[PATCH v9 4/5] selftests/mm: add missing mmap() return checks in pkey tests

From: Hongfu Li

Date: Thu Jul 02 2026 - 02:26:58 EST


Add missing checks against mmap() return value, replace (void *)-1
with MAP_FAILED for better readability and consistency.

Signed-off-by: Hongfu Li <lihongfu@xxxxxxxxxx>
Acked-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
Acked-by: Liam R. Howlett (Oracle) <liam@xxxxxxxxxxxxx>
Reviewed-by: Kevin Brodsky <kevin.brodsky@xxxxxxx>
Tested-by: Kevin Brodsky <kevin.brodsky@xxxxxxx>
---
tools/testing/selftests/mm/pkey-powerpc.h | 2 +-
tools/testing/selftests/mm/pkey_sighandler_tests.c | 2 ++
tools/testing/selftests/mm/protection_keys.c | 12 +++++++-----
3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/mm/pkey-powerpc.h b/tools/testing/selftests/mm/pkey-powerpc.h
index 17bf2d1b0192..2ce85580b404 100644
--- a/tools/testing/selftests/mm/pkey-powerpc.h
+++ b/tools/testing/selftests/mm/pkey-powerpc.h
@@ -126,7 +126,7 @@ static inline void *malloc_pkey_with_mprotect_subpage(long size, int prot, u16 p
size, prot, pkey);
pkey_assert(pkey < NR_PKEYS);
ptr = mmap(NULL, size, prot, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
- pkey_assert(ptr != (void *)-1);
+ pkey_assert(ptr != MAP_FAILED);

ret = syscall(__NR_subpage_prot, ptr, size, NULL);
if (ret) {
diff --git a/tools/testing/selftests/mm/pkey_sighandler_tests.c b/tools/testing/selftests/mm/pkey_sighandler_tests.c
index 188513e94fc5..8f98e6d9349f 100644
--- a/tools/testing/selftests/mm/pkey_sighandler_tests.c
+++ b/tools/testing/selftests/mm/pkey_sighandler_tests.c
@@ -313,6 +313,7 @@ static void test_sigsegv_handler_with_different_pkey_for_stack(void)
/* Set up alternate signal stack that will use the default MPK */
sigstack.ss_sp = mmap(0, STACK_SIZE, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ pkey_assert(sigstack.ss_sp != MAP_FAILED);
sigstack.ss_flags = 0;
sigstack.ss_size = STACK_SIZE;

@@ -488,6 +489,7 @@ static void test_pkru_sigreturn(void)
/* Set up alternate signal stack that will use the default MPK */
sigstack.ss_sp = mmap(0, STACK_SIZE, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ pkey_assert(sigstack.ss_sp != MAP_FAILED);
sigstack.ss_flags = 0;
sigstack.ss_size = STACK_SIZE;

diff --git a/tools/testing/selftests/mm/protection_keys.c b/tools/testing/selftests/mm/protection_keys.c
index be4a0470cc61..ae6e1530b354 100644
--- a/tools/testing/selftests/mm/protection_keys.c
+++ b/tools/testing/selftests/mm/protection_keys.c
@@ -582,7 +582,7 @@ static void *malloc_pkey_with_mprotect(long size, int prot, u16 pkey)
size, prot, pkey);
pkey_assert(pkey < NR_PKEYS);
ptr = mmap(NULL, size, prot, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
- pkey_assert(ptr != (void *)-1);
+ pkey_assert(ptr != MAP_FAILED);
ret = mprotect_pkey((void *)ptr, PAGE_SIZE, prot, pkey);
pkey_assert(!ret);
record_pkey_malloc(ptr, size, prot);
@@ -605,7 +605,7 @@ static void *malloc_pkey_anon_huge(long size, int prot, u16 pkey)
*/
size = ALIGN_UP(size, HPAGE_SIZE * 2);
ptr = mmap(NULL, size, PROT_NONE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
- pkey_assert(ptr != (void *)-1);
+ pkey_assert(ptr != MAP_FAILED);
record_pkey_malloc(ptr, size, prot);
mprotect_pkey(ptr, size, prot, pkey);

@@ -663,7 +663,7 @@ static void *malloc_pkey_hugetlb(long size, int prot, u16 pkey)
size = ALIGN_UP(size, HPAGE_SIZE * 2);
pkey_assert(pkey < NR_PKEYS);
ptr = mmap(NULL, size, PROT_NONE, flags, -1, 0);
- pkey_assert(ptr != (void *)-1);
+ pkey_assert(ptr != MAP_FAILED);
mprotect_pkey(ptr, size, prot, pkey);

record_pkey_malloc(ptr, size, prot);
@@ -692,7 +692,7 @@ static void *malloc_pkey(long size, int prot, u16 pkey)
pkey_assert(malloc_type < nr_malloc_types);

ret = pkey_malloc[malloc_type](size, prot, pkey);
- pkey_assert(ret != (void *)-1);
+ pkey_assert(ret != MAP_FAILED);

malloc_type++;
if (malloc_type >= nr_malloc_types)
@@ -1110,6 +1110,7 @@ static void arch_force_pkey_reg_init(void)
* doing the XSAVE size enumeration dance.
*/
buf = mmap(NULL, 1*MB, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
+ pkey_assert(buf != MAP_FAILED);

/* These __builtins require compiling with -mxsave */

@@ -1676,7 +1677,8 @@ int main(void)
ksft_print_msg("running PKEY tests for unsupported CPU/OS\n");

ptr = mmap(NULL, size, PROT_NONE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
- assert(ptr != (void *)-1);
+ if (ptr == MAP_FAILED)
+ ksft_exit_fail_perror("mmap");
test_mprotect_pkey_on_unsupported_cpu(ptr, 1);
ksft_test_result_pass("pkey on unsupported CPU/OS\n");
ksft_finished();
--
2.25.1