 connected > to locking domains in BGP. > > The newly released v3.2 should not have this issue so I recommend using that > version. > Though v3.1.6 with the fix will be released also. > > Thanks a lot for reporting this bug to us! > David > > David Petera (he/him) | BIRD Tech Support | CZ.NIC, z.s.p.o. > > On 12/11/25 18:50, Moraxyc via Bird-users wrote: > > Hi BIRD Team, > > > > I wanna report a crash with BIRD 3.1.5 running on NixOS. > > > > The crash triggers a `bug()` assertion failure related to locking > > mechanisms during interface lookup (`if_find_by_index`). > > > > I have successfully reproduced this issue locally with a minimal > > configuration. > > > > Environment: > > - BIRD Version: 3.1.5 > > - OS: NixOS unstable (glibc 2.40) > > - Kernel: Linux 6.17.9 #1-NixOS SMP PREEMPT_DYNAMIC x86_64 GNU/Linux > > > > Reproduction Steps: > > 1. Configure a BGP protocol using an IPv6 Link-Local neighbor on a > > physical interface. > > 2. Start BIRD. Wait for the protocol to enter 'Active' or 'Connect' > > state so the port is listening. > > 3. Initiate a TCP connection to the BGP port: > > $ nc -6 -v <Link-Local-IP>%<interface> <port> > > 4. BIRD crashes immediately upon receiving the connection. > > > > Crash Summary (from GDB): > > The main thread (Thread 1) hits a bug() assertion: > > #3 0x000056536f6ef97a in bug (msg=<optimized out>) at > > sysdep/unix/log.c:412 > > #4 0x000056536f6fa9a1 in do_lock (dg=0x5653774ace60, > > lsp=0x7fba0208a2a8) at sysdep/unix/domain.c:116 > > #5 0x000056536f64c8ac in if_find_by_index (idx=23) at nest/iface.c:721 > > #6 0x000056536f6e4ac8 in sockaddr_read6 ... at sysdep/unix/io.c:583 > > #8 0x000056536f6ecfd7 in sk_passive_connected ... at > > sysdep/unix/io.c:1451 > > > > Attachments: > > 1. backtrace.txt: Full GDB backtrace. > > 2. config_snippet.txt: The minimal config used to reproduce the crash. > > > > Best regards, > > Moraxyc
