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Commit 049fb9bd authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
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ftrace/module: Call clean up function when module init fails early 

If the module init code fails after calling ftrace_module_init() and before
calling do_init_module(), we can suffer from a memory leak. This is because
ftrace_module_init() allocates pages to store the locations that ftrace
hooks are placed in the module text. If do_init_module() fails, it still
calls the MODULE_GOING notifiers which will tell ftrace to do a clean up of
the pages it allocated for the module. But if load_module() fails before
then, the pages allocated by ftrace_module_init() will never be freed.

Call ftrace_release_mod() on the module if load_module() fails before
getting to do_init_module().

Link: http://lkml.kernel.org/r/567CEA31.1070507@intel.com



Reported-by: default avatar"Qiu, PeiyangX" <peiyangx.qiu@intel.com>
Fixes: a949ae56 "ftrace/module: Hardcode ftrace_module_init() call into load_module()"
Cc: stable@vger.kernel.org # v2.6.38+
Acked-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent f36d1be2

include/linux/ftrace.h

+1 −0
Original line number Original line 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 int skip_trace(unsigned long ip);

extern void ftrace_module_init(struct module *mod);

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_disable_daemon(void);

extern void ftrace_enable_daemon(void);

extern void ftrace_enable_daemon(void);

kernel/module.c

+6 −0
Original line number Original line Diff line number Diff line
@@ -3571,6 +3571,12 @@ static int load_module(struct load_info *info, const char __user *uargs, 
	synchronize_sched();

	synchronize_sched();

	mutex_unlock(&module_mutex);

	mutex_unlock(&module_mutex);

 free_module:

 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() */

	/* Free lock-classes; relies on the preceding sync_rcu() */

	lockdep_free_key_range(mod->module_core, mod->core_size);

	lockdep_free_key_range(mod->module_core, mod->core_size);