diff options
3 files changed, 248 insertions, 1 deletions
diff --git a/tools/testing/selftests/coredump/coredump_socket_protocol_test.c b/tools/testing/selftests/coredump/coredump_socket_protocol_test.c index f33eaf2fa93d..daff908232a2 100644 --- a/tools/testing/selftests/coredump/coredump_socket_protocol_test.c +++ b/tools/testing/selftests/coredump/coredump_socket_protocol_test.c @@ -2136,4 +2136,188 @@ TEST_F(coredump, socket_request_sparse_without_records) check_conflicting_ack(_metadata, self, COREDUMP_KERNEL | COREDUMP_SPARSE); } +/* What the server reports back about the coredump it decided to take. */ +struct stream_choice { + bool sparse; + ssize_t received; + off_t size; + ssize_t vm_size; +}; + +/* + * The kernel blocks in the coredump request until the ack arrives, so a + * coredump server gets to look at the task before it commits to a + * stream. Take the record stream only for a task whose mappings are + * worth it and the plain byte stream for everything else. + */ +static void check_stream_choice(struct __test_metadata *const _metadata, + FIXTURE_DATA(coredump) *self, bool big, + struct stream_choice *choice) +{ + int pidfd, status; + pid_t pid, pid_coredump_server; + struct pidfd_info info = {}; + int ipc_sockets[2]; + int pipefds[2]; + char c; + + ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets), 0); + ASSERT_EQ(pipe(pipefds), 0); + ASSERT_TRUE(set_core_pattern("@@/tmp/coredump.socket")); + + pid_coredump_server = fork(); + ASSERT_GE(pid_coredump_server, 0); + if (pid_coredump_server == 0) { + int fd_server = -1, fd_coredump = -1, fd_peer_pidfd = -1; + int fd_file = -1; + int exit_code = EXIT_FAILURE; + struct coredump_req req = {}; + struct stream_choice got = {}; + __u64 mask; + + close(ipc_sockets[0]); + close(pipefds[0]); + + fd_server = create_and_listen_unix_socket("/tmp/coredump.socket"); + if (fd_server < 0) + goto out; + + if (write_nointr(ipc_sockets[1], "1", 1) < 0) + goto out; + + close(ipc_sockets[1]); + + fd_coredump = accept4(fd_server, NULL, NULL, SOCK_CLOEXEC); + if (fd_coredump < 0) + goto out; + + fd_peer_pidfd = get_peer_pidfd(fd_coredump); + if (fd_peer_pidfd < 0) + goto out; + + /* + * The reassembled coredump is bigger than the mapping the + * child made, so keep it on the detached tmpfs and sparse. + */ + fd_file = open_coredump_tmpfile(self->fd_tmpfs_detached); + if (fd_file < 0) + goto out; + + if (!read_coredump_req(fd_coredump, &req)) + goto out; + + if (!check_coredump_req(&req)) + goto out; + + /* + * Nothing is on the wire yet and the kernel is waiting for + * the ack, so there is all the time in the world to look at + * the task and decide what to ask it for. + */ + got.vm_size = peer_vm_size(fd_peer_pidfd); + if (got.vm_size < 0) + goto out; + got.sparse = got.vm_size >= SPARSE_STREAM_THRESHOLD; + + fprintf(stderr, "Peer maps %zd bytes, asking for %s\n", + got.vm_size, + got.sparse ? "a sparse record stream" : "a byte stream"); + + mask = COREDUMP_KERNEL | COREDUMP_WAIT; + if (got.sparse) + mask |= COREDUMP_RECORDS | COREDUMP_SPARSE; + + if (!send_coredump_ack(fd_coredump, &req, mask, 0)) + goto out; + + if (!read_marker(fd_coredump, COREDUMP_MARK_REQACK)) + goto out; + + if (got.sparse) { + got.received = recv_coredump_records(fd_coredump, fd_file, + &got.size, NULL, -1); + } else { + got.received = recv_coredump_bytes(fd_coredump, fd_file); + got.size = got.received; + } + if (got.received < 0) + goto out; + + /* Either way a debugger has to see an ordinary core file. */ + if (!is_elf_core(fd_file)) + goto out; + + if (write_nointr(pipefds[1], &got, sizeof(got)) != sizeof(got)) + goto out; + + exit_code = EXIT_SUCCESS; +out: + close(pipefds[1]); + if (fd_file >= 0) + close(fd_file); + if (fd_peer_pidfd >= 0) + close(fd_peer_pidfd); + if (fd_coredump >= 0) + close(fd_coredump); + if (fd_server >= 0) + close(fd_server); + _exit(exit_code); + } + self->pid_coredump_server = pid_coredump_server; + + EXPECT_EQ(close(ipc_sockets[1]), 0); + EXPECT_EQ(close(pipefds[1]), 0); + ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1); + EXPECT_EQ(close(ipc_sockets[0]), 0); + + pid = fork(); + ASSERT_GE(pid, 0); + if (pid == 0) + crashing_child_sparse(big ? SPARSE_MAPPING_SIZE : PAGE_SIZE); + + pidfd = sys_pidfd_open(pid, 0); + ASSERT_GE(pidfd, 0); + + waitpid(pid, &status, 