Linux 2.4.17 bug, mmap of /dev/mem

[Goddeeris Frederic]

Hi David,

I tested your application on my board (Embedded Planet CLLF (mpc860), Linux
2.4.2) and made a script that executes it as fast as possible.
I let it run for 10 minutes on several telnet sessions simultaneously but I
do not see anything strange... The memory I write to is NVRAM.

Frederic

-----Original Message-----
From: David Ashley
To: linuxppc-embedded at lists.linuxppc.org
Sent: 2/12/02 1:36 AM
Subject: Re: Linux 2.4.17 bug, mmap of /dev/mem


I found out more about the problem. If I mmap 2 regions that are
distinct,
even though they map to the same physical address in non-cacheable
memory,
if I only use one for reading and the other for writing, there is no
corruption of linux and the system works. The problem happens when I
both
read and write to the same mmap'd area.

Easy enough workaround. Now maybe some kernel expert can figure it
out???????

Later--
Dave


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