Commit 7496b606 authored May 12, 2008 by Mike Travis Committed by Ingo Molnar Jul 08, 2008

x86: fix remove cpu_pda table patch

Mike Travis wrote:
> Ingo Molnar wrote:
>> * Mike Travis <travis@sgi.com> wrote:
>>
>>> [Ingo - please replace "PATCH 07/11" with this one.]
>>>
>>>     *	Remove 544k bytes from the kernel by removing the boot_cpu_pda
>>> 	array from the data section and allocating it during startup.
>>>
>>> 	Fixed panic in setup_per_cpu_areas when HOTPLUG_CPU not set.
>>>
>>> For inclusion into sched-devel/latest tree.
>> sched-devel.git randconfig testing found another crash with your queue:
>>
>> [    0.111060] Brought up 1 CPUs
>> [    0.111986] Total of 1 processors activated (4022.73 BogoMIPS).
>> [    0.112987] Testing NMI watchdog ... <1>BUG: unable to handle kernel NULL pointer dereference at 0000000000000040
>> [    0.114982] IP: [<ffffffff8180d4a0>] check_nmi_watchdog+0xb0/0x210
>> [    0.114982] PGD 0
>> [    0.114982] Oops: 0000 [1] SMP
>> [    0.114982] CPU 0
>> [............]
>>
>>  http://redhat.com/~mingo/misc/config-Mon_Apr_28_23_25_25_CEST_2008.bad
>>  http://redhat.com/~mingo/misc/log-Mon_Apr_28_23_25_25_CEST_2008.bad
>>
>> 	Ingo
>
> Hi Ingo,
>
> I need a bit more information on your hardware configuration.  Building a
> kernel with the above config file started up fine on both the Intel and AMD
> boxes.
>
> Based on the above output it looks like it might be a UP machine?
...

Ok, I think I found it.  In check_nmi_watchdog():

        for (cpu = 0; cpu < NR_CPUS; cpu++)
                prev_nmi_count[cpu] = cpu_pda(cpu)->__nmi_count;

As I mentioned it works fine on both of my systems so could you try it out?

Thanks!
Mike
--

  * Change function check_nmi_watchdog() to use nr_cpu_ids instead of NR_CPUS.

Based on:
	git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git


    +   sched-devel/latest  .../mingo/linux-2.6-sched-devel.git

Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent dbb6152e

arch/x86/kernel/nmi_64.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -88,7 +88,7 @@ int __init check_nmi_watchdog(void)
		if (!atomic_read(&nmi_active))
		return 0;

		prev_nmi_count = kmalloc(NR_CPUS * sizeof(int), GFP_KERNEL);
		prev_nmi_count = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
		if (!prev_nmi_count)
		return -1;

		@@ -99,7 +99,7 @@ int __init check_nmi_watchdog(void)
		smp_call_function(nmi_cpu_busy, (void *)&endflag, 0, 0);
		#endif

		for (cpu = 0; cpu < NR_CPUS; cpu++)
		for (cpu = 0; cpu < nr_cpu_ids; cpu++)
		prev_nmi_count[cpu] = cpu_pda(cpu)->__nmi_count;
		local_irq_enable();
		mdelay((20*1000)/nmi_hz); // wait 20 ticks

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