From: Alban Crequy <[email protected]> Add selftests for the PROCESS_VM_PIDFD and PROCESS_VM_NOWAIT flags introduced in process_vm_readv/writev.
Tests cover: - basic read with no flags - invalid flags (EINVAL) - invalid address (EFAULT) - flag validation precedence over address validation - invalid pidfd (EBADF) - invalid pid (ESRCH) - PROCESS_VM_PIDFD: read via pidfd - PROCESS_VM_NOWAIT: read from resident memory - PROCESS_VM_PIDFD | PROCESS_VM_NOWAIT combined - userfaultfd blocking read (no flags) - PROCESS_VM_NOWAIT with userfaultfd (non-blocking, returns EFAULT) Signed-off-by: Alban Crequy <[email protected]> --- v3: - Add selftest for invalid pidfd (David Hildenbrand) - Add selftest for invalid pid - SKIP on kernels without PROCESS_VM_PIDFD support - Remove hardcoded __NR_pidfd_open fallback, use <sys/syscall.h> (Sashiko) - SKIP pidfd tests on kernels without pidfd_open (ENOSYS) (Sashiko) - SKIP userfaultfd tests when unprivileged userfaultfd is disabled (EPERM) (Sashiko) - Fault in test_data before NOWAIT tests to ensure page is resident (Sashiko) - Add ksft_process_vm_readv.sh wrapper and run_vmtests.sh entry v2: - New patch. tools/testing/selftests/mm/Makefile | 2 + .../selftests/mm/ksft_process_vm_readv.sh | 4 + tools/testing/selftests/mm/process_vm_readv.c | 421 ++++++++++++++++++ tools/testing/selftests/mm/run_vmtests.sh | 4 + 4 files changed, 431 insertions(+) create mode 100755 tools/testing/selftests/mm/ksft_process_vm_readv.sh create mode 100644 tools/testing/selftests/mm/process_vm_readv.c diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile index cd24596cdd27..feb3a0b9a57e 100644 --- a/tools/testing/selftests/mm/Makefile +++ b/tools/testing/selftests/mm/Makefile @@ -106,6 +106,7 @@ TEST_GEN_FILES += guard-regions TEST_GEN_FILES += merge TEST_GEN_FILES += rmap TEST_GEN_FILES += folio_split_race_test +TEST_GEN_FILES += process_vm_readv ifneq ($(ARCH),arm64) TEST_GEN_FILES += soft-dirty @@ -167,6 +168,7 @@ TEST_PROGS += ksft_pfnmap.sh TEST_PROGS += ksft_pkey.sh TEST_PROGS += ksft_process_madv.sh TEST_PROGS += ksft_process_mrelease.sh +TEST_PROGS += ksft_process_vm_readv.sh TEST_PROGS += ksft_rmap.sh TEST_PROGS += ksft_soft_dirty.sh TEST_PROGS += ksft_thp.sh diff --git a/tools/testing/selftests/mm/ksft_process_vm_readv.sh b/tools/testing/selftests/mm/ksft_process_vm_readv.sh new file mode 100755 index 000000000000..09d0fcc9a35d --- /dev/null +++ b/tools/testing/selftests/mm/ksft_process_vm_readv.sh @@ -0,0 +1,4 @@ +#!/bin/sh -e +# SPDX-License-Identifier: GPL-2.0 + +./run_vmtests.sh -t process_vm_readv diff --git a/tools/testing/selftests/mm/process_vm_readv.c b/tools/testing/selftests/mm/process_vm_readv.c new file mode 100644 index 000000000000..0479ae424c78 --- /dev/null +++ b/tools/testing/selftests/mm/process_vm_readv.c @@ -0,0 +1,421 @@ +// SPDX-License-Identifier: GPL-2.0-only +#define _GNU_SOURCE +#include <errno.h> +#include <fcntl.h> +#include <poll.h> +#include <pthread.h> +#include <signal.h> +#include <stdbool.