Bug 240451

Summary:	Boot problem from disk on older Intel hardware (kern.vty="vt")
Product:	Base System	Reporter:	bartsch
Component:	misc	Assignee:	freebsd-bugs (Nobody) <bugs>
Status:	Closed Not A Bug
Severity:	Affects Some People
Priority:	---
Version:	12.0-STABLE
Hardware:	amd64
OS:	Any

Description bartsch 2019-09-09 16:39:14 UTC

We are testing FreeBSD 12.0-STABLE on some of our servers to prepare migration from FreeBSD-10 to FreeBSD-12.
Our current svn info:
URL: svn://svn.freebsd.org/base/stable/12
Relative URL: ^/stable/12
Basis des Projektarchivs: svn://svn.freebsd.org/base
UUID des Projektarchivs: ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Revision: 350885

uname -a: FreeBSD dssbkp1.incore 12.0-STABLE FreeBSD 12.0-STABLE r350885 SERVER64  amd64

On older Intel Hardware (SR2400 / SR2500) we are not able to boot from disk with kern.vty="vt" (boot disk includes software raid - gmirror+gjournal, no zfs).
Boot stalls immediately after starting the kernel (no matter if GENERIC or locally modified kernel is used).
In serial console log we see:

Booting [/boot/kernel/kernel]...
panic: pmap_mapdev_internal: too many preinit mappings
cpuid = 0
time = 1
KDB: stack backtrace:
Uptime: 1s

Booting with kern.vty="sc" works without any problem.
Booting from an installation CD, created by "make cdrom" in /usr/src/release of this version (r350885) works too (vt).
Booting this version on different hardware (HP DL360 G7) works as expected (same kernel version, gmirror+gjournal).

One of these non-running servers was already mentioned in bug #236838 including dmesg output.

Comment 1 bartsch 2019-09-11 07:33:25 UTC

At last we found the culprit.
There was a tunable set in loader.conf:
debug.late_console="0"
which caused this erroneuous behavior.

After removing this line from loader.conf, the servers boot as expected with kern.vty unset.

This PR can be closed.