Re: i386 cpu hotplug bug - instant reboot when onlining secondary

[Nathan Lynch <ntl@pobox.com>]

Zwane Mwaikambo wrote:
> On Tue, 28 Feb 2006, Nathan Lynch wrote:
> 
> > 
> > [17179687.244000] CPU 1 is now offline
> > [17179693.164000] Booting processor 1/1 eip 3000
> > [17179693.216000] CPU 1 irqstacks, hard=7837f000 soft=78377000
> > [17179693.284000] Setting warm reset code and vector.
> > [17179693.340000] 1.
> > [17179693.364000] 2.
> > [17179693.388000] 3.
> > [17179693.408000] Asserting INIT.
> > [17179693.448000] Waiting for send to finish...
> > [17179693.496000] +<7>Deasserting INIT.
> > [17179693.552000] Waiting for send to finish...
> > [17179693.600000] +<7>#startup loops: 2.
> > [17179693.644000] Sending STARTUP #1.
> > [17179693.688000] After apic_write.
> > [17179693.724000] Doing apic_write_around for target chip...
> > [17179693.788000] Doing apic_write_around to kick the second...
> 
> Ok, could you apply only the following patch?

Sorry for the delay in getting back to you.

Applied your latest patch, (plus one-liner to make Dprintk actually
print) -- I don't see any of the new print statements:

[17179687.744000] CPU 1 is now offline
[17179693.032000] Booting processor 1/1 eip 3000
[17179693.084000] CPU 1 irqstacks, hard=783da000 soft=783d2000
[17179693.152000] Setting warm reset code and vector.
[17179693.208000] 1.
[17179693.232000] 2.
[17179693.256000] 3.
[17179693.276000] Asserting INIT.
[17179693.316000] Waiting for send to finish...
[17179693.364000] +<7>Deasserting INIT.
[17179693.420000] Waiting for send to finish...
[17179693.468000] +<7>#startup loops: 2.
[17179693.512000] Sending STARTUP #1.
[17179693.556000] After apic_write.



> 
> Index: linux-2.6.16-rc2-mm1/arch/i386/kernel/smpboot.c
> ===================================================================
> RCS file: /home/cvsroot/linux-2.6.16-rc2-mm1/arch/i386/kernel/smpboot.c,v
> retrieving revision 1.1.1.1
> diff -u -p -B -r1.1.1.1 smpboot.c
> --- linux-2.6.16-rc2-mm1/arch/i386/kernel/smpboot.c	11 Feb 2006 16:55:14 -0000	1.1.1.1
> +++ linux-2.6.16-rc2-mm1/arch/i386/kernel/smpboot.c	1 Mar 2006 06:30:06 -0000
> @@ -535,9 +535,14 @@ static void __devinit start_secondary(vo
>  	 * booting is too fragile that we want to limit the
>  	 * things done here to the most necessary things.
>  	 */
> +	Dprintk("S1\n");
>  	cpu_init();
> +	Dprintk("S2\n");
>  	preempt_disable();
> +	Dprintk("S3\n");
>  	smp_callin();
> +	Dprintk("S4\n");
> +
>  	while (!cpu_isset(smp_processor_id(), smp_commenced_mask))
>  		rep_nop();
>  	setup_secondary_APIC_clock();