Commit d9bca435 authored Sep 13, 2010 by Jan Beulich Committed by Guenter Roeck Sep 24, 2010

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: Jan Beulich <jbeulich@novell.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>

parent 89a3fd35

drivers/hwmon/pkgtemp.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -339,17 +339,18 @@ exit:
		#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);
		}

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