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

Pull perf fixes from Thomas Gleixner:
 "Four patches which all address lock inversions and deadlocks in the
  perf core code and the Intel debug store"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86: Fix perf,x86,cpuhp deadlock
  perf/core: Fix ctx::mutex deadlock
  perf/core: Fix another perf,trace,cpuhp lock inversion
  perf/core: Fix lock inversion between perf,trace,cpuhp

1 files changed, 18 insertions, 15 deletions

diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 8156e47da7ba..18c25ab28557 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -372,10 +372,9 @@ static int alloc_pebs_buffer(int cpu)
 static void release_pebs_buffer(int cpu)
 {
 	struct cpu_hw_events *hwev = per_cpu_ptr(&cpu_hw_events, cpu);
-	struct debug_store *ds = hwev->ds;
 	void *cea;
 
-	if (!ds || !x86_pmu.pebs)
+	if (!x86_pmu.pebs)
 		return;
 
 	kfree(per_cpu(insn_buffer, cpu));
@@ -384,7 +383,6 @@ static void release_pebs_buffer(int cpu)
 	/* Clear the fixmap */
 	cea = &get_cpu_entry_area(cpu)->cpu_debug_buffers.pebs_buffer;
 	ds_clear_cea(cea, x86_pmu.pebs_buffer_size);
-	ds->pebs_buffer_base = 0;
 	dsfree_pages(hwev->ds_pebs_vaddr, x86_pmu.pebs_buffer_size);
 	hwev->ds_pebs_vaddr = NULL;
 }
@@ -419,16 +417,14 @@ static int alloc_bts_buffer(int cpu)
 static void release_bts_buffer(int cpu)
 {
 	struct cpu_hw_events *hwev = per_cpu_ptr(&cpu_hw_events, cpu);
-	struct debug_store *ds = hwev->ds;
 	void *cea;
 
-	if (!ds || !x86_pmu.bts)
+	if (!x86_pmu.bts)
 		return;
 
 	/* Clear the fixmap */
 	cea = &get_cpu_entry_area(cpu)->cpu_debug_buffers.bts_buffer;
 	ds_clear_cea(cea, BTS_BUFFER_SIZE);
-	ds->bts_buffer_base = 0;
 	dsfree_pages(hwev->ds_bts_vaddr, BTS_BUFFER_SIZE);
 	hwev->ds_bts_vaddr = NULL;
 }
@@ -454,16 +450,22 @@ void release_ds_buffers(void)
 	if (!x86_pmu.bts && !x86_pmu.pebs)
 		return;
 
-	get_online_cpus();
-	for_each_online_cpu(cpu)
+	for_each_possible_cpu(cpu)
+		release_ds_buffer(cpu);
+
+	for_each_possible_cpu(cpu) {
+		/*
+		 * Again, ignore errors from offline CPUs, they will no longer
+		 * observe cpu_hw_events.ds and not program the DS_AREA when
+		 * they come up.
+		 */
 		fini_debug_store_on_cpu(cpu);
+	}
 
 	for_each_possible_cpu(cpu) {
 		release_pebs_buffer(cpu);
 		release_bts_buffer(cpu);
-		release_ds_buffer(cpu);
 	}
-	put_online_cpus();
 }
 
 void reserve_ds_buffers(void)
@@ -483,8 +485,6 @@ void reserve_ds_buffers(void)
 	if (!x86_pmu.pebs)
 		pebs_err = 1;
 
-	get_online_cpus();
-
 	for_each_possible_cpu(cpu) {
 		if (alloc_ds_buffer(cpu)) {
 			bts_err = 1;
@@ -521,11 +521,14 @@ void reserve_ds_buffers(void)
 		if (x86_pmu.pebs && !pebs_err)
 			x86_pmu.pebs_active = 1;
 
-		for_each_online_cpu(cpu)
+		for_each_possible_cpu(cpu) {
+			/*
+			 * Ignores wrmsr_on_cpu() errors for offline CPUs they
+			 * will get this call through intel_pmu_cpu_starting().
+			 */
 			init_debug_store_on_cpu(cpu);
+		}
 	}
-
-	put_online_cpus();
 }
 
 /*