Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 954 insertions, 0 deletions

diff --git a/tools/testing/vsock/util.c b/tools/testing/vsock/util.c
new file mode 100644
index 000000000..fe316b02a
--- /dev/null
+++ b/tools/testing/vsock/util.c
@@ -0,0 +1,954 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * vsock test utilities
+ *
+ * Copyright (C) 2017 Red Hat, Inc.
+ *
+ * Author: Stefan Hajnoczi <stefanha@redhat.com>
+ */
+
+#include <ctype.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <signal.h>
+#include <unistd.h>
+#include <assert.h>
+#include <sys/epoll.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <linux/sockios.h>
+
+#include "timeout.h"
+#include "control.h"
+#include "util.h"
+
+#define KALLSYMS_PATH		"/proc/kallsyms"
+#define KALLSYMS_LINE_LEN	512
+
+/* Install signal handlers */
+void init_signals(void)
+{
+	struct sigaction act = {
+		.sa_handler = sigalrm,
+	};
+
+	sigaction(SIGALRM, &act, NULL);
+	signal(SIGPIPE, SIG_IGN);
+}
+
+static unsigned int parse_uint(const char *str, const char *err_str)
+{
+	char *endptr = NULL;
+	unsigned long n;
+
+	errno = 0;
+	n = strtoul(str, &endptr, 10);
+	if (errno || *endptr != '\0') {
+		fprintf(stderr, "malformed %s \"%s\"\n", err_str, str);
+		exit(EXIT_FAILURE);
+	}
+	return n;
+}
+
+/* Parse a CID in string representation */
+unsigned int parse_cid(const char *str)
+{
+	return parse_uint(str, "CID");
+}
+
+/* Parse a port in string representation */
+unsigned int parse_port(const char *str)
+{
+	return parse_uint(str, "port");
+}
+
+/* Wait for the remote to close the connection */
+void vsock_wait_remote_close(int fd)
+{
+	struct epoll_event ev;
+	int epollfd, nfds;
+
+	epollfd = epoll_create1(0);
+	if (epollfd == -1) {
+		perror("epoll_create1");
+		exit(EXIT_FAILURE);
+	}
+
+	ev.events = EPOLLRDHUP | EPOLLHUP;
+	ev.data.fd = fd;
+	if (epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev) == -1) {
+		perror("epoll_ctl");
+		exit(EXIT_FAILURE);
+	}
+
+	nfds = epoll_wait(epollfd, &ev, 1, TIMEOUT * 1000);
+	if (nfds == -1) {
+		perror("epoll_wait");
+		exit(EXIT_FAILURE);
+	}
+
+	if (nfds == 0) {
+		fprintf(stderr, "epoll_wait timed out\n");
+		exit(EXIT_FAILURE);
+	}
+
+	assert(nfds == 1);
+	assert(ev.events & (EPOLLRDHUP | EPOLLHUP));
+	assert(ev.data.fd == fd);
+
+	close(epollfd);
+}
+
+/* Wait until ioctl gives an expected int value.
+ * Return false if the op is not supported.
+ */
+bool vsock_ioctl_int(int fd, unsigned long op, int expected)
+{
+	int actual, ret;
+	char name[32];
+
+	snprintf(name, sizeof(name), "ioctl(%lu)", op);
+
+	timeout_begin(TIMEOUT);
+	do {
+		ret = ioctl(fd, op, &actual);
+		if (ret < 0) {
+			if (errno == EOPNOTSUPP || errno == ENOTTY)
+				break;
+
+			perror(name);
+			exit(EXIT_FAILURE);
+		}
+		timeout_check(name);
+	} while (actual != expected);
+	timeout_end();
+
+	return ret >= 0;
+}
+
+/* Wait until transport reports no data left to be sent.
+ * Return false if transport does not implement the unsent_bytes() callback.
+ */
+bool vsock_wait_sent(int fd)
+{
+	return vsock_ioctl_int(fd, SIOCOUTQ, 0);
+}
+
+/* Create socket <type>, bind to <cid, port>.
