From 75e8387685f6c65feb195a4556110b58f852b848 Mon Sep 17 00:00:00 2001 From: Zhou Chengming Date: Fri, 25 Aug 2017 21:49:37 +0800 Subject: perf/ftrace: Fix double traces of perf on ftrace:function When running perf on the ftrace:function tracepoint, there is a bug which can be reproduced by: perf record -e ftrace:function -a sleep 20 & perf record -e ftrace:function ls perf script ls 10304 [005] 171.853235: ftrace:function: perf_output_begin ls 10304 [005] 171.853237: ftrace:function: perf_output_begin ls 10304 [005] 171.853239: ftrace:function: task_tgid_nr_ns ls 10304 [005] 171.853240: ftrace:function: task_tgid_nr_ns ls 10304 [005] 171.853242: ftrace:function: __task_pid_nr_ns ls 10304 [005] 171.853244: ftrace:function: __task_pid_nr_ns We can see that all the function traces are doubled. The problem is caused by the inconsistency of the register function perf_ftrace_event_register() with the probe function perf_ftrace_function_call(). The former registers one probe for every perf_event. And the latter handles all perf_events on the current cpu. So when two perf_events on the current cpu, the traces of them will be doubled. So this patch adds an extra parameter "event" for perf_tp_event, only send sample data to this event when it's not NULL. Signed-off-by: Zhou Chengming Reviewed-by: Jiri Olsa Acked-by: Steven Rostedt (VMware) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: acme@kernel.org Cc: alexander.shishkin@linux.intel.com Cc: huawei.libin@huawei.com Link: http://lkml.kernel.org/r/1503668977-12526-1-git-send-email-zhouchengming1@huawei.com Signed-off-by: Ingo Molnar --- kernel/trace/trace_kprobe.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/trace/trace_kprobe.c') diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index c9b5aa10fbf9..8a907e12b6b9 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1200,7 +1200,7 @@ kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) memset(&entry[1], 0, dsize); store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, - head, NULL); + head, NULL, NULL); } NOKPROBE_SYMBOL(kprobe_perf_func); @@ -1236,7 +1236,7 @@ kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, entry->ret_ip = (unsigned long)ri->ret_addr; store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, - head, NULL); + head, NULL, NULL); } NOKPROBE_SYMBOL(kretprobe_perf_func); #endif /* CONFIG_PERF_EVENTS */ -- cgit