Subject: kern/6641: mount_mfs can cause UVM crash
To: None <firstname.lastname@example.org>
From: Matthias Scheler <email@example.com>
Date: 12/24/1998 01:48:44
>Synopsis: mount_mfs can cause UVM crash
>Responsible: kern-bug-people (Kernel Bug People)
>Arrival-Date: Wed Dec 23 17:05:01 1998
>Originator: Matthias Scheler
Matthias Scheler http://home.owl.de/~tron/
System: NetBSD lyssa.owl.de 1.3I NetBSD 1.3I (LYSSA) #0: Wed Dec 23 11:36:07 MET 1998 firstname.lastname@example.org:/src/sys/compile/LYSSA i386
After replacing two 400MB swap partitions with a single 750MB one my system
started crashing while mounting a memory filesystem on "/tmp" somewhere
in the UVM code. Here's the output of DDB's trace command:
_amap_copy(fcffc204,fd0043fc,1,1,1e000) at _amap_copy+0x245
_uvm_fault(fcffc204,1e000,0,3,0) at _uvm_fault+0x163
_trap() at _trap+0x41b
The "fstab" looked like this:
/dev/sd0b none swap sw
/dev/sd0b /tmp mfs rw
By reducing the size of the memory filesystem to 512MB the problem can be
avoided completely. With a size between about 600 and 700MB the system
doesn't crash but "mount_mfs" hangs forever.
If it matters:
It's a Pentium II based system with 256MB main memory. 40% of the memory
are used for filesystem buffers.
Try to mount a memory filesystem on a swap partition with a size above 750MB.
Sorry, I don't know.