port-xen/56782: panic: /: bad dir ino null entry

[bartosz%maciejewski.org@localhost]

>Number:         56782
>Category:       port-xen
>Synopsis:       panic: /: bad dir ino null entry
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-xen-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Apr 06 11:45:00 +0000 2022
>Originator:     Bartosz
>Release:        NetBSD 9.2_STABLE
>Organization:
>Environment:
NetBSD u-dom-fw01 9.2_STABLE NetBSD 9.2_STABLE (XEN3_DOMU) #0: Sat Jul 17 18:46:27 CEST 2021 root@u-dom-fw01:/root/sysbuild/amd64/obj/usr/src/sys/arch/amd64/compile/XEN3_DOMU amd64 
>Description:
Machine randomly reboots because of panic. After reboot it panic again on "Updating fontconfig cache" phase. CTRL+C on that phase allows it to boot again. Machine is PV domU running on XCP-NG with 2x10TB EXT storage with mdraid, which is checked to be error free. FSCKing with -f does not fix problem. Same problem is when accessing /var/cache/fontconfig dir.

Clearing temporary files.
Updating fontconfig cache:[  15.7400601] panic: /: bad dir ino 30113744 at offset 37896192: null entry

[  15.7400601] cpu0: Begin traceback...
[  15.7400601] vpanic() at netbsd:vpanic+0x143
[  15.7400601] snprintf() at netbsd:snprintf
[  15.7400601] ufs_lookup() at netbsd:ufs_lookup+0x3ba
[  15.7400601] VOP_LOOKUP() at netbsd:VOP_LOOKUP+0x34
[  15.7400601] lookup_once() at netbsd:lookup_once+0x18b
[  15.7400601] namei_tryemulroot() at netbsd:namei_tryemulroot+0x307
[  15.7400601] namei() at netbsd:namei+0x41
[  15.7400601] vn_open() at netbsd:vn_open+0x97
[  15.7400601] do_open() at netbsd:do_open+0x103
[  15.7400601] do_sys_openat() at netbsd:do_sys_openat+0x8b
[  15.7400601] sys_open() at netbsd:sys_open+0x24
[  15.7400601] syscall() at netbsd:syscall+0x9c
[  15.7400601] --- syscall (number 5) ---
[  15.7400601] 6f88f9a42a4a:
[  15.7400601] cpu0: End traceback...

[  15.7400601] dumping to dev 142,1 (offset=2097151, size=0): not possible
[  15.7400601] rebooting... 
>How-To-Repeat:
Don't know. 
>Fix: