1 files changed, 16 insertions, 8 deletions

diff --git a/arch/x86/oprofile/op_model_amd.c b/arch/x86/oprofile/op_model_amd.c
index a011bcc0f94..7d90d47655b 100644
--- a/arch/x86/oprofile/op_model_amd.c
+++ b/arch/x86/oprofile/op_model_amd.c
@@ -630,21 +630,29 @@ static int __init_ibs_nmi(void)
         return 0;
 }
 
-/* initialize the APIC for the IBS interrupts if available */
+/*
+ * check and reserve APIC extended interrupt LVT offset for IBS if
+ * available
+ *
+ * init_ibs() preforms implicitly cpu-local operations, so pin this
+ * thread to its current CPU
+ */
+
 static void init_ibs(void)
 {
-        ibs_caps = get_ibs_caps();
+        preempt_disable();
 
+        ibs_caps = get_ibs_caps();
         if (!ibs_caps)
-                return;
+                goto out;
 
-        if (__init_ibs_nmi()) {
+        if (__init_ibs_nmi() < 0)
                 ibs_caps = 0;
-                return;
-        }
+        else
+                printk(KERN_INFO "oprofile: AMD IBS detected (0x%08x)\n", ibs_caps);
 
-        printk(KERN_INFO "oprofile: AMD IBS detected (0x%08x)\n",
-               (unsigned)ibs_caps);
+out:
+        preempt_enable();
 }
 
 static int (*create_arch_files)(struct super_block *sb, struct dentry *root);