Commit 2626820d authored Jan 07, 2016 by Linus Torvalds

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

parents b06f3a16 049fb9bd

include/linux/ftrace.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -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);

kernel/module.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -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);

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