The "initial_nr_hugepages" variable is unsigned long so it takes up to 20 characters to print, plus 1 more character for the NUL terminator. Unfortunately, this buffer is not quite large enough for the terminator to fit. Also use snprintf() for a belt and suspenders approach. Fixes: fb9293b6b015 ("selftests/mm: compaction_test: fix bogus test success and reduce probability of OOM-killer invocation") Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> --- tools/testing/selftests/mm/compaction_test.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/mm/compaction_test.c b/tools/testing/selftests/mm/compaction_test.c index e140558e6f53..2c3a0eb6b22d 100644 --- a/tools/testing/selftests/mm/compaction_test.c +++ b/tools/testing/selftests/mm/compaction_test.c @@ -89,9 +89,10 @@ int check_compaction(unsigned long mem_free, unsigned long hugepage_size, int fd, ret = -1; int compaction_index = 0; char nr_hugepages[20] = {0}; - char init_nr_hugepages[20] = {0}; + char init_nr_hugepages[24] = {0}; - sprintf(init_nr_hugepages, "%lu", initial_nr_hugepages); + snprintf(init_nr_hugepages, sizeof(init_nr_hugepages), + "%lu", initial_nr_hugepages); /* We want to test with 80% of available memory. Else, OOM killer comes in to play */ -- 2.43.0