Merge tag 'trace-v4.11-rc5-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull ftrace fix from Steven Rostedt:
 "Namhyung Kim discovered a use after free bug. It has to do with adding
  a pid filter to function tracing in an instance, and then freeing the
  instance"

* tag 'trace-v4.11-rc5-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Fix function pid filter on instances

3 files changed, 12 insertions, 0 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 27bb2e61276e..dd3e91d68dc7 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5566,6 +5566,15 @@ static void clear_ftrace_pids(struct trace_array *tr)
         trace_free_pid_list(pid_list);
 }
 
+void ftrace_clear_pids(struct trace_array *tr)
+{
+        mutex_lock(&ftrace_lock);
+
+        clear_ftrace_pids(tr);
+
+        mutex_unlock(&ftrace_lock);
+}
+
 static void ftrace_pid_reset(struct trace_array *tr)
 {
         mutex_lock(&ftrace_lock);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f35109514a01..d484452ae648 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -7402,6 +7402,7 @@ static int instance_rmdir(const char *name)
 
         tracing_set_nop(tr);
         event_trace_del_tracer(tr);
+        ftrace_clear_pids(tr);
         ftrace_destroy_function_files(tr);
         tracefs_remove_recursive(tr->dir);
         free_trace_buffers(tr);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index ae1cce91fead..d19d52d600d6 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -896,6 +896,7 @@ int using_ftrace_ops_list_func(void);
 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer);
 void ftrace_init_tracefs_toplevel(struct trace_array *tr,
                                   struct dentry *d_tracer);
+void ftrace_clear_pids(struct trace_array *tr);
 #else
 static inline int ftrace_trace_task(struct trace_array *tr)
 {
@@ -914,6 +915,7 @@ ftrace_init_global_array_ops(struct trace_array *tr) { }
 static inline void ftrace_reset_array_ops(struct trace_array *tr) { }
 static inline void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d) { }
 static inline void ftrace_init_tracefs_toplevel(struct trace_array *tr, struct dentry *d) { }
+static inline void ftrace_clear_pids(struct trace_array *tr) { }
 /* ftace_func_t type is not defined, use macro instead of static inline */
 #define ftrace_init_array_ops(tr, func) do { } while (0)
 #endif /* CONFIG_FUNCTION_TRACER */