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authorSteven Rostedt (Red Hat) <srostedt@redhat.com>2013-03-04 23:26:06 -0500
committerSteven Rostedt <rostedt@goodmis.org>2013-03-15 00:34:57 -0400
commit873c642f5964b260480850040dec21e42d0ae4e4 (patch)
treef240e11becc378584fe3892394d735e6bb865ac7
parent575380da8b46969a2c6a7e14a51056a63b30fe2e (diff)
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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 <rostedt@goodmis.org>
-rw-r--r--kernel/trace/trace.c10
-rw-r--r--kernel/trace/trace.h2
-rw-r--r--kernel/trace/trace_events.c10
3 files changed, 16 insertions, 6 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index b5b25b6..c8a852a 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -912,9 +912,15 @@ void tracing_reset_current(int cpu)
tracing_reset(&global_trace, cpu);
}
-void tracing_reset_current_online_cpus(void)
+void tracing_reset_all_online_cpus(void)
{
- tracing_reset_online_cpus(&global_trace);
+ struct trace_array *tr;
+
+ mutex_lock(&trace_types_lock);
+ list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+ tracing_reset_online_cpus(tr);
+ }
+ mutex_unlock(&trace_types_lock);
}
#define SAVED_CMDLINES 128
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 6728a24..fa60b29 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -496,7 +496,7 @@ int tracing_is_enabled(void);
void tracing_reset(struct trace_array *tr, int cpu);
void tracing_reset_online_cpus(struct trace_array *tr);
void tracing_reset_current(int cpu);
-void tracing_reset_current_online_cpus(void);
+void tracing_reset_all_online_cpus(void);
int tracing_open_generic(struct inode *inode, struct file *filp);
struct dentry *trace_create_file(const char *name,
umode_t mode,
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 9a7dc4b..a376ab5 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,