pfil related panic on 6.1_STABLE

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

We hit the following panic on a recent 6.1_STABLE/amd64 server (manual OCR):

fatal page fault in supervisor mode
trap type 6 code 0 rip ffffffff804ccd44 cd 8 rflags 10212 cr2  ffff800147440128 cpl 4 rsp fffffe80010055c8
kernel: page fault trap, code=0
stopped in pid 0.3 (system) at	netbsd:memcpy+0x14:	movq	fffffffffffffff8(%rsi,%rdx,1),r10
db{0}> bt
memcpy() at netbsd:memcpy+0x14
m_copyback0() at netbsd:m_copyback0+0x22c
fr_check_wrapper() at netbsd:fr_check_wrapper+0x2e
pfil_run_hooks() at netbsd:pfil_run_hooks+0x9d
ip_output() at netbsd:ip_output+0x3fb
tcp_output() at netbsd:tcp_output+0x1542
tcp_input() at netbsd:tcp_input+0x13b6
ip_input() at netbsd:ip_input+0x43b
ipintr() at netbsd:ipintr+0x107
softint_dispatch() at netbsd:softint_dispatch+0x7b
DDB lost frame for netbsd:Xsoftintr+0x4f, trying 0xfffe8001005d70
Xsoftintr() at netbsd:Xsoftintr+0x4f
--- interrupt --
0:
db{0}> show registers
ds	55f5
es	5608
fs	55f8
gs	55b2
rdi	fffffe80eff25800
rsi	ffff800147440000
rbp	fffffe8001005600
rbx	fffffe8107d48800
rdx	130
rcx	26
rax	fffffe80eff25800
r8	fffffe80f42f5800
r9	fffffe80eff25928
r10	6572696420676e69
r11	fffffe80eff25800
r12	130
r13	fffffe80eff25800
r14	130
r14	130
rip	ffffffff804ccd44
cs	8
rflags	10212
rsp	fffffe800100rrc5
ss	10

The machine is acting as a login server and has user directories mounted from 
an NFS server we were just rebooting at the time of the panic.