* [PATCH] ftrace/module: Call clean up function when module init fails early
@ 2016-01-06 2:05 Steven Rostedt
2016-01-06 2:09 ` [PATCH v2] " Steven Rostedt
0 siblings, 1 reply; 3+ messages in thread
From: Steven Rostedt @ 2016-01-06 2:05 UTC (permalink / raw)
To: Rusty Russell; +Cc: LKML, Zhang, Yanmin, Qiu, PeiyangX
[ Rusty, I'm currently testing this patch. Can you give me an Acked-by? ]
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+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/module.c | 6 ++++++
1 file changed, 6 insertions(+)
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);
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH v2] ftrace/module: Call clean up function when module init fails early
2016-01-06 2:05 [PATCH] ftrace/module: Call clean up function when module init fails early Steven Rostedt
@ 2016-01-06 2:09 ` Steven Rostedt
2016-01-06 23:44 ` Rusty Russell
0 siblings, 1 reply; 3+ messages in thread
From: Steven Rostedt @ 2016-01-06 2:09 UTC (permalink / raw)
To: Rusty Russell; +Cc: LKML, Zhang, Yanmin, Qiu, PeiyangX
[ Bah, I forgot to commit the ftrace.h part, lucky I test on another
box than what I compile test on ;-) ]
>From d2621b2c51a14007cd2ca5ec94fa20a486a31244 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Tue, 5 Jan 2016 20:32:47 -0500
Subject: [PATCH] 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+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
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 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);
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] ftrace/module: Call clean up function when module init fails early
2016-01-06 2:09 ` [PATCH v2] " Steven Rostedt
@ 2016-01-06 23:44 ` Rusty Russell
0 siblings, 0 replies; 3+ messages in thread
From: Rusty Russell @ 2016-01-06 23:44 UTC (permalink / raw)
To: Steven Rostedt; +Cc: LKML, Zhang, Yanmin, Qiu, PeiyangX
Steven Rostedt <rostedt@goodmis.org> writes:
> [ Bah, I forgot to commit the ftrace.h part, lucky I test on another
> box than what I compile test on ;-) ]
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cheers,
Rusty.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2016-01-06 2:09 ` [PATCH v2] " Steven Rostedt
2016-01-06 23:44 ` Rusty Russell
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