On Mon, 2013-07-01 at 15:31 -0700, Alexander Z Lam wrote:
> There are multiple places where the ftrace_trace_arrays list is accessed in
> trace_events.c without the trace_types_lock held.
Hmm, doesn't compile. Not a complete patch? trace_types_lock is local to
trace.c, and needs to be in trace.h and non static.
-- Steve
>
> Cc: David Sharp <dhsh...@google.com>
> Cc: Alexander Z Lam <lambchop...@gmail.com>
> Signed-off-by: Alexander Z Lam <a...@google.com>
> ---
> kernel/trace/trace_events.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
> index 6db3290..26351cc 100644
> --- a/kernel/trace/trace_events.c
> +++ b/kernel/trace/trace_events.c
> @@ -1586,6 +1586,7 @@ 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);
> @@ -1593,11 +1594,13 @@ 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)
> {
> @@ -1609,11 +1612,13 @@ 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) \
> @@ -1757,6 +1762,7 @@ 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:
> @@ -1767,6 +1773,7 @@ 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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