The compiler warns about a tautological comparison in mremap_test.c: "pointer comparison always evaluates to false [-Wtautological-compare]"

This occurs when checking for unsigned overflow: if (addr + c.dest_alignment < addr)

Cast 'addr' to 'unsigned long long' to ensure the comparison is performed with a wider type, correctly detecting potential overflow and resolving the warning.

Signed-off-by: Wake Liu wakel@google.com --- tools/testing/selftests/mm/mremap_test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/mm/mremap_test.c b/tools/testing/selftests/mm/mremap_test.c index bf2863b102e3..c4933f4cbd48 100644 --- a/tools/testing/selftests/mm/mremap_test.c +++ b/tools/testing/selftests/mm/mremap_test.c @@ -1032,7 +1032,7 @@ static long long remap_region(struct config c, unsigned int threshold_mb, /* Don't destroy existing mappings unless expected to overlap */ while (!is_remap_region_valid(addr, c.region_size) && !c.overlapping) { /* Check for unsigned overflow */ - if (addr + c.dest_alignment < addr) { + if ((unsigned long long)addr + c.dest_alignment < (unsigned long long)addr) { ksft_print_msg("Couldn't find a valid region to remap to\n"); ret = -1; goto clean_up_src;