[PATCH v5 1/6] kprobes: Remove dependency to the module_mutex

[Jarkko Sakkinen]

Add lock_modules() and unlock_modules() wrappers for acquiring module_mutex
in order to remove the compile time dependency to it.

Cc: linux-mm@xxxxxxxxx
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Suggested-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
---
 include/linux/module.h      | 18 ++++++++++++++++++
 kernel/kprobes.c            |  4 ++--
 kernel/trace/trace_kprobe.c |  4 ++--
 3 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 2e6670860d27..8850b9692b8f 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -705,6 +705,16 @@ static inline bool is_livepatch_module(struct module *mod)
 bool is_module_sig_enforced(void);
 void set_module_sig_enforced(void);
 
+static inline void lock_modules(void)
+{
+	mutex_lock(&module_mutex);
+}
+
+static inline void unlock_modules(void)
+{
+	mutex_unlock(&module_mutex);
+}
+
 #else /* !CONFIG_MODULES... */
 
 static inline struct module *__module_address(unsigned long addr)
@@ -852,6 +862,14 @@ void *dereference_module_function_descriptor(struct module *mod, void *ptr)
 	return ptr;
 }
 
+static inline void lock_modules(void)
+{
+}
+
+static inline void unlock_modules(void)
+{
+}
+
 #endif /* CONFIG_MODULES */
 
 #ifdef CONFIG_SYSFS
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 2e97febeef77..4e46d96d4e16 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -564,7 +564,7 @@ static void kprobe_optimizer(struct work_struct *work)
 	cpus_read_lock();
 	mutex_lock(&text_mutex);
 	/* Lock modules while optimizing kprobes */
-	mutex_lock(&module_mutex);
+	lock_modules();
 
 	/*
 	 * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
@@ -589,7 +589,7 @@ static void kprobe_optimizer(struct work_struct *work)
 	/* Step 4: Free cleaned kprobes after quiesence period */
 	do_free_cleaned_kprobes();
 
-	mutex_unlock(&module_mutex);
+	unlock_modules();
 	mutex_unlock(&text_mutex);
 	cpus_read_unlock();
 
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index aefb6065b508..710ec6a6aa8f 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -122,9 +122,9 @@ static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
 	if (!p)
 		return true;
 	*p = '\0';
-	mutex_lock(&module_mutex);
+	lock_modules();
 	ret = !!find_module(tk->symbol);
-	mutex_unlock(&module_mutex);
+	unlock_modules();
 	*p = ':';
 
 	return ret;
-- 
2.25.1