help with crash dump

Christos Chatzaras chris at
Mon Sep 23 16:40:25 UTC 2019

Randomly every few weeks / months one of the servers I manage gets a panic. It doesn't happen on the same server every time.

I run FreeBSD stable compiled on 2 September 2019 but it did happen with previous versions too and if I remember correctly it did happen with FreeBSD 11 too.

I don't have /usr/lib/debug/kernel files (I delete them to save some space) but I can recompile a new kernel / userland if it's needed.

Any idea what the issue is?

kgdb /boot/kernel/kernel ./vmcore.0
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Reading symbols from /boot/kernel/kernel...
(No debugging symbols found in /boot/kernel/kernel)
0xffffffff80bff56a in sched_switch ()
(kgdb) bt
#0  0xffffffff80bff56a in sched_switch ()
#1  0xffffffff80bd9be2 in mi_switch ()
#2  0xffffffff80c29175 in sleepq_catch_signals ()
#3  0xffffffff80c28caf in sleepq_wait_sig ()
#4  0xffffffff80bd960a in _sleep ()
#5  0xffffffff80c64e02 in solisten_dequeue ()
#6  0xffffffff80c6c763 in kern_accept4 ()
#7  0xffffffff80c6ca40 in accept1 ()
#8  0xffffffff810a48b4 in amd64_syscall ()
#9  <signal handler called>
#10 0x0000000800ad68ca in ?? ()
Backtrace stopped: Cannot access memory at address 0x7ffffffee648

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