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authorZhou Chengming <zhouchengming1@huawei.com>2017-08-25 16:49:37 +0300
committerIngo Molnar <mingo@kernel.org>2017-08-29 14:29:29 +0300
commit75e8387685f6c65feb195a4556110b58f852b848 (patch)
tree1c8f8318f1fe76197a2a0d2fcfc53992b1855b30 /kernel/trace/trace_syscalls.c
parentf12f42acdbb577a12eecfcebbbec41c81505c4dc (diff)
downloadlinux-75e8387685f6c65feb195a4556110b58f852b848.tar.xz
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 <zhouchengming1@huawei.com> Reviewed-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> 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 <mingo@kernel.org>
Diffstat (limited to 'kernel/trace/trace_syscalls.c')
-rw-r--r--kernel/trace/trace_syscalls.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 5e10395da88e..74d9a86eccc0 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -596,7 +596,7 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
(unsigned long *)&rec->args);
perf_trace_buf_submit(rec, size, rctx,
sys_data->enter_event->event.type, 1, regs,
- head, NULL);
+ head, NULL, NULL);
}
static int perf_sysenter_enable(struct trace_event_call *call)
@@ -667,7 +667,7 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
rec->nr = syscall_nr;
rec->ret = syscall_get_return_value(current, regs);
perf_trace_buf_submit(rec, size, rctx, sys_data->exit_event->event.type,
- 1, regs, head, NULL);
+ 1, regs, head, NULL, NULL);
}
static int perf_sysexit_enable(struct trace_event_call *call)