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Date: Sun, 12 Feb 2006 14:04:36 -0800 (PST)
From: Zwane Mwaikambo <zwane@arm.linux.org.uk>
To: Linux Kernel <linux-kernel@vger.kernel.org>
cc: Andrew Morton <akpm@osdl.org>, Nathan Lynch <nathanl@austin.ibm.com>,
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tsc_disable was marked __initdata so we were accessing random data (which 
happened to have a set bit) so upon warm cpu online we would disable the 
TSC, resulting in the following. Nathan does this fix your triple fault?

root@arusha cpu1 {0:0} echo 1 > online
Booting processor 1/1 eip 3000
Disabling TSC...
Calibrating delay using timer specific routine.. 797.62 BogoMIPS 
(lpj=3988115)
CPU1: Intel Pentium II (Deschutes) stepping 02
migration_cost=2595
root@arusha cpu1 {0:0} ps
  PID TTY          TIME CMD
 2432 ttyS0    00:00:00 tcsh
 2490 ttyS0    00:00:00 ps
root@arusha cpu1 {0:0} ps
Segmentation fault
root@arusha cpu1 {0:139}

<signed-off-by> Zwane Mwaikambo <zwane@arm.linux.org.uk>

Index: linux-2.6.16-rc2-mm1/arch/i386/kernel/tsc.c
===================================================================
RCS file: /home/cvsroot/linux-2.6.16-rc2-mm1/arch/i386/kernel/tsc.c,v
retrieving revision 1.1.1.1
diff -u -p -B -r1.1.1.1 tsc.c
--- linux-2.6.16-rc2-mm1/arch/i386/kernel/tsc.c	11 Feb 2006 16:55:15 -0000	1.1.1.1
+++ linux-2.6.16-rc2-mm1/arch/i386/kernel/tsc.c	12 Feb 2006 22:00:12 -0000
@@ -25,7 +25,7 @@
  */
 unsigned int tsc_khz;
 
-int tsc_disable __initdata = 0;
+int tsc_disable __cpuinitdata = 0;
 
 #ifdef CONFIG_X86_TSC
 static int __init tsc_setup(char *str)
-
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