From: Shawn Landden <sh...@git.icu>

This strncat() is safe because the buffer was allocated with zalloc(),
however gcc doesn't know that. Since the string always has 4 non-null
bytes, just use memcpy() here.

    CC       /home/shawn/linux/tools/perf/util/data-convert-bt.o
  In file included from /usr/include/string.h:494,
                   from /home/shawn/linux/tools/lib/traceevent/event-parse.h:27,
                   from util/data-convert-bt.c:22:
  In function ‘strncat’,
      inlined from ‘string_set_value’ at util/data-convert-bt.c:274:4:
  /usr/include/powerpc64le-linux-gnu/bits/string_fortified.h:136:10: error: 
‘__builtin_strncat’ output may be truncated copying 4 bytes from a string of 
length 4 [-Werror=stringop-truncation]
    136 |   return __builtin___strncat_chk (__dest, __src, __len, __bos 
(__dest));
        |          
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Shawn Landden <sh...@git.icu>
Cc: Adrian Hunter <adrian.hun...@intel.com>
Cc: Jiri Olsa <jo...@redhat.com>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Wang Nan <wangn...@huawei.com>
LPU-Reference: 20190518183238.10954-1-sh...@git.icu
Link: https://lkml.kernel.org/n/tip-289f1jice17ta7tr3tstm...@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com>
---
 tools/perf/util/data-convert-bt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/data-convert-bt.c 
b/tools/perf/util/data-convert-bt.c
index e0311c9750ad..9097543a818b 100644
--- a/tools/perf/util/data-convert-bt.c
+++ b/tools/perf/util/data-convert-bt.c
@@ -271,7 +271,7 @@ static int string_set_value(struct bt_ctf_field *field, 
const char *string)
                                if (i > 0)
                                        strncpy(buffer, string, i);
                        }
-                       strncat(buffer + p, numstr, 4);
+                       memcpy(buffer + p, numstr, 4);
                        p += 3;
                }
        }
-- 
2.20.1

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