panic: pmap_tlb_pendcount > 0 failed

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

Hi!

I've just run a GENERIC-6.99.18/amd64 kernel from today on a newly
acquired machine, and see:

...
acpicpu11 at cpu11: ACPI CPU
panic: kernel diagnostic assertion "pmap_tlb_pendcount > 0" failed: file 
"../../../../arch/x86/x86/pmap_tlb.c", line 451
fatal breakpoint trap in supervisor mode
trap type 1 code 0 rip ffffffff802546ed cs 8 rflags 46 cr2 0 ilevel 0 rsp 
fffffe813a6369e0
curlwp 0xfffffe887556bb20 pid 0.71 lowest kstrack 0xfffffe813a633000
Stopped in pid 0.71 (system) at netbsd:breakpoint+0x5: leave
db{10}> bt
breakpoint() at netbsd:breakpoint+0x5
vpanic() at netbsd:vpanic+0x136
kern_assert() at netbsd:kern_assert+0x48
pmap_tlb_intr() at netbsd:pmap_tlb_intr+0xf4
DDB lost frame for netbsd:Xinter_lapic_tlb+0x98, trying 0xfffffe813636aa0
Xintr_lapic_tlb() at netbsd:Xinter_lapic_tlb+0x98
--- interrupt ---
246:
db{10}>

dmesg is too long to copy by hand, but available on the db prompt.
It's a Supermicro X9SRi with a Xeon E5-1650@3.20GHz.

Any ideas?
 Thomas