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/ioctl.h> +#include <sys/mman.h> +#include <sys/syscall.h> +#include <sys/uio.h> +#include <sys/wait.h> +#include <unistd.h> +#include <linux/userfaultfd.h> + +#include "kselftest_harness.h" + +#ifndef PROCESS_VM_PIDFD +#define PROCESS_VM_PIDFD (1UL << 0) +#endif + +#ifndef PROCESS_VM_NOWAIT +#define PROCESS_VM_NOWAIT (1UL << 1) +#endif + +static int sys_pidfd_open(pid_t pid, unsigned int flags) +{ + return syscall(__NR_pidfd_open, pid, flags); +} + +static const uint8_t test_data[] = { 0x01, 0x02, 0x03, 0x04, + 0x05, 0x06, 0x07, 0x08 }; +#define POISON_BYTE 0xCC + +/* + * Test: basic process_vm_readv with no flags + */ +TEST(read_basic) +{ + uint8_t buf[sizeof(test_data)]; + struct iovec local_iov = { .iov_base = buf, .iov_len = sizeof(buf) }; + struct iovec remote_iov = { + .iov_base = (void *)test_data, + .iov_len = sizeof(test_data) + }; + ssize_t n; + + memset(buf, POISON_BYTE, sizeof(buf)); + n = process_vm_readv(getpid(), &local_iov, 1, &remote_iov, 1, 0); + ASSERT_EQ(sizeof(test_data), n); + ASSERT_EQ(0, memcmp(buf, test_data, sizeof(test_data))); +} + +/* + * Test: invalid flags should return EINVAL + */ +TEST(read_invalid_flags) +{ + uint8_t buf[8] = { 0 }; + struct iovec local_iov = { .iov_base = buf, .iov_len = sizeof(buf) }; + struct iovec remote_iov = { + .iov_base = (void *)test_data, + .iov_len = sizeof(test_data) + }; + ssize_t n; + + n = process_vm_readv(getpid(), &local_iov, 1, &remote_iov, 1, 255); + ASSERT_EQ(-1, n); + ASSERT_EQ(EINVAL, errno); +} + +/* + * Test: invalid address should return EFAULT + */ +TEST(read_invalid_address) +{ + uint8_t buf[8] = { 0 }; + struct iovec local_iov = { .iov_base = buf, .iov_len = sizeof(buf) }; + struct iovec remote_iov = { .iov_base = NULL, .iov_len = 8 }; + ssize_t n; + + n = process_vm_readv(getpid(), &local_iov, 1, &remote_iov, 1, 0); + ASSERT_EQ(-1, n); + ASSERT_EQ(EFAULT, errno); +} + +/* + * Test: invalid address with invalid flags should return EINVAL + * (flag check happens before address validation) + */ +TEST(read_invalid_address_invalid_flags) +{ + uint8_t buf[8] = { 0 }; + struct iovec local_iov = { .iov_base = buf, .iov_len = sizeof(buf) }; + struct iovec remote_iov = { .iov_base = NULL, .iov_len = 8 }; + ssize_t n; + + n = process_vm_readv(getpid(), &local_iov, 1, &remote_iov, 1, 255); + ASSERT_EQ(-1, n); + ASSERT_EQ(EINVAL, errno); +} + +/* + * Test: invalid address with all valid flags should return EFAULT + * (flags are valid so we get past the flag check to the address check) + */ +TEST(read_invalid_address_all_valid_flags) +{ + int pidfd; + struct iovec local_iov = { .iov_base = NULL, .iov_len = 8 }; + struct iovec remote_iov = { .iov_base = NULL, .iov_len = 8 }; + ssize_t n; + + pidfd = sys_pidfd_open(getpid(), 0); + if (pidfd < 0 && errno == ENOSYS) + SKIP(return, "pidfd_open not supported"); + ASSERT_GE(pidfd, 0); + + n = process_vm_readv(pidfd, &local_iov, 1, &remote_iov, 1, + PROCESS_VM_PIDFD | PROCESS_VM_NOWAIT); + ASSERT_EQ(-1, n); + ASSERT_EQ(EFAULT, errno); + + close(pidfd); +} + +/* + * Test: read with an invalid pidfd should return an error, not crash + */ +TEST(read_invalid_pidfd) +{ + uint8_t buf[sizeof(test_data)] = { 0 }; + struct iovec local_iov = { .iov_base = buf, .iov_len = sizeof(buf) }; + struct iovec remote_iov = { + .iov_base = (void *)test_data, + .iov_len = sizeof(test_data) + }; + ssize_t n; + + /* fd 9999 is almost certainly not a valid pidfd */ + n = process_vm_readv(9999, &local_iov, 1, &remote_iov, 1, + PROCESS_VM_PIDFD); + ASSERT_EQ(-1, n); + if (errno == EINVAL) + SKIP(return, "PROCESS_VM_PIDFD not supported"); + ASSERT_EQ(EBADF, errno); +} + +/* + * Test: read with an invalid pid should return ESRCH + */ +TEST(read_invalid_pid) +{ + uint8_t buf[sizeof(test_data)] = { 0 }; + struct iovec local_iov = { .iov_base = buf, .iov_len = sizeof(buf) }; + struct iovec remote_iov = { + .iov_base = (void *)test_data, + .iov_len = sizeof(test_data) + }; + ssize_t n; + + /* pid 999999 is almost certainly not a