2504ea5edf
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>
57 lines
1.2 KiB
C
57 lines
1.2 KiB
C
/*
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* tracepoint-probe-sample.c
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*
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* sample tracepoint probes.
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*/
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#include <linux/module.h>
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#include <linux/file.h>
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#include <linux/dcache.h>
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#include "tp-samples-trace.h"
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/*
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* Here the caller only guarantees locking for struct file and struct inode.
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* Locking must therefore be done in the probe to use the dentry.
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*/
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static void probe_subsys_event(struct inode *inode, struct file *file)
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{
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path_get(&file->f_path);
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dget(file->f_path.dentry);
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printk(KERN_INFO "Event is encountered with filename %s\n",
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file->f_path.dentry->d_name.name);
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dput(file->f_path.dentry);
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path_put(&file->f_path);
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}
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static void probe_subsys_eventb(void)
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{
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printk(KERN_INFO "Event B is encountered\n");
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}
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int __init tp_sample_trace_init(void)
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{
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int ret;
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ret = register_trace_subsys_event(probe_subsys_event);
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WARN_ON(ret);
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ret = register_trace_subsys_eventb(probe_subsys_eventb);
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WARN_ON(ret);
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return 0;
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}
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module_init(tp_sample_trace_init);
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void __exit tp_sample_trace_exit(void)
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{
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unregister_trace_subsys_eventb(probe_subsys_eventb);
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unregister_trace_subsys_event(probe_subsys_event);
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tracepoint_synchronize_unregister();
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}
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module_exit(tp_sample_trace_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Mathieu Desnoyers");
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MODULE_DESCRIPTION("Tracepoint Probes Samples");
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