linux/samples/tracepoints/tracepoint-probe-sample2.c
Mathieu Desnoyers 2504ea5edf tracepoints: samples, fix teardown
Impact: fix a bug in sample tracepoints

Need a tracepoint_synchronize_unregister() before the end of exit() to
make sure every probe callers have exited the non preemptible section
and thus are not executing the probe code anymore.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 09:01:30 +01:00

44 lines
913 B
C

/*
* tracepoint-probe-sample2.c
*
* 2nd sample tracepoint probes.
*/
#include <linux/module.h>
#include <linux/fs.h>
#include "tp-samples-trace.h"
/*
* Here the caller only guarantees locking for struct file and struct inode.
* Locking must therefore be done in the probe to use the dentry.
*/
static void probe_subsys_event(struct inode *inode, struct file *file)
{
printk(KERN_INFO "Event is encountered with inode number %lu\n",
inode->i_ino);
}
int __init tp_sample_trace_init(void)
{
int ret;
ret = register_trace_subsys_event(probe_subsys_event);
WARN_ON(ret);
return 0;
}
module_init(tp_sample_trace_init);
void __exit tp_sample_trace_exit(void)
{
unregister_trace_subsys_event(probe_subsys_event);
tracepoint_synchronize_unregister();
}
module_exit(tp_sample_trace_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Tracepoint Probes Samples");