1 files changed, 15 insertions, 8 deletions

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 574ee58a3046..2f3fbf84215a 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -15,6 +15,7 @@
 #include <linux/smp.h>
 #include <linux/file.h>
 #include <linux/poll.h>
+#include <linux/slab.h>
 #include <linux/sysfs.h>
 #include <linux/dcache.h>
 #include <linux/percpu.h>
@@ -1164,11 +1165,9 @@ void perf_event_task_sched_out(struct task_struct *task,
         struct perf_event_context *ctx = task->perf_event_ctxp;
         struct perf_event_context *next_ctx;
         struct perf_event_context *parent;
-        struct pt_regs *regs;
         int do_switch = 1;
 
-        regs = task_pt_regs(task);
-        perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, regs, 0);
+        perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);
 
         if (likely(!ctx || !cpuctx->task_ctx))
                 return;
@@ -2786,12 +2785,11 @@ __weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
         return NULL;
 }
 
-#ifdef CONFIG_EVENT_TRACING
 __weak
 void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip)
 {
 }
-#endif
+
 
 /*
  * Output
@@ -3378,15 +3376,23 @@ static void perf_event_task_output(struct perf_event *event,
                                      struct perf_task_event *task_event)
 {
         struct perf_output_handle handle;
-        int size;
         struct task_struct *task = task_event->task;
-        int ret;
+        unsigned long flags;
+        int size, ret;
+
+        /*
+         * If this CPU attempts to acquire an rq lock held by a CPU spinning
+         * in perf_output_lock() from interrupt context, it's game over.
+         */
+        local_irq_save(flags);
 
         size  = task_event->event_id.header.size;
         ret = perf_output_begin(&handle, event, size, 0, 0);
 
-        if (ret)
+        if (ret) {
+                local_irq_restore(flags);
                 return;
+        }
 
         task_event->event_id.pid = perf_event_pid(event, task);
         task_event->event_id.ppid = perf_event_pid(event, current);
@@ -3397,6 +3403,7 @@ static void perf_event_task_output(struct perf_event *event,
         perf_output_put(&handle, task_event->event_id);
 
         perf_output_end(&handle);
+        local_irq_restore(flags);
 }
 
 static int perf_event_task_match(struct perf_event *event)