10.99.2 panic in kern_timeout.c

[Thomas Klausner <wiz%NetBSD.org@localhost>]

Hi!

I have a new problem on a system running 10.99.2/amd64 from Jan 27,
which was heavily bulk building most of the time, and stable.

Now I have seen this panic twice today already (OCR'd so beware of typos):

panic: kernel diagnostic assertion "c->c_cpu->cc_lwp == curlwp || c->c_cu->ce_active != c" failed: file "/usr/src/sys/kern/kern_timeout.c" line 381 running callout 0xffff96631f85b80: c_func (Oxffffffff8@e070e3) c_flags (0x100) destroyed from OxfFffffff80e51f99
cpu31: Begin traceback...
vpanic() at netbsd:vpanic+0x183
kern_assert() at netbsd:kern_assert+0x4b
callout_destroy() at netbsd:callout_destroy+0xa2
timerfd_fop_close() at netbsd:timerfd_fop_close+0x36
closef() at netbsd:closef+0x60
fd_close() at netbsd:fd_close+ 0x138
sys_close() at netbsd:sys_close+0x22
syscall() at netbsd: svscall+0x196
--- syscall (number 6) ---
netbsd: syscall+0x196:
cpu31: End traceback..
fatal breakpoint trap in supervisor mode
trap type 1 code 0 rip 0xffffffff80235315 cs 0x8 rflags 0x202 cr2 0x71b8870b12dd ilevel 0 rsp 0xffffa2a133029db0

The biggest change recently is probably that my bulk build switched
from ghc92 to ghc94, but I don't know if that could cause this.

Ideas?
 Thomas