Re: panic: /: bad dir ino null entry

[Andy Ruhl <acruhl%gmail.com@localhost>]

On Mon, Apr 4, 2022 at 9:17 AM Bartosz Maciejewski
<bartosz%maciejewski.org@localhost> wrote:
>
> Hello,
>
> Does anybody know, how I can solve this problem below? Basically
> suddenly my NetBSD running in PV mode on XCP-NG host started rebooting
> with traceback like this:
>
> 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...
>
> I detached disks and fsck it but after connecting back to same machine
> everything started again. When I press ctrl+C just right and I cancel
> "Updating fontconfig cache" phase, it boots to login prompt. With trials
> and errors I managed to identify that /var/cache/fontconfig is directory
> that when accessed, ls, du or whatever action I take with it, its
> momentally panic :/
>
> I even created new machine from scratch and tried to rsync everything
> without /var/cache/fontconfig, and after some time, new machine started
> producing same error.
>
> I'm 100% sure all disks in SR of XCP when this VMs are, are without
> errors, even forced checked its raid didn't show any errors.
>
> While searching I stumbled upon something barely fitting my case (I
> can't find it now), that was related to rrdtool producing lots of files.
> I do have on this machine cacti with that I'm feeding with snmp data
> from other machines.
>
> So, any help or pointing to right direction will be helpfull.
>
> System is currently running with NetBSD 9.2_STABLE
>
> uname -a
> 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
>

"Lots" probably means more than cacti is producing.

This is a bug. I've run into similar panics when there is either a bad
filesystem or a bad disk. If you can, open a PR.

Andy