3 files changed, 29 insertions, 9 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 2ebfc9ae4755..97965fac55fe 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -536,6 +536,12 @@ struct hw_perf_event {
                 struct { /* breakpoint */
                         struct arch_hw_breakpoint       info;
                         struct list_head                bp_list;
+                        /*
+                         * Crufty hack to avoid the chicken and egg
+                         * problem hw_breakpoint has with context
+                         * creation and event initalization.
+                         */
+                        struct task_struct              *bp_target;
                 };
 #endif
         };
@@ -693,6 +699,7 @@ struct swevent_hlist {
 
 #define PERF_ATTACH_CONTEXT     0x01
 #define PERF_ATTACH_GROUP       0x02
+#define PERF_ATTACH_TASK        0x04
 
 /**
  * struct perf_event - performance event kernel representation:
diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c
index 3b714e839c10..2c9120f0afca 100644
--- a/kernel/hw_breakpoint.c
+++ b/kernel/hw_breakpoint.c
@@ -113,12 +113,12 @@ static unsigned int max_task_bp_pinned(int cpu, enum bp_type_idx type)
  */
 static int task_bp_pinned(struct perf_event *bp, enum bp_type_idx type)
 {
-        struct perf_event_context *ctx = bp->ctx;
+        struct task_struct *tsk = bp->hw.bp_target;
         struct perf_event *iter;
         int count = 0;
 
         list_for_each_entry(iter, &bp_task_head, hw.bp_list) {
-                if (iter->ctx == ctx && find_slot_idx(iter) == type)
+                if (iter->hw.bp_target == tsk && find_slot_idx(iter) == type)
                         count += hw_breakpoint_weight(iter);
         }
 
@@ -134,7 +134,7 @@ fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp,
                     enum bp_type_idx type)
 {
         int cpu = bp->cpu;
-        struct task_struct *tsk = bp->ctx->task;
+        struct task_struct *tsk = bp->hw.bp_target;
 
         if (cpu >= 0) {
                 slots->pinned = per_cpu(nr_cpu_bp_pinned[type], cpu);
@@ -213,7 +213,7 @@ toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type,
                int weight)
 {
         int cpu = bp->cpu;
-        struct task_struct *tsk = bp->ctx->task;
+        struct task_struct *tsk = bp->hw.bp_target;
 
         /* Pinned counter cpu profiling */
         if (!tsk) {
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index b21d06aaef60..856e20baf13f 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -5255,9 +5255,10 @@ unlock:
  */
 static struct perf_event *
 perf_event_alloc(struct perf_event_attr *attr, int cpu,
-                   struct perf_event *group_leader,
-                   struct perf_event *parent_event,
-                   perf_overflow_handler_t overflow_handler)
+                 struct task_struct *task,
+                 struct perf_event *group_leader,
+                 struct perf_event *parent_event,
+                 perf_overflow_handler_t overflow_handler)
 {
         struct pmu *pmu;
         struct perf_event *event;
@@ -5299,6 +5300,17 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
 
         event->state            = PERF_EVENT_STATE_INACTIVE;
 
+        if (task) {
+                event->attach_state = PERF_ATTACH_TASK;
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+                /*
+                 * hw_breakpoint is a bit difficult here..
+                 */
+                if (attr->type == PERF_TYPE_BREAKPOINT)
+                        event->hw.bp_target = task;
+#endif
+        }
+
         if (!overflow_handler && parent_event)
                 overflow_handler = parent_event->overflow_handler;
         
@@ -5559,7 +5571,7 @@ SYSCALL_DEFINE5(perf_event_open,
                 }
         }
 
-        event = perf_event_alloc(&attr, cpu, group_leader, NULL, NULL);
+        event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, NULL);
         if (IS_ERR(event)) {
                 err = PTR_ERR(event);
                 goto err_task;
@@ -5728,7 +5740,7 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
          * Get the target context (task or percpu):
          */
 
-        event = perf_event_alloc(attr, cpu, NULL, NULL, overflow_handler);
+        event = perf_event_alloc(attr, cpu, task, NULL, NULL, overflow_handler);
         if (IS_ERR(event)) {
                 err = PTR_ERR(event);
                 goto err;
@@ -5996,6 +6008,7 @@ inherit_event(struct perf_event *parent_event,
 
         child_event = perf_event_alloc(&parent_event->attr,
                                            parent_event->cpu,
+                                           child,
                                            group_leader, parent_event,
                                            NULL);
         if (IS_ERR(child_event))