perf probe: Skip same probe address for a given line

Fix to skip making a same probe address on given line.

Since a DWARF line info contains several entries for one line with
different column, perf probe will make a different probe on same address
if user specifies a probe point by "function:line" or "file:line".

e.g.
 $ perf probe -D kernel_read:8
 p:probe/kernel_read_L8 kernel_read+39
 p:probe/kernel_read_L8_1 kernel_read+39

This skips such duplicated probe addresses.

Committer testing:

  # uname -a
  Linux quaco 5.3.0+ #2 SMP Thu Sep 19 16:13:22 -03 2019 x86_64 x86_64 x86_64 GNU/Linux
  #

Before:

  # perf probe -D kernel_read:8
  p:probe/kernel_read _text+3115191
  p:probe/kernel_read_1 _text+3115191
  #

After:

  # perf probe -D kernel_read:8
  p:probe/kernel_read _text+3115191
  #

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lore.kernel.org/lkml/156886447061.10772.4261569305869149178.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 505905fc21c54440e3fab59966ec09d59026ef7d..cd9f95e5044e3df7f0155b7a49862e62bb7f75d6 100644 (file)
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1245,6 +1245,17 @@ static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
        return n;
 }
 
+static bool trace_event_finder_overlap(struct trace_event_finder *tf)
+{
+       int i;
+
+       for (i = 0; i < tf->ntevs; i++) {
+               if (tf->pf.addr == tf->tevs[i].point.address)
+                       return true;
+       }
+       return false;
+}
+
 /* Add a found probe point into trace event list */
 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
 {
@@ -1255,6 +1266,14 @@ static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
        struct perf_probe_arg *args = NULL;
        int ret, i;
 
+       /*
+        * For some reason (e.g. different column assigned to same address)
+        * This callback can be called with the address which already passed.
+        * Ignore it first.
+        */
+       if (trace_event_finder_overlap(tf))
+               return 0;
+
        /* Check number of tevs */
        if (tf->ntevs == tf->max_tevs) {
                pr_warning("Too many( > %d) probe point found.\n",