perfcounters: fix refcounting bug, take 2

Only free child_counter if it has a parent; if it doesn't, then it
has a file pointing to it and we'll free it in perf_release.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 4 insertions, 5 deletions

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index e0576c3fdb50..fcefb0a726f3 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -1958,14 +1958,13 @@ __perf_counter_exit_task(struct task_struct *child,
                 sync_child_counter(child_counter, parent_counter);
                 list_for_each_entry_safe(sub, tmp, &child_counter->sibling_list,
                                          list_entry) {
-                        if (sub->parent)
+                        if (sub->parent) {
                                 sync_child_counter(sub, sub->parent);
-                        kfree(sub);
+                                kfree(sub);
+                        }
                 }
-        }
-
-        if (!child_counter->filp || !atomic_long_read(&child_counter->filp->f_count))
                 kfree(child_counter);
+        }
 }
 
 /*