1 files changed, 12 insertions, 4 deletions

diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c
index 1f3abe048e93..a153b3905f60 100644
--- a/arch/x86/kernel/msr.c
+++ b/arch/x86/kernel/msr.c
@@ -117,12 +117,20 @@ static int msr_open(struct inode *inode, struct file *file)
 {
         unsigned int cpu = iminor(file->f_path.dentry->d_inode);
         struct cpuinfo_x86 *c = &cpu_data(cpu);
+        int ret = 0;
 
-        if (cpu >= NR_CPUS || !cpu_online(cpu))
-                return -ENXIO;  /* No such CPU */
-        if (!cpu_has(c, X86_FEATURE_MSR))
-                return -EIO;    /* MSR not supported */
+        lock_kernel();
+        cpu = iminor(file->f_path.dentry->d_inode);
 
+        if (cpu >= NR_CPUS || !cpu_online(cpu)) {
+                ret = -ENXIO;   /* No such CPU */
+                goto out;
+        }
+        c = &cpu_data(cpu);
+        if (!cpu_has(c, X86_FEATURE_MSR))
+                ret = -EIO;     /* MSR not supported */
+out:
+        unlock_kernel();
         return 0;
 }