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Commit d52c0569 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Ingo Molnar
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x86/apic/x2apic, smp/hotplug: Don't use before alloc in x2apic_cluster_probe() 



I made a mistake while converting the driver to the hotplug state
machine and as a result x2apic_cluster_probe() was accessing
cpus_in_cluster before allocating it.

This patch fixes it by setting the cpumask after the allocation the
memory succeeded.

While at it, I marked two functions static which are only used within
this file.

Reported-by: default avatarLaura Abbott <labbott@redhat.com>
Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 6b2c2847 ("x86/x2apic: Convert to CPU hotplug state machine")
Link: http://lkml.kernel.org/r/1470924515-9444-1-git-send-email-bigeasy@linutronix.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 5bc653b7

arch/x86/kernel/apic/x2apic_cluster.c

+9 −4
Original line number Diff line number Diff line
@@ -155,7 +155,7 @@ static void init_x2apic_ldr(void) 
/*

 * At CPU state changes, update the x2apic cluster sibling info.

 */

int x2apic_prepare_cpu(unsigned int cpu)

static int x2apic_prepare_cpu(unsigned int cpu)

{

	if (!zalloc_cpumask_var(&per_cpu(cpus_in_cluster, cpu), GFP_KERNEL))

		return -ENOMEM;
@@ -168,7 +168,7 @@ int x2apic_prepare_cpu(unsigned int cpu) 
	return 0;

}



int x2apic_dead_cpu(unsigned int this_cpu)

static int x2apic_dead_cpu(unsigned int this_cpu)

{

	int cpu;
@@ -186,13 +186,18 @@ int x2apic_dead_cpu(unsigned int this_cpu) 
static int x2apic_cluster_probe(void)

{

	int cpu = smp_processor_id();

	int ret;



	if (!x2apic_mode)

		return 0;



	cpumask_set_cpu(cpu, per_cpu(cpus_in_cluster, cpu));

	cpuhp_setup_state(CPUHP_X2APIC_PREPARE, "X2APIC_PREPARE",

	ret = cpuhp_setup_state(CPUHP_X2APIC_PREPARE, "X2APIC_PREPARE",

				x2apic_prepare_cpu, x2apic_dead_cpu);

	if (ret < 0) {

		pr_err("Failed to register X2APIC_PREPARE\n");

		return 0;

	}

	cpumask_set_cpu(cpu, per_cpu(cpus_in_cluster, cpu));

	return 1;

}