+ * Return the file descriptor, or -1 on error.
+ */
+int vsock_bind_try(unsigned int cid, unsigned int port, int type)
+{
+	struct sockaddr_vm sa = {
+		.svm_family = AF_VSOCK,
+		.svm_cid = cid,
+		.svm_port = port,
+	};
+	int fd, saved_errno;
+
+	fd = socket(AF_VSOCK, type, 0);
+	if (fd < 0) {
+		perror("socket");
+		exit(EXIT_FAILURE);
+	}
+
+	if (bind(fd, (struct sockaddr *)&sa, sizeof(sa))) {
+		saved_errno = errno;
+		close(fd);
+		errno = saved_errno;
+		fd = -1;
+	}
+
+	return fd;
+}
+
+/* Create socket <type>, bind to <cid, port> and return the file descriptor. */
+int vsock_bind(unsigned int cid, unsigned int port, int type)
+{
+	int fd;
+
+	fd = vsock_bind_try(cid, port, type);
+	if (fd < 0) {
+		perror("bind");
+		exit(EXIT_FAILURE);
+	}
+
+	return fd;
+}
+
+int vsock_connect_fd(int fd, unsigned int cid, unsigned int port)
+{
+	struct sockaddr_vm sa = {
+		.svm_family = AF_VSOCK,
+		.svm_cid = cid,
+		.svm_port = port,
+	};
+	int ret;
+
+	timeout_begin(TIMEOUT);
+	do {
+		ret = connect(fd, (struct sockaddr *)&sa, sizeof(sa));
+		timeout_check("connect");
+	} while (ret < 0 && errno == EINTR);
+	timeout_end();
+
+	return ret;
+}
+
+/* Bind to <bind_port>, connect to <cid, port> and return the file descriptor. */
+int vsock_bind_connect(unsigned int cid, unsigned int port, unsigned int bind_port, int type)
+{
+	int client_fd;
+
+	client_fd = vsock_bind(VMADDR_CID_ANY, bind_port, type);
+
+	if (vsock_connect_fd(client_fd, cid, port)) {
+		perror("connect");
+		exit(EXIT_FAILURE);
+	}
+
+	return client_fd;
+}
+
+/* Connect to <cid, port> and return the file descriptor. */
+int vsock_connect(unsigned int cid, unsigned int port, int type)
+{
+	int fd;
+
+	control_expectln("LISTENING");
+
+	fd = socket(AF_VSOCK, type, 0);
+	if (fd < 0) {
+		perror("socket");
+		exit(EXIT_FAILURE);
+	}
+
+	if (vsock_connect_fd(fd, cid, port)) {
+		int old_errno = errno;
+
+		close(fd);
+		fd = -1;
+		errno = old_errno;
+	}
+
+	return fd;
+}
+
+int vsock_stream_connect(unsigned int cid, unsigned int port)
+{
+	return vsock_connect(cid, port, SOCK_STREAM);
+}
+
+int vsock_seqpacket_connect(unsigned int cid, unsigned int port)
+{
+	return vsock_connect(cid, port, SOCK_SEQPACKET);
+}
+
+/* Listen on <cid, port> and return the file descriptor. */
+static int vsock_listen(unsigned int cid, unsigned int port, int type)
+{
+	int fd;
+
+	fd = vsock_bind(cid, port, type);
+
+	if (listen(fd, 1) < 0) {
+		perror("listen");
+		exit(EXIT_FAILURE);
+	}
+
+	return fd;
+}
+
+/* Listen on <cid, port> and return the first incoming connection.  The remote
+ * address is stored to clientaddrp.  clientaddrp may be NULL.