valid process */ + n = process_vm_readv(999999, &local_iov, 1, &remote_iov, 1, 0); + ASSERT_EQ(-1, n); + ASSERT_EQ(ESRCH, errno); +} + +/* + * Test: read with PIDFD flag + */ +TEST(read_pidfd) +{ + uint8_t buf[sizeof(test_data)]; + struct iovec local_iov = { .iov_base = buf, .iov_len = sizeof(buf) }; + struct iovec remote_iov = { + .iov_base = (void *)test_data, + .iov_len = sizeof(test_data) + }; + ssize_t n; + int pidfd; + + memset(buf, POISON_BYTE, sizeof(buf)); + pidfd = sys_pidfd_open(getpid(), 0); + if (pidfd < 0 && errno == ENOSYS) + SKIP(return, "pidfd_open not supported"); + ASSERT_GE(pidfd, 0); + + n = process_vm_readv(pidfd, &local_iov, 1, &remote_iov, 1, + PROCESS_VM_PIDFD); + ASSERT_EQ(sizeof(test_data), n); + ASSERT_EQ(0, memcmp(buf, test_data, sizeof(test_data))); + + close(pidfd); +} + +/* + * Test: read with NOWAIT from resident memory (should succeed) + */ +TEST(read_nowait_resident) +{ + uint8_t buf[sizeof(test_data)]; + struct iovec local_iov = { .iov_base = buf, .iov_len = sizeof(buf) }; + struct iovec remote_iov = { + .iov_base = (void *)test_data, + .iov_len = sizeof(test_data) + }; + ssize_t n; + + *(volatile uint64_t *)test_data; /* fault in page for NOWAIT */ + memset(buf, POISON_BYTE, sizeof(buf)); + n = process_vm_readv(getpid(), &local_iov, 1, &remote_iov, 1, + PROCESS_VM_NOWAIT); + ASSERT_EQ(sizeof(test_data), n); + ASSERT_EQ(0, memcmp(buf, test_data, sizeof(test_data))); +} + +/* + * Test: read with PIDFD + NOWAIT from resident memory + */ +TEST(read_pidfd_nowait_resident) +{ + uint8_t buf[sizeof(test_data)]; + struct iovec local_iov = { .iov_base = buf, .iov_len = sizeof(buf) }; + struct iovec remote_iov = { + .iov_base = (void *)test_data, + .iov_len = sizeof(test_data) + }; + ssize_t n; + int pidfd; + + *(volatile uint64_t *)test_data; /* fault in page for NOWAIT */ + memset(buf, POISON_BYTE, sizeof(buf)); + pidfd = sys_pidfd_open(getpid(), 0); + if (pidfd < 0 && errno == ENOSYS) + SKIP(return, "pidfd_open not supported"); + ASSERT_GE(pidfd, 0); + + n = process_vm_readv(pidfd, &local_iov, 1, &remote_iov, 1, + PROCESS_VM_PIDFD | PROCESS_VM_NOWAIT); + ASSERT_EQ(sizeof(test_data), n); + ASSERT_EQ(0, memcmp(buf, test_data, sizeof(test_data))); + + close(pidfd); +} + +/* + * Userfaultfd helpers for NOWAIT tests + */ +static int setup_userfaultfd(void) +{ + struct uffdio_api api = { .api = UFFD_API }; + int uffd; + + uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK); + if (uffd < 0) + return -errno; + + if (ioctl(uffd, UFFDIO_API, &api)) { + close(uffd); + return -errno; + } + + return uffd; +} + +static void *register_uffd_region(int uffd, size_t size) +{ + struct uffdio_register reg; + void *mem; + + mem = mmap(NULL, size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (mem == MAP_FAILED) + return NULL; + + reg.range.start = (unsigned long)mem; + reg.range.len = size; + reg.mode = UFFDIO_REGISTER_MODE_MISSING; + if (ioctl(uffd, UFFDIO_REGISTER, ®)) { + munmap(mem, size); + return NULL; + } + + return mem; +} + +struct uffd_handler_args { + int uffd; + const void *content; + size_t content_len; +}; + +static void *uffd_handler_thread(void *arg) +{ + struct uffd_handler_args *ha = arg; + struct uffd_msg msg; + struct uffdio_copy uffd_copy; + struct pollfd pfd = { + .fd = ha->uffd, + .events = POLLIN + }; + void *page; + long page_size = sysconf(_SC_PAGESIZE); + int ret; + + page = mmap(NULL, page_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (page == MAP_FAILED) + return (void *)(long)-ENOMEM; + + memcpy(page, ha->content, ha->content_len); + + ret = poll(&pfd, 1, 5000); + if (ret <= 0) + goto out; + + if (read(ha->uffd, &msg, sizeof(msg)) != sizeof(msg)) + goto out; + + if (msg.event != UFFD_EVENT_PAGEFAULT) + goto out; + + uffd_copy.dst = msg.arg.pagefault.address & ~(page_size - 1); + uffd_copy.src = (unsigned long)page; + uffd_copy.len = page_size; + uffd_copy.mode = 0; + ioctl(ha->uffd, UFFDIO_COPY, &uffd_copy); + +out: + munmap(page, page_size); + return NULL; +} + +/* + * Test: read from userfaultfd-registered memory (no flags, should block + * until page fault is resolved by handler thread) + */ +TEST(read_userfaultfd_blocking) +{ + int uffd; + void *mem; + long page_size = sysconf(_SC_PAGESIZE); + uint8_t buf[sizeof(test_data)]; + struct iovec local_iov = { .iov_base = buf, .iov_len = sizeof(buf) }; + struct iovec remote_iov; + struct uffd_handler_args ha; + pthread_t handler; + ssize_t n; + + memset(buf, POISON_BYTE, sizeof(buf)); + + uffd = setup_userfaultfd(); + if (uffd == -EPERM) + SKIP(return, "userfaultfd requires privileges (vm.unprivileged_userfaultfd=0)"); + if (uffd == -ENOSYS) + SKIP(return, "userfaultfd not supported"); + ASSERT_GE(uffd, 0); + + mem = register_uffd_region(uffd, page_size); + ASSERT_NE(NULL, mem); + + ha.uffd = uffd; + ha.content = test_data; + ha.content_len = sizeof(test_data); + ASSERT_EQ(0, pthread_create(&handler, NULL, uffd_handler_thread, &ha)); + + remote_iov.iov_base = mem; + remote_iov.iov_len = sizeof(test_data); + n = process_vm_readv(getpid(), &local_iov, 1, &remote_iov, 1, 0); + ASSERT_EQ(sizeof(test_data), n); + ASSERT_EQ(0, memcmp(buf, test_data, sizeof(test_data))); + + pthread_join(handler, NULL); + munmap(mem, page_size); + close(uffd); +} + +/* + * Test: read with NOWAIT from userfaultfd-registered memory that has + * not been faulted in yet. Should return EFAULT (not block). + */ +TEST(read_nowait_userfaultfd) +{ + int uffd; + void *mem; + long page_size = sysconf(_SC_PAGESIZE); + uint8_t buf[sizeof(test_data)] = { 0 }; + struct iovec local_iov = { .iov_base = buf, .iov_len = sizeof(buf) }; + struct iovec remote_iov; + ssize_t n; + + uffd = setup_userfaultfd(); + if (uffd == -EPERM) + SKIP(return, "userfaultfd requires privileges (vm.unprivileged_userfaultfd=0)"); + if (uffd == -ENOSYS) + SKIP(return, "userfaultfd not supported"); + ASSERT_GE(uffd, 0); + + mem = register_uffd_region(uffd, page_size); + ASSERT_NE(NULL, mem); + + /* Ensure the page is not present */ + madvise(mem, page_size, MADV_DONTNEED); + + remote_iov.iov_base = mem; + remote_iov.iov_len = sizeof(test_data); + n = process_vm_readv(getpid(), &local_iov, 1, &remote_iov, 1, + PROCESS_VM_NOWAIT); + ASSERT_EQ(-1, n); + ASSERT_EQ(EFAULT, errno); + + munmap(mem, page_size); + close(uffd); +} + +TEST_HARNESS_MAIN diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh index d8468451b3a3..7d30f6101088 100755 --- a/tools/testing/selftests/mm/run_vmtests.sh +++ b/tools/testing/selftests/mm/run_vmtests.sh @@ -91,6 +91,8 @@ separated by spaces: test VMA merge cases behave as expected - rmap test rmap behaves as expected +- process_vm_readv + test process_vm_readv flags (pidfd, nowait) - memory-failure test memory-failure behaves as expected @@ -531,6 +533,8 @@ CATEGORY="page_frag" run_test ./test_page_frag.sh nonaligned CATEGORY="rmap" run_test ./rmap +CATEGORY="process_vm_readv" run_test ./process_vm_readv + # Try to load hwpoison_inject if not present. HWPOISON_DIR=/sys/kernel/debug/hwpoison/ if [ ! -d "$HWPOISON_DIR" ]; then -- 2.45.0
