x86/hwmon: avoid deadlock on CPU removal in pkgtemp

pkgtemp_device_remove(), holding the list protecting mutex, calls
pkgtemp_device_add(), which itself wants to acquire the same mutex.
Holding the mutex over the entire loop body in pkgtemp_device_remove()
isn't really necessary, as long as the loop gets exited after
processing the matched CPU.

Once exiting the loop after removing an eventual match, there's no
need for using the "safe" list iterator anymore.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NGuenter Roeck <guenter.roeck@ericsson.com>

drivers/hwmon/pkgtemp.c

@@ -339,17 +339,18 @@ static int __cpuinit pkgtemp_device_add(unsigned int cpu)
 #ifdef CONFIG_HOTPLUG_CPU
 static void pkgtemp_device_remove(unsigned int cpu)
 {
-	struct pdev_entry *p, *n;
+	struct pdev_entry *p;
 	unsigned int i;
 	int err;
 
 	mutex_lock(&pdev_list_mutex);
-	list_for_each_entry_safe(p, n, &pdev_list, list) {
+	list_for_each_entry(p, &pdev_list, list) {
 		if (p->cpu != cpu)
 			continue;
 
 		platform_device_unregister(p->pdev);
 		list_del(&p->list);
+		mutex_unlock(&pdev_list_mutex);
 		kfree(p);
 		for_each_cpu(i, cpu_core_mask(cpu)) {
 			if (i != cpu) {
@@ -358,7 +359,7 @@ static void pkgtemp_device_remove(unsigned int cpu)
 					break;
 			}
 		}
-		break;
+		return;
 	}
 	mutex_unlock(&pdev_list_mutex);
 }