Bug 278993

Summary:	fsck not checking disk if sysctl kern.boottrace.enabled=1 is set
Product:	Base System	Reporter:	Oleksii Samorukov <samm>
Component:	conf	Assignee:	freebsd-bugs (Nobody) <bugs>
Status:	Closed FIXED
Severity:	Affects Some People	CC:	imp, mhorne
Priority:	---
Version:	14.0-RELEASE
Hardware:	Any
OS:	Any

Description Oleksii Samorukov freebsd_committer

2024-05-15 05:58:52 UTC

Recently I found that some of my VPS-s fsck is not running (what is causing failed mount root in case of hard reset). 

After troubleshooting, I was able to find a root cause - it was kern.boottrace.enabled=1 in the /boot/loader.conf. This is caused by missing "$autoboot" variable in the /etc/rc.d/fsck when that script is running, so it does not run correctly. 

To reproduce on the clean system:

1. Add kern.boottrace.enabled=1 to the /boot/loader.conf
2. Add background_fsck="NO" to the /etc/rc.conf
3. Reset system and check logs. Fsck will not be started.

Comment 1 Oleksii Samorukov freebsd_committer

2024-05-15 06:05:35 UTC

Okay, so the problem is that "$autoboot" is used by the fsck script but not exported, so when the boot trace is running, the script does not work. Without a backtrace, export is not needed as the script is sourced.

Comment 2 Oleksii Samorukov freebsd_committer

2024-05-15 06:18:23 UTC

P.S. Looks like fsck is only rc.d script depending on $autoboot. Not sure if its better to export it or change fsck to no use it...

Comment 3 Oleksii Samorukov freebsd_committer

2024-05-28 14:53:31 UTC

Proposed fix is at https://github.com/freebsd/freebsd-src/pull/1261

Comment 4 Warner Losh freebsd_committer

2024-05-29 03:04:17 UTC

So part of the problem is that the boottrace stuff doesn't export any of the variables.  What about _boot or rc_fast? It looks like rc_fast is reconstructed whenver _boot is fast* in rc.subr and only set when _boot has been set to 'faststart'.

The fix is a bit of a hack.

Comment 5 commit-hook freebsd_committer

2024-05-29 19:35:03 UTC

A commit in branch main references this bug:

URL: https://cgit.FreeBSD.org/src/commit/?id=f13275cf03ae3ce220efb7a323f73290276a731f

commit f13275cf03ae3ce220efb7a323f73290276a731f
Author:     Alex Samorukov <samm@freebsd.org>
AuthorDate: 2024-05-28 14:45:30 +0000
Commit:     Warner Losh <imp@FreeBSD.org>
CommitDate: 2024-05-29 19:29:53 +0000

    export $autoboot var when running from $boottrace_cmd

    At the moment, if bootrace profiling is enabled, autoboot is not
    exported to the rc scripts. This causes fsck to not check the root
    filesystem.  To fix this, pass _boot, rc_fast and autoboot to the
    boottrace process to mimic what diretly sourcing the rc.d scripts.

    PR: 278993
    Reviewed by: imp
    Pull Request: https://github.com/freebsd/freebsd-src/pull/1261

 libexec/rc/rc.subr | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)