perf probe: Fix to handle errors in line_range searching

As Namhyung reported(https://lkml.org/lkml/2014/4/1/89),
current perf-probe -L option doesn't handle errors in line-range
searching correctly. It causes a SEGV if an error occured in the
line-range searching.

  ----
  $ perf probe -x ./perf -v -L map__load
  Open Debuginfo file: /home/namhyung/project/linux/tools/perf/perf
  fname: util/map.c, lineno:153
  New line range: 153 to 2147483647
  path: (null)
  Segmentation fault (core dumped)
  ----

This is because line_range_inline_cb() ignores errors
from find_line_range_by_line() which means that lr->path is
already freed on the error path in find_line_range_by_line().
As a result, get_real_path() accesses the lr->path and it
causes a NULL pointer exception.

This fixes line_range_inline_cb() to handle the error correctly,
and report it to the caller.

Anyway, this just fixes a possible SEGV bug, Namhyung's patch
is also required.

Reported-by: Namhyung Kim <[email protected]>
Signed-off-by: Masami Hiramatsu <[email protected]>
Acked-by: Namhyung Kim <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Jiri Olsa <[email protected]>

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 3bf0c8cdccb7225d3035eb32e55c81944686ec4f..fae274e72fe66168d3882af247fdd2aecc9b1e12 100644 (file)
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1475,14 +1475,15 @@ static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
 
 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
 {
-       find_line_range_by_line(in_die, data);
+       int ret = find_line_range_by_line(in_die, data);
 
        /*
         * We have to check all instances of inlined function, because
         * some execution paths can be optimized out depends on the
-        * function argument of instances
+        * function argument of instances. However, if an error occurs,
+        * it should be handled by the caller.
         */
-       return 0;
+       return ret < 0 ? ret : 0;
 }
 
 /* Search function definition from function name */