[GIT PULL] perf fixes

[Ingo Molnar]

Linus,

Please pull the latest perf-urgent-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 
perf-urgent-for-linus

   # HEAD: 059fcd8cd16622da6513804a7a3e826d152c6c96 perf/core: Plug potential 
memory leak in CPU_UP_PREPARE

A handful of CPU hotplug related fixes.

 Thanks,

        Ingo

------------------>
Thomas Gleixner (4):
      perf/x86/amd/uncore: Plug reference leak
      perf/core: Remove bogus UP_CANCELED hotplug state
      perf/core: Remove the bogus and dangerous CPU_DOWN_FAILED hotplug state
      perf/core: Plug potential memory leak in CPU_UP_PREPARE


 arch/x86/kernel/cpu/perf_event_amd_uncore.c | 2 ++
 kernel/events/core.c                        | 4 +---
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_amd_uncore.c 
b/arch/x86/kernel/cpu/perf_event_amd_uncore.c
index 49742746a6c9..8836fc9fa84b 100644
--- a/arch/x86/kernel/cpu/perf_event_amd_uncore.c
+++ b/arch/x86/kernel/cpu/perf_event_amd_uncore.c
@@ -323,6 +323,8 @@ static int amd_uncore_cpu_up_prepare(unsigned int cpu)
        return 0;
 
 fail:
+       if (amd_uncore_nb)
+               *per_cpu_ptr(amd_uncore_nb, cpu) = NULL;
        kfree(uncore_nb);
        return -ENOMEM;
 }
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 5946460b2425..0d58522103cd 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9206,7 +9206,7 @@ static void perf_event_init_cpu(int cpu)
        struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
 
        mutex_lock(&swhash->hlist_mutex);
-       if (swhash->hlist_refcount > 0) {
+       if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
                struct swevent_hlist *hlist;
 
                hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, 
cpu_to_node(cpu));
@@ -9282,11 +9282,9 @@ perf_cpu_notify(struct notifier_block *self, unsigned 
long action, void *hcpu)
        switch (action & ~CPU_TASKS_FROZEN) {
 
        case CPU_UP_PREPARE:
-       case CPU_DOWN_FAILED:
                perf_event_init_cpu(cpu);
                break;
 
-       case CPU_UP_CANCELED:
        case CPU_DOWN_PREPARE:
                perf_event_exit_cpu(cpu);
                break;