linux-kernel - [PATCH v2 3/3] selftests/mm: add memory failure dirty pagecache test

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Message-ID: <20260120123239.909882-4-linmiaohe@huawei.com>
Date: Tue, 20 Jan 2026 20:32:39 +0800
From: Miaohe Lin <linmiaohe@...wei.com>
To: <akpm@...ux-foundation.org>, <shuah@...nel.org>
CC: <david@...nel.org>, <lorenzo.stoakes@...cle.com>,
	<Liam.Howlett@...cle.com>, <vbabka@...e.cz>, <rppt@...nel.org>,
	<surenb@...gle.com>, <mhocko@...e.com>, <nao.horiguchi@...il.com>,
	<linmiaohe@...wei.com>, <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
	<linux-kselftest@...r.kernel.org>
Subject: [PATCH v2 3/3] 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.

Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
---
 tools/testing/selftests/mm/memory-failure.c | 62 +++++++++++++++++++--
 1 file changed, 58 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/mm/memory-failure.c b/tools/testing/selftests/mm/memory-failure.c
index 128c2ee6d332..a74a057599b4 100644
--- a/tools/testing/selftests/mm/memory-failure.c
+++ b/tools/testing/selftests/mm/memory-failure.c
@@ -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 __fsword_t get_fs_type(int fd)
 {
@@ -259,17 +275,14 @@ static __fsword_t 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;
 	__fsword_t 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 :%lx\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;
+	__fsword_t 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 :%lx\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
-- 
2.33.0