Re: [PATCH] Fix CPU hotplug with new time infrastructure

From: Nathan Lynch
Date: Sun Feb 12 2006 - 21:48:06 EST


Zwane Mwaikambo wrote:
> 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?

Doesn't apply to latest -linus, which is where I've been seeing that.
I found tsc_disable in arch/i386/kernel/timers/timer_tsc.c, but it's
marked __devinitdata.

So my problem would appear to be something different; I'll try to get
more information, thanks.


> 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@xxxxxxxxxxxxxxxx>
>
> 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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