Commit a8227415 authored by Alexander Z Lam's avatar Alexander Z Lam Committed by Steven Rostedt
Browse files

tracing: Protect ftrace_trace_arrays list in trace_events.c

There are multiple places where the ftrace_trace_arrays list is accessed in
trace_events.c without the trace_types_lock held.

Link: http://lkml.kernel.org/r/1372732674-22726-1-git-send-email-azl@google.com



Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: default avatarAlexander Z Lam <azl@google.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 2d71619c
......@@ -266,7 +266,7 @@ static struct tracer *trace_types __read_mostly;
/*
* trace_types_lock is used to protect the trace_types list.
*/
static DEFINE_MUTEX(trace_types_lock);
DEFINE_MUTEX(trace_types_lock);
/*
* serialize the access of the ring buffer
......
......@@ -224,6 +224,8 @@ enum {
extern struct list_head ftrace_trace_arrays;
extern struct mutex trace_types_lock;
/*
* The global tracer (top) should be the first trace array added,
* but we check the flag anyway.
......
......@@ -1008,6 +1008,7 @@ static int subsystem_open(struct inode *inode, struct file *filp)
int ret;
/* Make sure the system still exists */
mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex);
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
list_for_each_entry(dir, &tr->systems, list) {
......@@ -1023,6 +1024,7 @@ static int subsystem_open(struct inode *inode, struct file *filp)
}
exit_loop:
mutex_unlock(&event_mutex);
mutex_unlock(&trace_types_lock);
if (!system)
return -ENODEV;
......@@ -1617,6 +1619,7 @@ static void __add_event_to_tracers(struct ftrace_event_call *call,
int trace_add_event_call(struct ftrace_event_call *call)
{
int ret;
mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex);
ret = __register_event(call, NULL);
......@@ -1624,11 +1627,13 @@ int trace_add_event_call(struct ftrace_event_call *call)
__add_event_to_tracers(call, NULL);
mutex_unlock(&event_mutex);
mutex_unlock(&trace_types_lock);
return ret;
}
/*
* Must be called under locking both of event_mutex and trace_event_sem.
* Must be called under locking of trace_types_lock, event_mutex and
* trace_event_sem.
*/
static void __trace_remove_event_call(struct ftrace_event_call *call)
{
......@@ -1640,11 +1645,13 @@ static void __trace_remove_event_call(struct ftrace_event_call *call)
/* Remove an event_call */
void trace_remove_event_call(struct ftrace_event_call *call)
{
mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex);
down_write(&trace_event_sem);
__trace_remove_event_call(call);
up_write(&trace_event_sem);
mutex_unlock(&event_mutex);
mutex_unlock(&trace_types_lock);
}
#define for_each_event(event, start, end) \
......@@ -1788,6 +1795,7 @@ static int trace_module_notify(struct notifier_block *self,
{
struct module *mod = data;
mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex);
switch (val) {
case MODULE_STATE_COMING:
......@@ -1798,6 +1806,7 @@ static int trace_module_notify(struct notifier_block *self,
break;
}
mutex_unlock(&event_mutex);
mutex_unlock(&trace_types_lock);
return 0;
}
......
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