misc/127917: [patch] dumpon rejects on start with physmem>swap even with minidump=1

[pluknet]

>Number:         127917
>Category:       misc
>Synopsis:       [patch] dumpon rejects on start with physmem>swap even with minidump=1
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Oct 07 12:20:02 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator:     pluknet
>Release:        6.2-R
>Organization:
RIPN
>Environment:
FreeBSD jaw.ripn.net 6.2-RELEASE-p12 FreeBSD 6.2-RELEASE-p12 #86: Tue Oct  7 15:43:58 MSD 2008     root at jaw.ripn.net:/usr/obj/usr/src/sys/JAW  i386
>Description:
Minidump feature allows to dump kcore even with physical memory less than size of a swap device.

$ sysctl debug.minidump=0
debug.minidump: 1 -> 0
$ /etc/rc.d/dumpon start
/dev/ad0s1b is smaller than physical memory
$ sysctl debug.minidump=1
debug.minidump: 0 -> 1
$ /etc/rc.d/dumpon start
kernel dumps on /dev/ad0s1b

All right. But it does not always work on boot (of course,
with properly set debug.minidump=1 in /etc/sysctl.conf)
and we have on boot:
/dev/ad0s1b is smaller than physical memory.

>How-To-Repeat:
Get a lesser swap slice then phys memory size.
Set sysctl debug.minidump=1 in /etc/sysctl.conf
Place dumpdev="/dev/ad0s1b" (according to your setup) in /etc/rc.conf
Reboot.
>Fix:
 That's because /etc/rc.d/dumpon starts before /etc/rc.d/sysctl.
To be fixed.
-----------
--- /etc/rc.d/dumpon.orig       Tue Oct  7 16:09:52 2008
+++ /etc/rc.d/dumpon    Tue Oct  7 15:49:42 2008
@@ -5,6 +5,7 @@
 
 # PROVIDE: dumpon
 # BEFORE: disks savecore initrandom
+# REQUIRE: sysctl
 # KEYWORD: nojail
 
 . /etc/rc.subr
-----------

After fix (dmesg -a):
---
/dev/ad0s1d: clean, 417342 free (694 frags, 52081 blocks, 0.1% fragmentation)
net.inet6.ip6.auto_linklocal: 
1
 -> 
0

hw.syscons.bell: 
1
 -> 
0

debug.minidump: 
0
 -> 
1

kernel dumps on /dev/ad0s1b
Entropy harvesting:
---

>Release-Note:
>Audit-Trail:
>Unformatted: