From: Leo Yan <leo....@linaro.org>

[ Upstream commit 600c787dbf6521d8d07ee717ab7606d5070103ea ]

Based on the following report from Smatch, fix the potential
dereferencing freed memory check.

  tools/perf/util/annotate.c:1125
  disasm_line__parse() error: dereferencing freed memory 'namep'

  tools/perf/util/annotate.c
  1100 static int disasm_line__parse(char *line, const char **namep, char 
**rawp)
  1101 {
  1102         char tmp, *name = ltrim(line);

  [...]

  1114         *namep = strdup(name);
  1115
  1116         if (*namep == NULL)
  1117                 goto out_free_name;

  [...]

  1124 out_free_name:
  1125         free((void *)namep);
                            ^^^^^
  1126         *namep = NULL;
               ^^^^^^
  1127         return -1;
  1128 }

If strdup() fails to allocate memory space for *namep, we don't need to
free memory with pointer 'namep', which is resident in data structure
disasm_line::ins::name; and *namep is NULL pointer for this failure, so
it's pointless to assign NULL to *namep again.

Committer note:

Freeing namep, which is the address of the first entry of the 'struct
ins' that is the first member of struct disasm_line would in fact free
that disasm_line instance, if it was allocated via malloc/calloc, which,
later, would a dereference of freed memory.

Signed-off-by: Leo Yan <leo....@linaro.org>
Acked-by: Jiri Olsa <jo...@kernel.org>
Cc: Adrian Hunter <adrian.hun...@intel.com>
Cc: Alexander Shishkin <alexander.shish...@linux.intel.com>
Cc: Alexey Budankov <alexey.budan...@linux.intel.com>
Cc: Alexios Zavras <alexios.zav...@intel.com>
Cc: Andi Kleen <a...@linux.intel.com>
Cc: Changbin Du <changbin...@intel.com>
Cc: David S. Miller <da...@davemloft.net>
Cc: Davidlohr Bueso <d...@stgolabs.net>
Cc: Eric Saint-Etienne <eric.saint.etie...@oracle.com>
Cc: Jin Yao <yao....@linux.intel.com>
Cc: Konstantin Khlebnikov <khlebni...@yandex-team.ru>
Cc: Mathieu Poirier <mathieu.poir...@linaro.org>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Rasmus Villemoes <li...@rasmusvillemoes.dk>
Cc: Song Liu <songliubrav...@fb.com>
Cc: Suzuki Poulouse <suzuki.poul...@arm.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Thomas Richter <tmri...@linux.ibm.com>
Cc: linux-arm-ker...@lists.infradead.org
Link: http://lkml.kernel.org/r/20190702103420.27540-5-leo....@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 tools/perf/util/annotate.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 09762985c713..b56282041f41 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -1115,16 +1115,14 @@ static int disasm_line__parse(char *line, const char 
**namep, char **rawp)
        *namep = strdup(name);
 
        if (*namep == NULL)
-               goto out_free_name;
+               goto out;
 
        (*rawp)[0] = tmp;
        *rawp = ltrim(*rawp);
 
        return 0;
 
-out_free_name:
-       free((void *)namep);
-       *namep = NULL;
+out:
        return -1;
 }
 
-- 
2.20.1

Reply via email to