Perf does not build with the ubsan (undefined behavior sanitizer) and there is an error that says:
tests/backward-ring-buffer.c:23:45: error: ā%dā directive output may be truncated writing between 1 and 10 bytes into a region of size 8 [-Werror=format-truncation=] snprintf(proc_name, sizeof(proc_name), "p:%d\n", i); This can be reproduced by running (from the tip directory): make -C tools/perf USE_CLANG=1 EXTRA_CFLAGS="-fsanitize=undefined" Th error occurs because they are writing to the 10 byte buffer - the index 'i' of the for loop and the 2 byte hardcoded string. If somehow 'i' was greater than 8 bytes (10 - 2), then the snprintf function would truncate the string. Increasing the size of the buffer fixes the error. Signed-off-by: Numfor Mbiziwo-Tiapo <n...@google.com> --- tools/perf/tests/backward-ring-buffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/tests/backward-ring-buffer.c b/tools/perf/tests/backward-ring-buffer.c index 6d598cc071ae..1a9c3becf5ff 100644 --- a/tools/perf/tests/backward-ring-buffer.c +++ b/tools/perf/tests/backward-ring-buffer.c @@ -18,7 +18,7 @@ static void testcase(void) int i; for (i = 0; i < NR_ITERS; i++) { - char proc_name[10]; + char proc_name[15]; snprintf(proc_name, sizeof(proc_name), "p:%d\n", i); prctl(PR_SET_NAME, proc_name); -- 2.22.0.657.g960e92d24f-goog