+ */
+int vsock_accept(unsigned int cid, unsigned int port,
+		 struct sockaddr_vm *clientaddrp, int type)
+{
+	union {
+		struct sockaddr sa;
+		struct sockaddr_vm svm;
+	} clientaddr;
+	socklen_t clientaddr_len = sizeof(clientaddr.svm);
+	int fd, client_fd, old_errno;
+
+	fd = vsock_listen(cid, port, type);
+
+	control_writeln("LISTENING");
+
+	timeout_begin(TIMEOUT);
+	do {
+		client_fd = accept(fd, &clientaddr.sa, &clientaddr_len);
+		timeout_check("accept");
+	} while (client_fd < 0 && errno == EINTR);
+	timeout_end();
+
+	old_errno = errno;
+	close(fd);
+	errno = old_errno;
+
+	if (client_fd < 0)
+		return client_fd;
+
+	if (clientaddr_len != sizeof(clientaddr.svm)) {
+		fprintf(stderr, "unexpected addrlen from accept(2), %zu\n",
+			(size_t)clientaddr_len);
+		exit(EXIT_FAILURE);
+	}
+	if (clientaddr.sa.sa_family != AF_VSOCK) {
+		fprintf(stderr, "expected AF_VSOCK from accept(2), got %d\n",
+			clientaddr.sa.sa_family);
+		exit(EXIT_FAILURE);
+	}
+
+	if (clientaddrp)
+		*clientaddrp = clientaddr.svm;
+	return client_fd;
+}
+
+int vsock_stream_accept(unsigned int cid, unsigned int port,
+			struct sockaddr_vm *clientaddrp)
+{
+	return vsock_accept(cid, port, clientaddrp, SOCK_STREAM);
+}
+
+int vsock_stream_listen(unsigned int cid, unsigned int port)
+{
+	return vsock_listen(cid, port, SOCK_STREAM);
+}
+
+int vsock_seqpacket_accept(unsigned int cid, unsigned int port,
+			   struct sockaddr_vm *clientaddrp)
+{
+	return vsock_accept(cid, port, clientaddrp, SOCK_SEQPACKET);
+}
+
+/* Transmit bytes from a buffer and check the return value.
+ *
+ * expected_ret:
+ *  <0 Negative errno (for testing errors)
+ *   0 End-of-file
+ *  >0 Success (bytes successfully written)
+ */
+void send_buf(int fd, const void *buf, size_t len, int flags,
+	      ssize_t expected_ret)
+{
+	ssize_t nwritten = 0;
+	ssize_t ret;
+
+	timeout_begin(TIMEOUT);
+	do {
+		ret = send(fd, buf + nwritten, len - nwritten, flags);
+		timeout_check("send");
+
+		if (ret < 0 && errno == EINTR)
+			continue;
+		if (ret <= 0)
+			break;
+
+		nwritten += ret;
+	} while (nwritten < len);
+	timeout_end();
+
+	if (expected_ret < 0) {
+		if (ret != -1) {
+			fprintf(stderr, "bogus send(2) return value %zd (expected %zd)\n",
+				ret, expected_ret);
+			exit(EXIT_FAILURE);
+		}
+		if (errno != -expected_ret) {
+			perror("send");
+			exit(EXIT_FAILURE);
+		}
+		return;
+	}
+
+	if (ret < 0) {
+		perror("send");
+		exit(EXIT_FAILURE);
+	}
+
+	if (nwritten != expected_ret) {
+		if (ret == 0)
+			fprintf(stderr, "unexpected EOF while sending bytes\n");
+
+		fprintf(stderr, "bogus send(2) bytes written %zd (expected %zd)\n",
+			nwritten, expected_ret);
+		exit(EXIT_FAILURE);
+	}
+}
+
+#define RECV_PEEK_RETRY_USEC (10 * 1000)
+
+/* Receive bytes in a buffer and check the return value.
+ *
+ * When MSG_PEEK is set, recv() is retried until it returns at least
+ * expected_ret bytes. The function returns on error, EOF, or timeout
+ * as usual.
