On Thu, Apr 01, 1999 at 05:22:45PM +0200, Manuel Bouyer wrote:
> On Apr 1, Thor Lancelot Simon wrote
> > No, it's not.  I can't reproduce it any more (dammit) but I was getting it
> > regularly about a week ago.  I have a machine with a large FFS filesystem I
> > burn ISO9660 disks from.  Running mkhybrid would cause a pmap_zero_page panic
> > when the mkhybrid program exited, unless I typed "sync" after it did its last
> > disk write but before it had printed its final messages and exited.
> > 
> > As soon as I tried to track it down the problem went away -- but I definitely
> > saw it.  This was on hardware which had been 100% reliable for several months.
> 
> 
> Hoooo, this is becomming interesting :).
> I'll try a kernel from today (with the resent VM and pool changes) and see
> how it gets.
> 
> What hardware does your machine have ? IDE or SCSI disks. How many
> disk buffer cache ?

Cyrix 6x86 (non-MMX) 120MHz, Intel TX-chipset motherboard, 32MB 66MHz SDRAM.

3Com 3c905B with "ex" driver, and a single Seagate Medallist 6.5GB UDMA IDE
disk.  A bunch of other stuff was running -- samba, lpd, xfs, etc.  Amusingly,
I thought the problem was LFS-related but actually the machine didn't have any
LFS filesystems mounted, I'd forgotten that I'd switched the samba volume back
to FFS before I started having problems.

I didn't tweak the buffer cache at all.

Of course, it was precisely when I went to try to write down a traceback that
I stopped being able to make the problem happen -- but as I recall the traces
I got before but didn't write down ran through the vnode pager (which kind of
makes sense, since the problem was happening when the program exited, not
while it was writing data).