Messages in this thread Patch in this message | | | Date | Thu, 7 Jan 2016 13:25:23 -0500 | From | Steven Rostedt <> | Subject | [GIT PULL] ftrace/module: Call clean up function when module init fails early |
| |
Linus,
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()).
Please pull the latest trace-v4.4-rc4-4 tree, which can be found at:
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git trace-v4.4-rc4-4
Tag SHA1: 4bc8d900c8ad045c130aff2481aabefada00be4f Head SHA1: 049fb9bd416077b3622d317a45796be4f2431df3
Steven Rostedt (Red Hat) (1): ftrace/module: Call clean up function when module init fails early
---- include/linux/ftrace.h | 1 + kernel/module.c | 6 ++++++ 2 files changed, 7 insertions(+) --------------------------- commit 049fb9bd416077b3622d317a45796be4f2431df3 Author: Steven Rostedt (Red Hat) <rostedt@goodmis.org> Date: Tue Jan 5 20:32:47 2016 -0500
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: "Qiu, PeiyangX" <peiyangx.qiu@intel.com> Fixes: a949ae560a511 "ftrace/module: Hardcode ftrace_module_init() call into load_module()" Cc: stable@vger.kernel.org # v2.6.38+ Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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);
| |