kern/53468: reproducible panic when MD /tmp partition fills up - FreeBSD 5.1-RELEASE

[Jamie Jones]

>Number:         53468
>Category:       kern
>Synopsis:       reproducible panic when MD /tmp partition fills up - FreeBSD 5.1-RELEASE
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Jun 18 15:00:30 PDT 2003
>Closed-Date:
>Last-Modified:
>Originator:     Jamie Jones <jamie at bishopston.net>
>Release:        FreeBSD 5.1-RELEASE i386
>Organization:
>Environment:
System: FreeBSD thompson.bishopston.net 5.1-RELEASE FreeBSD 5.1-RELEASE #5: Tue Jun 17 00:15:06 BST 2003 root at thompson.bishopston.net:/usr/obj/usr/src/sys/THOMPSON i386

malloc Memory Disk (MD_MALLOC) mounted on /tmp/ from /etc/fstab with
the following line:

md              /tmp            mfs     rw,nosuid,nodev,-M,-s=1000000   0       0

22:47 (75) "tmp" root at thompson# df -k /tmp
Filesystem 1K-blocks Used  Avail Capacity  Mounted on
/dev/md0      484110  678 444704     0%    /tmp

22:47 (76) "tmp" root at thompson# swapinfo 
Device          1K-blocks     Used    Avail Capacity  Type
/dev/ad0s3b        524288        0   524288     0%    Interleaved
/dev/ad1s1b        524288        0   524288     0%    Interleaved
Total             1048576        0  1048576     0%

22:47 (77) "jamie" jamie at thompson% sysctl hw.physmem hw.usermem
hw.physmem: 530747392
hw.usermem: 454123520

>Description:

Under certain conditions, filling up of the /tmp disk as mounted above
causes the system to panic. On certain conditions, the system doesn't
panic - instead it says "disk full". I'm not sure why it trips up some
times, but it's easily reproducable.

Panic message:

panic: kmem_malloc (4096) : kmem_map too small: 217788416 total allocated
Syncing disks, bufferes remaining... ad0: out of memory in start
ad0: out of memory in start
ad0: out of memory in start
ad0: out of memory in start
ad0: out of memory in start
..
..
..
Dumping 511MB
Dump failed. Partition too small

>How-To-Repeat:

22:54 (62) "tmp" jamie at thompson% cd /tmp

22:55 (63) "tmp" jamie at thompson% cat p
#!/bin/sh
while true
do
cat /COPYRIGHT
done

22:55 (64) "tmp" jamie at thompson% sh p > pp

then wait for partition to fill up..

>Fix:

unknown.

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