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selftests/mm: pagemap_ioctl: use the correct page size for transact_test()

PATCH Applied Zenghui Yu 2 participants 2 messages Jun 28

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Zenghui Yu

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#0 lore raw

PATCH 1/1 selftests/mm: pagemap_ioctl: use the correct page size for transact_test()

There are several places in transact_test() where we use the hardcoded 0x1000 (4k) as page size, which is not always correct for architectures supporting multiple page sizes.

Switch to use the correct page size. Otherwise ./ksft_pagemap.sh on a 16k-page-size arm64 box fails with

 $ ./ksft_pagemap.sh
 [...]
 # ok 96 mprotect_tests Both pages written after remap and mprotect
 # ok 97 mprotect_tests Clear and make the pages written
 # Bail out! ioctl failed
 # # Planned tests != run tests (117 != 97)
 # # Totals: pass:97 fail:0 xfail:0 xpass:0 skip:0 error:0
 # [FAIL]
 not ok 1 pagemap_ioctl # exit=1
 # SUMMARY: PASS=0 SKIP=0 FAIL=1
 1..1
Fixes 46fd75d4a3c9 ("selftests: mm: add pagemap ioctl tests")
Signed-off-by Zenghui Yu <[email protected]>
---
 tools/testing/selftests/mm/pagemap_ioctl.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)
tools/testing/selftests/mm/pagemap_ioctl.c +6 -6
index 762306177ad8..6f8971d5b3ce 100644
@@ -1368,7 +1368,7 @@ void *thread_proc(void *mem)
 			ksft_exit_fail_msg("pthread_barrier_wait\n");
 
 		for (i = 0; i < access_per_thread; ++i)
-			__atomic_add_fetch(m + i * (0x1000 / sizeof(*m)), 1, __ATOMIC_SEQ_CST);
+			__atomic_add_fetch(m + i * (page_size / sizeof(*m)), 1, __ATOMIC_SEQ_CST);
 
 		ret = pthread_barrier_wait(&end_barrier);
 		if (ret && ret != PTHREAD_BARRIER_SERIAL_THREAD)

@@ -1403,15 +1403,15 @@ static void transact_test(int page_size)
 	if (pthread_barrier_init(&end_barrier, NULL, nthreads + 1))
 		ksft_exit_fail_msg("pthread_barrier_init\n");
 
-	mem = mmap(NULL, 0x1000 * nthreads * pages_per_thread, PROT_READ | PROT_WRITE,
+	mem = mmap(NULL, page_size * nthreads * pages_per_thread, PROT_READ | PROT_WRITE,
 		   MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 	if (mem == MAP_FAILED)
 		ksft_exit_fail_msg("Error mmap %s.\n", strerror(errno));
 
-	wp_init(mem, 0x1000 * nthreads * pages_per_thread);
-	wp_addr_range(mem, 0x1000 * nthreads * pages_per_thread);
+	wp_init(mem, page_size * nthreads * pages_per_thread);
+	wp_addr_range(mem, page_size * nthreads * pages_per_thread);
 
-	memset(mem, 0, 0x1000 * nthreads * pages_per_thread);
+	memset(mem, 0, page_size * nthreads * pages_per_thread);
 
 	count = get_dirty_pages_reset(mem, nthreads * pages_per_thread, 1, page_size);
 	ksft_test_result(count > 0, "%s count %u\n", __func__, count);

@@ -1420,7 +1420,7 @@ static void transact_test(int page_size)
 
 	finish = 0;
 	for (i = 0; i < nthreads; ++i)
-		pthread_create(&th, NULL, thread_proc, mem + 0x1000 * i * pages_per_thread);
+		pthread_create(&th, NULL, thread_proc, mem + page_size * i * pages_per_thread);
 
 	extra_pages = 0;
 	for (i = 0; i < iter_count; ++i) {
Signature · 1 line
2.53.0
maintainer
#1 lore raw
Quoted 3 lines · On Sun, 28 Jun 2026 18:11:18 +0800 Zenghui Yu <[email protected]> wrote:

There are several places in transact_test() where we use the hardcoded 0x1000 (4k) as page size, which is not always correct for architectures supporting multiple page sizes.

doh.

Quoted 14 lines

Switch to use the correct page size. Otherwise ./ksft_pagemap.sh on a 16k-page-size arm64 box fails with

 $ ./ksft_pagemap.sh
 [...]
 # ok 96 mprotect_tests Both pages written after remap and mprotect
 # ok 97 mprotect_tests Clear and make the pages written
 # Bail out! ioctl failed
 # # Planned tests != run tests (117 != 97)
 # # Totals: pass:97 fail:0 xfail:0 xpass:0 skip:0 error:0
 # [FAIL]
 not ok 1 pagemap_ioctl # exit=1
 # SUMMARY: PASS=0 SKIP=0 FAIL=1
 1..1

Thanks. I'll add a cc:stable to this.

Quoted 2 lines
 tools/testing/selftests/mm/pagemap_ioctl.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

I'd like to see this code initialize page_size and hpage_size before calling init_uffd(), hugetlb_setup_default(), etc. That won't fix anything but it's safer and saner to get these globals set up before doing other things.