On 14 Sep 2021, at 11:27 AM, sunyucong@gmail.com wrote:

quoted

+static int poke_kprobe_events(bool add, const char *name, bool retprobe, uint64_t offset)
+{
+       int fd, ret = 0;

This patch introduced a warning/error in CI

libbpf.c: In function ‘poke_kprobe_events’:
648 libbpf.c:9063:37: error: ‘%s’ directive output may be truncated
writing up to 127 bytes into a region of size between 62 and 189
[-Werror=format-truncation=]
649 9063 | snprintf(cmd, sizeof(cmd), "%c:%s %s",
650 | ^~
651 In file included from /usr/include/stdio.h:867,
652 from libbpf.c:17:
653 /usr/include/x86_64-linux-gnu/bits/stdio2.h:67:10: note:
‘__builtin___snprintf_chk’ output between 4 and 258 bytes into a
destination of size 192
654 67 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
655 | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
656 68 | __bos (__s), __fmt, __va_arg_pack ());
657 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

That happened because:

+	char cmd[192] = {}, probename[128] = {}, probefunc[128] = {};

was changed from original patch without initializing those to '\0' instead.