Messages in this thread Patch in this message | | | From | Kamal Mostafa <> | Subject | [PATCH 3.19.y-ckt 138/160] ftrace/module: Call clean up function when module init fails early | Date | Tue, 19 Jan 2016 17:06:56 -0800 |
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3.19.8-ckt13 -stable review patch. If anyone has any objections, please let me know.
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From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
commit 049fb9bd416077b3622d317a45796be4f2431df3 upstream.
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()" Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- include/linux/ftrace.h | 1 + kernel/module.c | 6 ++++++ 2 files changed, 7 insertions(+)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 6cd8c0e..47420d4 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -575,6 +575,7 @@ 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 8942456..bd784c4 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -3386,6 +3386,12 @@ static int load_module(struct load_info *info, const char __user *uargs, synchronize_rcu(); 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); module_deallocate(mod, info); free_copy: free_copy(info); -- 1.9.1
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