0); + ASSERT_TRUE(WIFSIGNALED(status)); + ASSERT_TRUE(WCOREDUMP(status)); + + ASSERT_EQ(read_nointr(pipefds[0], choice, sizeof(*choice)), + sizeof(*choice)); + EXPECT_EQ(close(pipefds[0]), 0); + + ASSERT_TRUE(get_pidfd_info(pidfd, &info)); + ASSERT_GT((info.mask & PIDFD_INFO_COREDUMP), 0); + ASSERT_GT((info.coredump_mask & PIDFD_COREDUMPED), 0); + + wait_and_check_coredump_server(pid_coredump_server, _metadata, self); +} + +/* A task with little mapped isn't worth a record stream. */ +TEST_F(coredump, socket_request_stream_choice_small) +{ + struct stream_choice choice = {}; + + check_stream_choice(_metadata, self, false, &choice); + + ASSERT_LT(choice.vm_size, (ssize_t)SPARSE_STREAM_THRESHOLD); + ASSERT_FALSE(choice.sparse); + ASSERT_GT(choice.received, 0); +} + +/* A task sitting on a big mapping is. */ +TEST_F(coredump, socket_request_stream_choice_large) +{ + struct stream_choice choice = {}; + + check_stream_choice(_metadata, self, true, &choice); + + ASSERT_GE(choice.vm_size, (ssize_t)SPARSE_STREAM_THRESHOLD); + ASSERT_TRUE(choice.sparse); + ASSERT_GT(choice.size, (off_t)SPARSE_MAPPING_SIZE); + + /* The holes didn't have to go over the socket. */ + ASSERT_LT(choice.received, choice.size / 8); +} + TEST_HARNESS_MAIN diff --git a/tools/testing/selftests/coredump/coredump_test_helpers.c b/tools/testing/selftests/coredump/coredump_test_helpers.c index 9346b8f688e2..d7cc448eeaf4 100644 --- a/tools/testing/selftests/coredump/coredump_test_helpers.c +++ b/tools/testing/selftests/coredump/coredump_test_helpers.c @@ -1095,6 +1095,33 @@ out: return ret; } +/* Read a plain coredump byte stream to end-of-file. */ +ssize_t recv_coredump_bytes(int fd_coredump, int fd_core_file) +{ + ssize_t received = 0; + + for (;;) { + char buffer[PAGE_SIZE]; + ssize_t ret = read_nointr(fd_coredump, buffer, sizeof(buffer)); + + if (ret < 0) { + fprintf(stderr, "%s: read failed: %m\n", __func__); + return -1; + } + if (ret == 0) + break; + + if (write_nointr(fd_core_file, buffer, ret) != ret) { + fprintf(stderr, "%s: write failed: %m\n", __func__); + return -1; + } + received += ret; + } + + fprintf(stderr, "Received %zd bytes of coredump\n", received); + return received; +} + int create_detached_tmpfs(void) { int fd_context, fd_tmpfs; @@ -1190,6 +1217,37 @@ bool get_pidfd_info(int fd_peer_pidfd, struct pidfd_info *info) return true; } +/* + * How much the peer has mapped. The task is parked in the coredump + * handshake, so its mm is still there to be looked at. + */ +ssize_t peer_vm_size(int fd_peer_pidfd) +{ + struct pidfd_info info = {}; + unsigned long pages; + char path[64]; + FILE *f; + + if (!get_pidfd_info(fd_peer_pidfd, &info)) + return -1; + + snprintf(path, sizeof(path), "/proc/%d/statm", info.pid); + f = fopen(path, "r"); + if (!f) { + fprintf(stderr, "%s: %s: %m\n", __func__, path); + return -1; + } + + if (fscanf(f, "%lu", &pages) != 1) { + fprintf(stderr, "%s: %s: no size\n", __func__, path); + fclose(f); + return -1; + } + fclose(f); + + return (ssize_t)pages * sysconf(_SC_PAGESIZE); +} + /* Protocol helper functions */ ssize_t recv_marker(int fd) diff --git a/tools/testing/selftests/coredump/coredump_test_helpers.h b/tools/testing/selftests/coredump/coredump_test_helpers.h index 00d695b67b3f..97ad5cfeae92 100644 --- a/tools/testing/selftests/coredump/coredump_test_helpers.h +++ b/tools/testing/selftests/coredump/coredump_test_helpers.h @@ -18,6 +18,9 @@ /* Size of the mostly unpopulated mapping the sparse coredump test maps. */ #define SPARSE_MAPPING_SIZE (256 * 1024 * 1024) +/* A task mapping at least this much is worth a record stream. */ +#define SPARSE_STREAM_THRESHOLD (SPARSE_MAPPING_SIZE / 2) + /* Shared helper function declarations */ void *do_nothing(void *arg); void crashing_child(void); @@ -25,9 +28,11 @@ void crashing_child_sparse(size_t size); ssize_t recv_coredump_records(int fd_coredump, int fd_core_file, off_t *coredump_size, bool *truncated, int fd_peer_pidfd); -bool is_elf_core(int fd); ssize_t recv_coredump_compact(int fd_coredump, int fd_object, int fd_reference, off_t *coredump_size); +ssize_t recv_coredump_bytes(int fd_coredump, int fd_core_file); +ssize_t peer_vm_size(int fd_peer_pidfd); +bool is_elf_core(int fd); int check_compact_coredump(int fd_object, int fd_reference); int create_detached_tmpfs(void); int create_and_listen_unix_socket(const char *path); |