+ *
+ * expected_ret:
+ *  <0 Negative errno (for testing errors)
+ *   0 End-of-file
+ *  >0 Success (bytes successfully read)
+ */
+void recv_buf(int fd, void *buf, size_t len, int flags, ssize_t expected_ret)
+{
+	ssize_t nread = 0;
+	ssize_t ret;
+
+	timeout_begin(TIMEOUT);
+	do {
+		ret = recv(fd, buf + nread, len - nread, flags);
+		timeout_check("recv");
+
+		if (ret < 0 && errno == EINTR)
+			continue;
+		if (ret <= 0)
+			break;
+
+		if (flags & MSG_PEEK) {
+			if (ret >= expected_ret) {
+				nread = ret;
+				break;
+			}
+			timeout_usleep(RECV_PEEK_RETRY_USEC);
+			continue;
+		}
+
+		nread += ret;
+	} while (nread < len);
+	timeout_end();
+
+	if (expected_ret < 0) {
+		if (ret != -1) {
+			fprintf(stderr, "bogus recv(2) return value %zd (expected %zd)\n",
+				ret, expected_ret);
+			exit(EXIT_FAILURE);
+		}
+		if (errno != -expected_ret) {
+			perror("recv");
+			exit(EXIT_FAILURE);
+		}
+		return;
+	}
+
+	if (ret < 0) {
+		perror("recv");
+		exit(EXIT_FAILURE);
+	}
+
+	if (nread != expected_ret) {
+		if (ret == 0)
+			fprintf(stderr, "unexpected EOF while receiving bytes\n");
+
+		fprintf(stderr, "bogus recv(2) bytes read %zd (expected %zd)\n",
+			nread, expected_ret);
+		exit(EXIT_FAILURE);
+	}
+}
+
+/* Transmit one byte and check the return value.
+ *
+ * expected_ret:
+ *  <0 Negative errno (for testing errors)
+ *   0 End-of-file
+ *   1 Success
+ */
+void send_byte(int fd, int expected_ret, int flags)
+{
+	static const uint8_t byte = 'A';
+
+	send_buf(fd, &byte, sizeof(byte), flags, expected_ret);
+}
+
+/* Receive one byte and check the return value.
+ *
+ * expected_ret:
+ *  <0 Negative errno (for testing errors)
+ *   0 End-of-file
+ *   1 Success
+ */
+void recv_byte(int fd, int expected_ret, int flags)
+{
+	uint8_t byte;
+
+	recv_buf(fd, &byte, sizeof(byte), flags, expected_ret);
+
+	if (byte != 'A') {
+		fprintf(stderr, "unexpected byte read 0x%02x\n", byte);
+		exit(EXIT_FAILURE);
+	}
+}
+
+/* Run test cases.  The program terminates if a failure occurs. */
+void run_tests(const struct test_case *test_cases,
+	       const struct test_opts *opts)
+{
+	int i;
+
+	for (i = 0; test_cases[i].name; i++) {
+		void (*run)(const struct test_opts *opts);
+		char *line;
+
+		printf("%d - %s...", i, test_cases[i].name);
+		fflush(stdout);
+
+		/* Full barrier before executing the next test.  This
+		 * ensures that client and server are executing the
+		 * same test case.  In particular, it means whoever is
+		 * faster will not see the peer still executing the
+		 * last test.  This is important because port numbers
+		 * can be used by multiple test cases.
+		 */
+		if (test_cases[i].skip)
+			control_writeln("SKIP");
+		else
+			control_writeln("NEXT");
+
+		line = control_readln();
+		if (control_cmpln(line, "SKIP", false) || test_cases[i].skip) {
+
+			printf("skipped\n");
+
+			free(line);
+			continue;
+		}
+
+		control_cmpln(line, "NEXT", true);
+		free(line);
+
+		if (opts->mode == TEST_MODE_CLIENT)
+			run = test_cases[i].run_client;
+		else
+			run = test_cases[i].run_server;
+
+		if (run)
+			run(opts);
+
+		printf("ok\n");
+	}
+
+	printf("All tests have been executed. Waiting other peer...");
+	fflush(stdout);
+
+	/*
+	 * Final full barrier, to ensure that all tests have been run and
+	 * that even the last one has been successful on both sides.
