I forgot to mention: the backtrace and binary+coredump are with the
"babel bird's nest" patch included. I did test vanilla bird stable-v3.1
without the patch and it segfaults the same.
On 11/14/25 18:33, Lars Gierth via Bird-users wrote:
Hi all,
I'm migrating a bigger Babel network from Bird 2.17.x to 3.1.x. This is
on OpenWrt snapshot x86_64 with latest Bird stable-v3.1 branch. Shortly
after starting Bird, it segfaults.
I tested all the individual filter statements in my config and confirmed
it's those comparing against ifname, e.g.:
if ifname = "ts_wg0" then
It doesn't segfault if I first check for unreachable:
if dest != RTD_UNREACHABLE && ifname = "ts_wg0" then
The docs state that ifname returns an empty string for sink routes, and
that's what worked for us in 2.17.x, but maybe that broke somehow?
Anyway, with this workaround I can continue testing and rolling out.
Here's the backtrace. The config is attached and binary+coredump can be
downloaded here: https://github.com/user-attachments/files/23552707/
bird-coredump.zip Let me know if the coredump is broken, gdb did say
"memory read failed".
#0 0x00007ffff7fabd80 in ?? ()
#1 0x000000000041f881 in val_same (v1=v1@entry=0x7fffffffdb90,
v2=0x7fffffffdba8) at filter/data.c:281
#2 0x0000000000415bd7 in interpret (line=<optimized out>,
argc=argc@entry=0, argv=argv@entry=0x0, resc=resc@entry=0,
resv=resv@entry=0x0, fs=<optimized out>) at filter/f-inst.c:453
#3 0x000000000041efb6 in f_run_args (filter=0x7ffff7f31300,
rte=rte@entry=0x7fffffffe8c0, argc=argc@entry=0, argv=argv@entry=0x0,
flags=flags@entry=0) at filter/filter.c:232
#4 0x000000000041f01b in f_run (filter=<optimized out>,
rte=rte@entry=0x7fffffffe8c0, flags=flags@entry=0) at filter/filter.c:215
#5 0x000000000045c328 in channel_rte_import
(c=c@entry=0x7ffff7e61830, n=n@entry=0x7ffff7df6ea8,
new=new@entry=0x7fffffffe8c0, src=0x7ffff7e6e1c0) at nest/rt-table.c:2348
#6 0x000000000046468f in babel_rte_update_unreachable
(p=p@entry=0x7ffff7e61440, e=e@entry=0x7ffff7df6e30,
announce=announce@entry=1 '\001') at proto/babel/babel.c:698
#7 0x0000000000466c7c in babel_rt_notify (c=<optimized out>,
old=<optimized out>, P=0x7ffff7e61440, net=<optimized out>, new=0x0) at
proto/babel/babel.c:2516
#8 babel_rt_notify (P=0x7ffff7e61440, c=<optimized out>,
net=<optimized out>, new=0x0, old=<optimized out>) at proto/babel/
babel.c:2408
#9 0x00000000004581b7 in rt_notify_basic
(c=c@entry=0x7ffff7e61830, new=new@entry=0x0,
old=old@entry=0x7ffff7d983b8) at nest/rt-table.c:1250
#10 0x00000000004593ab in channel_notify_basic
(_channel=0x7ffff7e61830) at nest/rt-table.c:1661
#11 0x000000000043459b in ev_run_list_limited (l=0x53d860
<global_work_list>, limit=9, limit@entry=10) at lib/event.c:338
#12 0x00000000004a7f5d in io_loop () at sysdep/unix/io.c:2640
#13 0x00000000004037d7 in main (argc=<optimized out>,
argv=<optimized out>) at sysdep/unix/main.c:1106
Cheers, and thanks for your work!
Lars
Freifunk Berlin
