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Commit 05bbb936 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull perf fixes from Thomas Gleixner:
 "Two small fixes for kprobes and perf:

   - Prevent a deadlock in kprobe_optimizer() causes by reverse lock
     ordering

   - Fix a comment typo"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  kprobes: Fix potential deadlock in kprobe_optimizer()
  perf/x86: Fix typo in comment
parents 44c471e4 f1c6ece2

arch/x86/events/core.c

+1 −1
Original line number Diff line number Diff line
@@ -1236,7 +1236,7 @@ void x86_pmu_enable_event(struct perf_event *event) 
 * Add a single event to the PMU.

 *

 * The event is added to the group of enabled events

 * but only if it can be scehduled with existing events.

 * but only if it can be scheduled with existing events.

 */

static int x86_pmu_add(struct perf_event *event, int flags)

{

kernel/kprobes.c

+4 −4
Original line number Diff line number Diff line
@@ -470,6 +470,7 @@ static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer); 
 */

static void do_optimize_kprobes(void)

{

	lockdep_assert_held(&text_mutex);

	/*

	 * The optimization/unoptimization refers online_cpus via

	 * stop_machine() and cpu-hotplug modifies online_cpus.
@@ -487,9 +488,7 @@ static void do_optimize_kprobes(void) 
	    list_empty(&optimizing_list))

		return;



	mutex_lock(&text_mutex);

	arch_optimize_kprobes(&optimizing_list);

	mutex_unlock(&text_mutex);

}



/*
@@ -500,6 +499,7 @@ static void do_unoptimize_kprobes(void) 
{

	struct optimized_kprobe *op, *tmp;



	lockdep_assert_held(&text_mutex);

	/* See comment in do_optimize_kprobes() */

	lockdep_assert_cpus_held();
@@ -507,7 +507,6 @@ static void do_unoptimize_kprobes(void) 
	if (list_empty(&unoptimizing_list))

		return;



	mutex_lock(&text_mutex);

	arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list);

	/* Loop free_list for disarming */

	list_for_each_entry_safe(op, tmp, &freeing_list, list) {
@@ -524,7 +523,6 @@ static void do_unoptimize_kprobes(void) 
		} else

			list_del_init(&op->list);

	}

	mutex_unlock(&text_mutex);

}



/* Reclaim all kprobes on the free_list */
@@ -556,6 +554,7 @@ static void kprobe_optimizer(struct work_struct *work) 
{

	mutex_lock(&kprobe_mutex);

	cpus_read_lock();

	mutex_lock(&text_mutex);

	/* Lock modules while optimizing kprobes */

	mutex_lock(&module_mutex);
@@ -583,6 +582,7 @@ static void kprobe_optimizer(struct work_struct *work) 
	do_free_cleaned_kprobes();



	mutex_unlock(&module_mutex);

	mutex_unlock(&text_mutex);

	cpus_read_unlock();

	mutex_unlock(&kprobe_mutex);