Commit d51b5076 authored by Miaohe Lin's avatar Miaohe Lin Committed by Andrew Morton
Browse files

selftests/mm: add memory failure dirty pagecache test 

This patch adds a new testcase to validate memory failure handling for
dirty pagecache.  This performs similar operations as clean pagecaches
except fsync() is not used to keep pages dirty.

This test helps ensure that memory failure handling for dirty pagecache
works correctly, including proper SIGBUS delivery, page isolation, and
recovery paths.

Link: https://lkml.kernel.org/r/20260206031639.2707102-4-linmiaohe@huawei.com


Signed-off-by: default avatarMiaohe Lin <linmiaohe@huawei.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: kernel test robot <lkp@intel.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 12e8a2fa

tools/testing/selftests/mm/memory-failure.c

+58 −4
Original line number Diff line number Diff line
@@ -29,8 +29,10 @@ enum inject_type { 
enum result_type {

	MADV_HARD_ANON,

	MADV_HARD_CLEAN_PAGECACHE,

	MADV_HARD_DIRTY_PAGECACHE,

	MADV_SOFT_ANON,

	MADV_SOFT_CLEAN_PAGECACHE,

	MADV_SOFT_DIRTY_PAGECACHE,

};



static jmp_buf signal_jmp_buf;
@@ -162,6 +164,7 @@ static void check(struct __test_metadata *_metadata, FIXTURE_DATA(memory_failure 
	case MADV_SOFT_ANON:

	case MADV_HARD_CLEAN_PAGECACHE:

	case MADV_SOFT_CLEAN_PAGECACHE:

	case MADV_SOFT_DIRTY_PAGECACHE:

		/* It is not expected to receive a SIGBUS signal. */

		ASSERT_EQ(setjmp, 0);
@@ -172,6 +175,7 @@ static void check(struct __test_metadata *_metadata, FIXTURE_DATA(memory_failure 
		ASSERT_NE(pagemap_get_pfn(self->pagemap_fd, vaddr), self->pfn);

		break;

	case MADV_HARD_ANON:

	case MADV_HARD_DIRTY_PAGECACHE:

		/* The SIGBUS signal should have been received. */

		ASSERT_EQ(setjmp, 1);
@@ -244,6 +248,18 @@ TEST_F(memory_failure, anon) 
	ASSERT_EQ(munmap(addr, self->page_size), 0);

}



static int prepare_file(const char *fname, unsigned long size)

{

	int fd;



	fd = open(fname, O_RDWR | O_CREAT, 0664);

	if (fd >= 0) {

		unlink(fname);

		ftruncate(fd, size);

	}

	return fd;

}



/* Borrowed from mm/gup_longterm.c. */

static int get_fs_type(int fd)

{
@@ -259,17 +275,14 @@ static int get_fs_type(int fd) 


TEST_F(memory_failure, clean_pagecache)

{

	const char *fname = "./clean-page-cache-test-file";

	int fd;

	char *addr;

	int ret;

	int fs_type;



	fd = open(fname, O_RDWR | O_CREAT, 0664);

	fd = prepare_file("./clean-page-cache-test-file", self->page_size);

	if (fd < 0)

		SKIP(return, "failed to open test file.\n");

	unlink(fname);

	ftruncate(fd, self->page_size);

	fs_type = get_fs_type(fd);

	if (!fs_type || fs_type == TMPFS_MAGIC)

		SKIP(return, "unsupported filesystem :%x\n", fs_type);
@@ -302,4 +315,45 @@ TEST_F(memory_failure, clean_pagecache) 
	ASSERT_EQ(close(fd), 0);

}



TEST_F(memory_failure, dirty_pagecache)

{

	int fd;

	char *addr;

	int ret;

	int fs_type;



	fd = prepare_file("./dirty-page-cache-test-file", self->page_size);

	if (fd < 0)

		SKIP(return, "failed to open test file.\n");

	fs_type = get_fs_type(fd);

	if (!fs_type || fs_type == TMPFS_MAGIC)

		SKIP(return, "unsupported filesystem :%x\n", fs_type);



	addr = mmap(0, self->page_size, PROT_READ | PROT_WRITE,

		    MAP_SHARED, fd, 0);

	if (addr == MAP_FAILED)

		SKIP(return, "mmap failed, not enough memory.\n");

	memset(addr, 0xce, self->page_size);



	prepare(_metadata, self, addr);



	ret = sigsetjmp(signal_jmp_buf, 1);

	if (!self->triggered) {

		self->triggered = true;

		ASSERT_EQ(variant->inject(self, addr), 0);

		FORCE_READ(*addr);

	}



	if (variant->type == MADV_HARD)

		check(_metadata, self, addr, MADV_HARD_DIRTY_PAGECACHE, ret);

	else

		check(_metadata, self, addr, MADV_SOFT_DIRTY_PAGECACHE, ret);



	cleanup(_metadata, self, addr);



	ASSERT_EQ(munmap(addr, self->page_size), 0);



	ASSERT_EQ(close(fd), 0);

}



TEST_HARNESS_MAIN