Subject: Re: Problems with postfix on NetBSD 4 RC1
To: Michael van Elst <>
From: Jan Danielsson <>
List: netbsd-users
Date: 09/16/2007 17:27:07
Hash: SHA512

Michael van Elst wrote:
>>    But this is actually pretty uninteresting. The *interesting* part is
>> that if I reboot, I'll probably be able to get the directory listing
>> when I've su:ed to pkgsrc and run "ls -l". Then, if I go out for a walk,
>> or if I use my normal user "jan" to startx, and browse around using
>> Firefox for a while, then "ls -l" with the su:ed pkgsrc user *won't* work.
> Ok. This is interesting and smells like a cache consistency problem.

   Hmm.. I would think that would pretty likely cause file system
corruptions? I haven't seen any such issues (Ugh.. That I know of...).

   IMHO, it feels like it fails when trying to enumerate
files/directories in a directory. It behaves just like if opendir(".")
returns a permission error in su:ed sessions. I could try to write an
application to test this theory. I can "cd" around, and run "pwd", and
"cat" files I know exist without any problems while the permission
problem is ruining my "ls" experience.

   This is fun:

- ----------------------------
$ whoami
$ pwd
$ user info pkgsrc
login   pkgsrc
passwd  *
uid     1001
groups  users
change  NEVER
dir     /home/pkgsrc
shell   /bin/ksh
expire  NEVER
$ ls -l
ls: .: Permission denied
$ ls -l u*
ls: u*: No such file or directory
$ cat update_pkgsrc
date > /var/log/pkgsrc.log
export CVS_RSH=ssh
cd ~/pkgsrc
/usr/bin/nice -n 20 /usr/bin/cvs update -APd >> /var/log/pkgsrc.log 2>&1
date >> /var/log/pkgsrc.log
$ mount
mount: getmntinfo: Permission denied
- ----------------------------

> I see that you don't use the GENERIC kernel. What did you change?

   I commented out lots of drivers to hardware I don't have. Apart from
commenting out SCSI controllers, ethernet controllers, USB stuff, I have
done the following changes (based on GENERIC):


options         CPURESET_DELAY=20000


# Enable the hooks used for initializing the root memory-disk.
options         MEMORY_DISK_HOOKS
options         MEMORY_DISK_IS_ROOT             # force root on memory disk
options         MEMORY_DISK_SERVER=0            # no userspace memory
disk support
options         MEMORY_DISK_ROOT_SIZE=6000      # size of memory disk,
in blocks
options         MEMORY_RBFLAGS=0                # do not force
single-user mode


options         SHMMAXPGS=65536 # 2048 pages is the default


options         POWERNOW_K8


#file-system    EXT2FS          # second extended file system (linux)


lm0     at isa? port 0x290              # other common ports: 0x280, 0x310


pseudo-device   cgd             8       # cryptographic disk devices


pseudo-device   pf                      # PF packet filter
pseudo-device   pflog                   # PF log if

   I may have missed something; but I'm pretty sure I haven't.

> Do you apply any tunings (sysctl)?

   My /etc/sysctl.conf contains:


   More importantly, my boot image uses the sysctl init.root to switch
from a root on a ramdisk to root cgd0a (on top of wd0a). (The use of
init.root is documented in the PR).

   Apart from that, no changes have been made with regards to sysctl.

> How much memory does your system have?

   2GB physical memory. I have no other instabilities, and the problems
occured when I switched to netbsd-4, so I doubt there's a hardware
problem (even though the flakyness of it suggests it is).

> The behaviour could be
> triggered by a memory shortage. Do you have swap configured?

   Yes, I have 1GB swap, but I almost never use up my 2GB RAM. (I have
never done so on NetBSD 4). The swap space is reported in "top", so I
assume that it's activated properly.

> What filesystem do you use? I wouldn't trust LFS for this,
> especially under low memory conditions.

   ffs on cgd.

- --
Kind regards,
Jan Danielsson

Version: GnuPG v1.4.7 (NetBSD)