On Fri, 7 Mar 2025 12:20:00 -0500 Steven Rostedt <[email protected]> wrote:
> On Thu, 6 Mar 2025 15:21:44 +0900 > "Masami Hiramatsu (Google)" <[email protected]> wrote: > > > When unloading module, the tprobe events are not correctly cleaned > > up. Thus it becomes `fprobe-event` and never be enabled again even > > if loading the same module again. > > > > For example; > > > > # cd /sys/kernel/tracing > > # modprobe trace_events_sample > > # echo 't:my_tprobe foo_bar' >> dynamic_events > > # cat dynamic_events > > t:tracepoints/my_tprobe foo_bar > > # rmmod trace_events_sample > > # cat dynamic_events > > f:tracepoints/my_tprobe foo_bar > > > > As you can see, the second time my_tprobe starts with 'f' instead > > of 't'. > > > > This cleans up (unregister) the tprobe events when module is > > unloaded. > > After applying this, I tried it out: > > # cd /sys/kernel/tracing > # modprobe trace_events_sample > # echo 't:my_tprobe foo_bar a=$arg1' > dynamic_events > # echo 1 > events/tracepoints/enable > [wait] > # echo 0 > events/tracepoints/enable > # cat trace > # tracer: nop > # > # entries-in-buffer/entries-written: 13/13 #P:8 > # > # _-----=> irqs-off/BH-disabled > # / _----=> need-resched > # | / _---=> hardirq/softirq > # || / _--=> preempt-depth > # ||| / _-=> migrate-disable > # |||| / delay > # TASK-PID CPU# ||||| TIMESTAMP FUNCTION > # | | | ||||| | | > event-sample-1041 [005] ...1. 1957.632897: my_tprobe: > (__probestub_foo_bar+0x4/0x20 [trace_events_sample]) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1958.656935: my_tprobe: > (__probestub_foo_bar+0x4/0x20 [trace_events_sample]) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1959.680883: my_tprobe: > (__probestub_foo_bar+0x4/0x20 [trace_events_sample]) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1960.704855: my_tprobe: > (__probestub_foo_bar+0x4/0x20 [trace_events_sample]) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1961.728977: my_tprobe: > (__probestub_foo_bar+0x4/0x20 [trace_events_sample]) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1962.751822: my_tprobe: > (__probestub_foo_bar+0x4/0x20 [trace_events_sample]) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1963.776834: my_tprobe: > (__probestub_foo_bar+0x4/0x20 [trace_events_sample]) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1964.800748: my_tprobe: > (__probestub_foo_bar+0x4/0x20 [trace_events_sample]) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1965.824788: my_tprobe: > (__probestub_foo_bar+0x4/0x20 [trace_events_sample]) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1966.848789: my_tprobe: > (__probestub_foo_bar+0x4/0x20 [trace_events_sample]) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1967.872902: my_tprobe: > (__probestub_foo_bar+0x4/0x20 [trace_events_sample]) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1968.896754: my_tprobe: > (__probestub_foo_bar+0x4/0x20 [trace_events_sample]) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1969.920737: my_tprobe: > (__probestub_foo_bar+0x4/0x20 [trace_events_sample]) a=0xffffffffc006c186 > # rmmod trace_events_sample > # cat trace > # tracer: nop > # > # entries-in-buffer/entries-written: 13/13 #P:8 > # > # _-----=> irqs-off/BH-disabled > # / _----=> need-resched > # | / _---=> hardirq/softirq > # || / _--=> preempt-depth > # ||| / _-=> migrate-disable > # |||| / delay > # TASK-PID CPU# ||||| TIMESTAMP FUNCTION > # | | | ||||| | | > event-sample-1041 [005] ...1. 1957.632897: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1958.656935: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1959.680883: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1960.704855: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1961.728977: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1962.751822: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1963.776834: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1964.800748: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1965.824788: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1966.848789: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1967.872902: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1968.896754: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1969.920737: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > > # modprobe trace_events_sample > # echo 1 > events/tracepoints/enable > # cat trace > # tracer: nop > # > # entries-in-buffer/entries-written: 13/13 #P:8 > # > # _-----=> irqs-off/BH-disabled > # / _----=> need-resched > # | / _---=> hardirq/softirq > # || / _--=> preempt-depth > # ||| / _-=> migrate-disable > # |||| / delay > # TASK-PID CPU# ||||| TIMESTAMP FUNCTION > # | | | ||||| | | > event-sample-1041 [005] ...1. 1957.632897: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1958.656935: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1959.680883: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1960.704855: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1961.728977: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1962.751822: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1963.776834: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1964.800748: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1965.824788: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1966.848789: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1967.872902: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1968.896754: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > event-sample-1041 [005] ...1. 1969.920737: my_tprobe: > (0xffffffffc00620b4) a=0xffffffffc006c186 > > Tracing doesn't restart. Ah, I see. __unregister_trace_fprobe() clean up fp. static void __unregister_trace_fprobe(struct trace_fprobe *tf) { if (trace_fprobe_is_registered(tf)) { unregister_fprobe(&tf->fp); memset(&tf->fp, 0, sizeof(tf->fp)); <---- this This will cleanup the callbacks. Let me update it. Thanks! > > -- Steve > -- Masami Hiramatsu (Google) <[email protected]>
