Merge tag 'trace-v4.4-rc4-4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull ftrace fix from Steven Rostedt:
 "PeiyangX Qiu reported that if a module fails to load between calling
  ftrace_module_init() and do_init_module() that the allocations made in
  ftrace_module_init() will not be freed, resulting in a memory leak.

  The solution is to call ftrace_release_mod() on the failing module in
  the fail path befor do_init_module() is called.  This will remove any
  allocations made for that module, and nothing if ftrace_module_init()
  wasn't called yet for that module.

  Note, once do_init_module() is called, the MODULE_GOING notifiers are
  called for the failed module, which calls into the ftrace code to do
  the proper clean up (basically calling ftrace_release_mod())"

* tag 'trace-v4.4-rc4-4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace/module: Call clean up function when module init fails early

2 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index eae6548efbf0..60048c50404e 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -586,6 +586,7 @@ extern int ftrace_arch_read_dyn_info(char *buf, int size);
 
 extern int skip_trace(unsigned long ip);
 extern void ftrace_module_init(struct module *mod);
+extern void ftrace_release_mod(struct module *mod);
 
 extern void ftrace_disable_daemon(void);
 extern void ftrace_enable_daemon(void);
diff --git a/kernel/module.c b/kernel/module.c
index 8f051a106676..38c7bd5583ff 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3571,6 +3571,12 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	synchronize_sched();
 	mutex_unlock(&module_mutex);
  free_module:
+	/*
+	 * Ftrace needs to clean up what it initialized.
+	 * This does nothing if ftrace_module_init() wasn't called,
+	 * but it must be called outside of module_mutex.
+	 */
+	ftrace_release_mod(mod);
 	/* Free lock-classes; relies on the preceding sync_rcu() */
 	lockdep_free_key_range(mod->module_core, mod->core_size);