kernel panic: uvm_fault

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

Hi!

I had a kernel panic today with a amd64/7.99.3 kernel from Dec 20. The
last activity I had started was downloading a file from network to an
NFS directory mounted from a Synology.

I don't know if that's related, but there was no particular load on
the machine.

From dmesg after reboot:
uvm_fault(0xffffffff811cf2c0, 0xffff8003393b8000, 1) -> e
fatal page fault in supervisor mode
trap type 6 code 0 rip ffffffff8028b965 cs 8 rflags 10202 cr2 ffff8003393b8000 ilevel 4 rsp fffffe813bcb8728
curlwp 0xfffffe8825ee1220 pid 0.143 lowest kstack 0xfffffe813bcb52c0
panic: trap
cpu8: Begin traceback...
vpanic() at netbsd:vpanic+0x13c
snprintf() at netbsd:snprintf
startlwp() at netbsd:startlwp
cpu8: End traceback...


Kernel backtrace:

(gdb) bt
#0  0xffffffff80677a85 in cpu_reboot (howto=howto@entry=260, bootstr=bootstr@entry=0x0) at /archive/foreign/src/sys/arch/amd64/amd64/machdep.c:671
#1  0xffffffff808ccb54 in vpanic (fmt=fmt@entry=0xffffffff80ddb08d "trap", ap=ap@entry=0xfffffe813bcb8510) at /archive/foreign/src/sys/kern/subr_prf.c:340
#2  0xffffffff808ccc0f in panic (fmt=fmt@entry=0xffffffff80ddb08d "trap") at /archive/foreign/src/sys/kern/subr_prf.c:256
#3  0xffffffff8091bd87 in trap (frame=0xfffffe813bcb8630) at /archive/foreign/src/sys/arch/amd64/amd64/trap.c:298
#4  0xffffffff8010108e in alltraps ()
#5  0xffffffff8028b965 in .Mmbuf_inner_loop ()
#6  0xfffffe8349294000 in ?? ()
#7  0xfffffe813bcb8758 in ?? ()
#8  0xffffffff8058733e in in_delayed_cksum (m=0xffff8003393b8000) at /archive/foreign/src/sys/netinet/ip_output.c:793
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
(gdb)

Is this a valid backtrace? Does it give any useful hints?
 Thomas