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SubjectRe: Linux 2.4.11-pre4
> 1. OK, it fixes the UP UP_IOAPIC compilation problem.
> System (with preempt-patch) up and runnig.

Good.

> 2. Woohu. I have 8 CPUs, now...;-)
> --- /proc is somewhat broken

Bugger. Didn't realise that cpu_online_map didn't get initialised
to anything sensible under UP. Should be just cosmetic (it's only
the output of /proc/cpuinfo, not the sceduler or anything), but
try this (I haven't tested it yet - if it doesn't work, just change the
8 to 1 for a second whilst I fix it properly).

===========================

--- setup.c.old Fri Oct 5 14:20:29 2001
+++ setup.c Fri Oct 5 14:28:51 2001
@@ -2420,7 +2420,7 @@
* WARNING - nasty evil hack ... if we print > 8, it overflows the
* page buffer and corrupts memory - this needs fixing properly
*/
- for (n = 0; n < 8; n++, c++) {
+ for (n = 0; n < (clustered_apic_mode ? 8 : NR_CPUS); n++, c++) {
/* for (n = 0; n < NR_CPUS; n++, c++) { */
int fpu_exception;
#ifdef CONFIG_SMP
===========================
The reason for this hackery is that get_cpuinfo writes to a page
without proper bounds on itself. If you have more than about 8
cpus, it tramples merrily all over the next page, corrupting page
tables, etc, etc.

The real fix for this overflow was published here a few weeks ago
by James Cleverdon (whom I work with). It's in Alan's tree, but not
Linus' as yet.

M.

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