Bug 238883

Summary: Fatal double fault using unionfs to build www/node port (repeatable)
Product: Base System Reporter: chadf
Component: kernAssignee: freebsd-bugs (Nobody) <bugs>
Status: New ---    
Severity: Affects Only Me CC: hamiltcl
Priority: --- Keywords: panic
Version: 12.0-RELEASE   
Hardware: amd64   
OS: Any   
Attachments:
Description Flags
/var/crash/core.txt.4 file
none
/var/crash/core.txt.5 file none

Description chadf 2019-06-29 20:03:09 UTC
Created attachment 205420 [details]
/var/crash/core.txt.4 file

Repeatably able to panic kernel while building www/node ports while using nullfs and unionfs layered mounts for /usr/ports directory.

To trigger, setup mounts as:

/export/ports on /usr/ports (nullfs, local, read-only)
<above>:/usr/src/local.ports on /usr/ports (unionfs, local)

The /export/ports directory contains a master copy of the ports tree (ufs or zfs doesn't matter - haven't tried nfs).

Then build www/node port:

root@krash:~ # cd /usr/ports/www/node
root@krash:/usr/ports/www/node # make
===>  Building for node-12.4.0
   .
   .
   .

Wait for panic (may take awhile into build). After panic/reboot, restarting build panics again, almost immediately.

I was able to recreate crash in a fresh virtualbox install. The .vdi file for that VM (in a quick to re-panic state) is available upon request (7.3GB uncompressed).

/var/crash/core.txt file attached. vmcore file available (12MB compressed, unattached due to size).
Comment 1 chadf 2019-06-29 23:32:58 UTC
Replaced nullfs with symlink and still panics. Removing nullfs
Comment 2 chadf 2019-06-29 23:34:11 UTC
Replaced nullfs with symlink and still panics. Removed nullfs reference from summary line and adding core.txt.5 attachment.
Comment 3 chadf 2019-06-29 23:35:09 UTC
Created attachment 205426 [details]
/var/crash/core.txt.5 file
Comment 4 Mark Linimon freebsd_committer freebsd_triage 2019-06-30 01:09:01 UTC
The panic and any associated backtrace will be of more use than the core file.