Subject: Problems with `mmap'
To: None <,>
From: Johan Rydberg <>
List: tech-kern
Date: 04/03/2000 15:37:28

I have run into some problems with mmap on /dev/kmem (we're
running NetBSD-1.4.1/arm32). 

Description of the problem;

A user level applications retreives a kernel address, maps
it into its address space with `mmap' (write-able).   It then
modifies some of the data and does a `ioctrl' into our driver
that checks the data. Sometimes the data is beeing modifies
when switching from user to kernel address space. It seems
that the data is put on the free list or something . If you
examin the data, it has the following pattern;

0       4        8        12
ADDRESS deadbeef deadbeef deadbeef ...

This never happens when we run on NetBSD-1.4.1/i386.

Any ideas what can be the problem ?

Johan Rydberg
Net Insight AB, Sweden		direct: +46-8-685 04 17	phone:  +46-8-685 04 00
				fax:    +46-8-685 04 20