From 873c642f5964b260480850040dec21e42d0ae4e4 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Mon, 4 Mar 2013 23:26:06 -0500 Subject: tracing: Clear all trace buffers when unloaded module event was used Currently we do not know what buffer a module event was enabled in. On unload, it is safest to clear all buffer instances, not just the top level buffer. Todo: Clear only the buffer that the event was used in. The infrastructure is there to do this, but it makes the code a bit more complex. Lets get the current code vetted before we add that. Signed-off-by: Steven Rostedt --- kernel/trace/trace_events.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'kernel/trace/trace_events.c') diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 9a7dc4bf1171..a376ab5eec5c 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1649,14 +1649,18 @@ static void trace_module_remove_events(struct module *mod) list_del(&file_ops->list); kfree(file_ops); } + up_write(&trace_event_mutex); /* * It is safest to reset the ring buffer if the module being unloaded - * registered any events that were used. + * registered any events that were used. The only worry is if + * a new module gets loaded, and takes on the same id as the events + * of this module. When printing out the buffer, traced events left + * over from this module may be passed to the new module events and + * unexpected results may occur. */ if (clear_trace) - tracing_reset_current_online_cpus(); - up_write(&trace_event_mutex); + tracing_reset_all_online_cpus(); } static int trace_module_notify(struct notifier_block *self, -- cgit v1.2.1