2.1.109 writes beyond mem=64m limit

Jean Meloche (jean@stat.ubc.ca)
Sun, 19 Jul 1998 07:27:55 -0800

I got 2.1.109ac2 running on a dual ppro.
I always boot with mem=64m.
I have in fact 128mb of ram.

After the boot has completed, I access the memory not used
by the kernel with

base=len=64*1024*1024;
ioremap(base,len);

To my surprise, I find that something has been writing past
the supplied imposed mem=64m limit (starting at base=64*1024*1024):

00000000: 02 00 00 00 55 aa a5 5a 55 aa a5 5a ff ff ff ff
....U..ZU..Z....
00000010: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
................
00000020: 00 00 00 00 ff ff ff ff ff ff ff ff ff ff ff ff
................
...
000007d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
................
000007e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
................
000007f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
................
00000800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
................
00000810: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
................
00000820: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
................
...
00000fd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
................
00000fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
................
00000ff0: 00 00 00 00 00 00 53 57 41 50 2d 53 50 41 43 45
......SWAP-SPACE
00001000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
................
00001010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
................


How is that possible?

-- 


Jean Meloche


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