From d52c0569bab4edc888832df44dc7ac28517134f6 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Thu, 11 Aug 2016 16:08:35 +0200 Subject: [PATCH] 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: Laura Abbott Signed-off-by: Sebastian Andrzej Siewior Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: 6b2c28471de5 ("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: Ingo Molnar --- arch/x86/kernel/apic/x2apic_cluster.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/apic/x2apic_cluster.c b/arch/x86/kernel/apic/x2apic_cluster.c index 6368fa69d2af..54f35d988025 100644 --- a/arch/x86/kernel/apic/x2apic_cluster.c +++ b/arch/x86/kernel/apic/x2apic_cluster.c @@ -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; + 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)); - cpuhp_setup_state(CPUHP_X2APIC_PREPARE, "X2APIC_PREPARE", - x2apic_prepare_cpu, x2apic_dead_cpu); return 1; } -- 2.20.1