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tracing: Clear all trace buffers when unloaded module event was used

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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>
This commit is contained in:
Steven Rostedt (Red Hat)
2013-03-04 23:26:06 -05:00
committed by Steven Rostedt
parent 575380da8b
commit 873c642f59
3 changed files with 16 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
kernel/trace/trace.c
View File

@@ -912,9 +912,15 @@ void tracing_reset_current(int cpu)
tracing_reset(&global_trace, 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 #define SAVED_CMDLINES 128

2
kernel/trace/trace.h
View File

@@ -496,7 +496,7 @@ int tracing_is_enabled(void);
void tracing_reset(struct trace_array *tr, int cpu); void tracing_reset(struct trace_array *tr, int cpu);
void tracing_reset_online_cpus(struct trace_array *tr); void tracing_reset_online_cpus(struct trace_array *tr);
void tracing_reset_current(int cpu); 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); int tracing_open_generic(struct inode *inode, struct file *filp);
struct dentry *trace_create_file(const char *name, struct dentry *trace_create_file(const char *name,
umode_t mode, umode_t mode,

10
kernel/trace/trace_events.c
View File

@@ -1649,14 +1649,18 @@ static void trace_module_remove_events(struct module *mod)
list_del(&file_ops->list); list_del(&file_ops->list);
kfree(file_ops); kfree(file_ops);
} }
up_write(&trace_event_mutex);
/* /*
* It is safest to reset the ring buffer if the module being unloaded * 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) if (clear_trace)
tracing_reset_current_online_cpus(); tracing_reset_all_online_cpus();
up_write(&trace_event_mutex);
} }
static int trace_module_notify(struct notifier_block *self, static int trace_module_notify(struct notifier_block *self,