On 2026/4/9 1:24, Lisa Wang wrote:
> Add a shmem memory failure selftest to test the shmem memory failure is
> correct after modifying shmem return value.
>
> Test that
> + madvise() call returns 0 when the poisoned shmem page is clean
> + trigger a SIGBUS when the poisoned shmem page is dirty
> + trigger another SIGBUS when the poisoned shmem page is fault-in again.
>
> Signed-off-by: Lisa Wang <[email protected]>
Thanks for your patch. Two questions below.
> ---
> tools/testing/selftests/mm/memory-failure.c | 109
> +++++++++++++++++++++++++++-
> 1 file changed, 106 insertions(+), 3 deletions(-)
>
> diff --git a/tools/testing/selftests/mm/memory-failure.c
> b/tools/testing/selftests/mm/memory-failure.c
> index 3d9e0b9ffb41..eb3f8d98f6c9 100644
> --- a/tools/testing/selftests/mm/memory-failure.c
> +++ b/tools/testing/selftests/mm/memory-failure.c
> @@ -30,9 +30,14 @@ enum result_type {
> MADV_HARD_ANON,
> MADV_HARD_CLEAN_PAGECACHE,
> MADV_HARD_DIRTY_PAGECACHE,
> + MADV_HARD_CLEAN_SHMEM,
> + MADV_HARD_DIRTY_SHMEM,
> MADV_SOFT_ANON,
> MADV_SOFT_CLEAN_PAGECACHE,
> MADV_SOFT_DIRTY_PAGECACHE,
> + MADV_SOFT_CLEAN_SHMEM,
> + MADV_SOFT_DIRTY_SHMEM,
> + READ_ERROR,
> };
>
> static jmp_buf signal_jmp_buf;
> @@ -165,17 +170,21 @@ static void check(struct __test_metadata *_metadata,
> FIXTURE_DATA(memory_failure
> 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);
> -
> + case MADV_SOFT_DIRTY_SHMEM:
> /* The page content should remain unchanged. */
> ASSERT_TRUE(check_memory(vaddr, self->page_size));
Why we skip check_memory() for case MADV_SOFT_CLEAN_SHMEM?
> + case MADV_HARD_CLEAN_SHMEM:
> + case MADV_SOFT_CLEAN_SHMEM:
> + /* It is not expected to receive a SIGBUS signal. */
> + ASSERT_EQ(setjmp, 0);
>
> /* The backing pfn of addr should have changed. */
> ASSERT_NE(pagemap_get_pfn(self->pagemap_fd, vaddr), self->pfn);
> break;
> case MADV_HARD_ANON:
> case MADV_HARD_DIRTY_PAGECACHE:
> + case MADV_HARD_DIRTY_SHMEM:
> + case READ_ERROR:
> /* The SIGBUS signal should have been received. */
> ASSERT_EQ(setjmp, 1);
>
> @@ -260,6 +269,20 @@ static int prepare_file(const char *fname, unsigned long
> size)
> return fd;
> }
>
> +static int prepare_shmem(const char *fname, unsigned long size)
> +{
> + int fd;
> +
> + fd = memfd_create(fname, 0);
> + if (fd < 0)
> + return -1;
> + if (ftruncate(fd, size) < 0) {
> + close(fd);
> + return -1;
> + }
> + return fd;
> +}
> +
> /* Borrowed from mm/gup_longterm.c. */
> static int get_fs_type(int fd)
> {
> @@ -356,4 +379,84 @@ TEST_F(memory_failure, dirty_pagecache)
> ASSERT_EQ(close(fd), 0);
> }
>
> +TEST_F(memory_failure, dirty_shmem)
> +{
> + int fd;
> + char *addr;
> + int ret;
> +
> + fd = prepare_shmem("shmem-file", self->page_size);
> + if (fd < 0)
> + SKIP(return, "failed to open test shmem-file.\n");
> +
> + addr = mmap(0, self->page_size, PROT_READ | PROT_WRITE,
> + MAP_SHARED, fd, 0);
> + if (addr == MAP_FAILED) {
> + close(fd);
> + 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 (ret == 0)
> + ASSERT_EQ(variant->inject(self, addr), 0);
> +
> + if (variant->type == MADV_HARD) {
> + check(_metadata, self, addr, MADV_HARD_DIRTY_SHMEM, ret);
> + ret = sigsetjmp(signal_jmp_buf, 1);
> + if (ret == 0)
> + FORCE_READ(*addr);
> + check(_metadata, self, addr, READ_ERROR, ret);
> + } else {
Should we always add a FORCE_READ() just after variant->inject to verify the
accessibility
to the addr for soft-offline case ?
Thanks.
.
> + check(_metadata, self, addr, MADV_SOFT_DIRTY_SHMEM, ret);> +
> }
> +
> + ASSERT_EQ(munmap(addr, self->page_size), 0);
> +
> + ASSERT_EQ(close(fd), 0);
> + cleanup(_metadata, self, addr);
> +}
> +
> +TEST_F(memory_failure, clean_shmem)
> +{
> + int fd;
> + char *addr;
> + int ret;
> +
> + fd = prepare_shmem("shmem-file", self->page_size);
> + if (fd < 0)
> + SKIP(return, "failed to open test shmem-file.\n");
> +
> + addr = mmap(0, self->page_size, PROT_READ | PROT_WRITE,
> + MAP_SHARED, fd, 0);
> + if (addr == MAP_FAILED) {
> + close(fd);
> + SKIP(return, "mmap failed, not enough memory.\n");
> + }
> + FORCE_READ(*addr);
> +
> + prepare(_metadata, self, addr);
> +
> + ret = sigsetjmp(signal_jmp_buf, 1);
> + if (ret == 0)
> + ASSERT_EQ(variant->inject(self, addr), 0);
> +
> + if (variant->type == MADV_HARD) {
> + check(_metadata, self, addr, MADV_HARD_CLEAN_SHMEM, ret);
> + ret = sigsetjmp(signal_jmp_buf, 1);
> + if (ret == 0)
> + FORCE_READ(*addr);
> + check(_metadata, self, addr, READ_ERROR, ret);
> + } else {
> + check(_metadata, self, addr, MADV_SOFT_CLEAN_SHMEM, ret);
> + }
> +
> + ASSERT_EQ(munmap(addr, self->page_size), 0);
> +
> + ASSERT_EQ(close(fd), 0);
> + cleanup(_metadata, self, addr);
> +}
> +
> TEST_HARNESS_MAIN
>
