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tracing: Protect ftrace_trace_arrays list in trace_events.c

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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: Alexander Z Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Alexander Z Lam 2013-07-01 19:37:54 -07:00 committed by Steven Rostedt
parent 2d71619c59
commit a82274151a
3 changed files with 13 additions and 2 deletions
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2
kernel/trace/trace.c
View file

@ -266,7 +266,7 @@ static struct tracer *trace_types __read_mostly;
/* /*
* trace_types_lock is used to protect the trace_types list. * 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 * serialize the access of the ring buffer

2
kernel/trace/trace.h
View file

@ -224,6 +224,8 @@ enum {
extern struct list_head ftrace_trace_arrays; extern struct list_head ftrace_trace_arrays;
extern struct mutex trace_types_lock;
/* /*
* The global tracer (top) should be the first trace array added, * The global tracer (top) should be the first trace array added,
* but we check the flag anyway. * but we check the flag anyway.

11
kernel/trace/trace_events.c
View file

@ -1008,6 +1008,7 @@ static int subsystem_open(struct inode *inode, struct file *filp)
int ret; int ret;
/* Make sure the system still exists */ /* Make sure the system still exists */
mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex); mutex_lock(&event_mutex);
list_for_each_entry(tr, &ftrace_trace_arrays, list) { list_for_each_entry(tr, &ftrace_trace_arrays, list) {
list_for_each_entry(dir, &tr->systems, 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: exit_loop:
mutex_unlock(&event_mutex); mutex_unlock(&event_mutex);
mutex_unlock(&trace_types_lock);
if (!system) if (!system)
return -ENODEV; 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 trace_add_event_call(struct ftrace_event_call *call)
{ {
int ret; int ret;
mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex); mutex_lock(&event_mutex);
ret = __register_event(call, NULL); 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); __add_event_to_tracers(call, NULL);
mutex_unlock(&event_mutex); mutex_unlock(&event_mutex);
mutex_unlock(&trace_types_lock);
return ret; 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) 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 */ /* Remove an event_call */
void trace_remove_event_call(struct ftrace_event_call *call) void trace_remove_event_call(struct ftrace_event_call *call)
{ {
mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex); mutex_lock(&event_mutex);
down_write(&trace_event_sem); down_write(&trace_event_sem);
__trace_remove_event_call(call); __trace_remove_event_call(call);
up_write(&trace_event_sem); up_write(&trace_event_sem);
mutex_unlock(&event_mutex); mutex_unlock(&event_mutex);
mutex_unlock(&trace_types_lock);
} }
#define for_each_event(event, start, end) \ #define for_each_event(event, start, end) \
@ -1788,6 +1795,7 @@ static int trace_module_notify(struct notifier_block *self,
{ {
struct module *mod = data; struct module *mod = data;
mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex); mutex_lock(&event_mutex);
switch (val) { switch (val) {
case MODULE_STATE_COMING: case MODULE_STATE_COMING:
@ -1798,6 +1806,7 @@ static int trace_module_notify(struct notifier_block *self,
break; break;
} }
mutex_unlock(&event_mutex); mutex_unlock(&event_mutex);
mutex_unlock(&trace_types_lock);
return 0; return 0;
} }