+	 */
+	control_writeln("COMPLETED");
+	control_expectln("COMPLETED");
+
+	printf("ok\n");
+}
+
+void list_tests(const struct test_case *test_cases)
+{
+	int i;
+
+	printf("ID\tTest name\n");
+
+	for (i = 0; test_cases[i].name; i++)
+		printf("%d\t%s\n", i, test_cases[i].name);
+
+	exit(EXIT_FAILURE);
+}
+
+static unsigned long parse_test_id(const char *test_id_str, size_t test_cases_len)
+{
+	unsigned long test_id;
+	char *endptr = NULL;
+
+	errno = 0;
+	test_id = strtoul(test_id_str, &endptr, 10);
+	if (errno || *endptr != '\0') {
+		fprintf(stderr, "malformed test ID \"%s\"\n", test_id_str);
+		exit(EXIT_FAILURE);
+	}
+
+	if (test_id >= test_cases_len) {
+		fprintf(stderr, "test ID (%lu) larger than the max allowed (%lu)\n",
+			test_id, test_cases_len - 1);
+		exit(EXIT_FAILURE);
+	}
+
+	return test_id;
+}
+
+void skip_test(struct test_case *test_cases, size_t test_cases_len,
+	       const char *test_id_str)
+{
+	unsigned long test_id = parse_test_id(test_id_str, test_cases_len);
+	test_cases[test_id].skip = true;
+}
+
+void pick_test(struct test_case *test_cases, size_t test_cases_len,
+	       const char *test_id_str)
+{
+	static bool skip_all = true;
+	unsigned long test_id;
+
+	if (skip_all) {
+		unsigned long i;
+
+		for (i = 0; i < test_cases_len; ++i)
+			test_cases[i].skip = true;
+
+		skip_all = false;
+	}
+
+	test_id = parse_test_id(test_id_str, test_cases_len);
+	test_cases[test_id].skip = false;
+}
+
+unsigned long hash_djb2(const void *data, size_t len)
+{
+	unsigned long hash = 5381;
+	int i = 0;
+
+	while (i < len) {
+		hash = ((hash << 5) + hash) + ((unsigned char *)data)[i];
+		i++;
+	}
+
+	return hash;
+}
+
+size_t iovec_bytes(const struct iovec *iov, size_t iovnum)
+{
+	size_t bytes;
+	int i;
+
+	for (bytes = 0, i = 0; i < iovnum; i++)
+		bytes += iov[i].iov_len;
+
+	return bytes;
+}
+
+unsigned long iovec_hash_djb2(const struct iovec *iov, size_t iovnum)
+{
+	unsigned long hash;
+	size_t iov_bytes;
+	size_t offs;
+	void *tmp;
+	int i;
+
+	iov_bytes = iovec_bytes(iov, iovnum);
+
+	tmp = malloc(iov_bytes);
+	if (!tmp) {
+		perror("malloc");
+		exit(EXIT_FAILURE);
+	}
+
+	for (offs = 0, i = 0; i < iovnum; i++) {
+		memcpy(tmp + offs, iov[i].iov_base, iov[i].iov_len);
+		offs += iov[i].iov_len;
+	}
+
+	hash = hash_djb2(tmp, iov_bytes);
+	free(tmp);
+
+	return hash;
+}
+
+/* Allocates and returns new 'struct iovec *' according pattern
+ * in the 'test_iovec'. For each element in the 'test_iovec' it
+ * allocates new element in the resulting 'iovec'. 'iov_len'
+ * of the new element is copied from 'test_iovec'. 'iov_base' is
+ * allocated depending on the 'iov_base' of 'test_iovec':
+ *
+ * 'iov_base' == NULL -> valid buf: mmap('iov_len').
+ *
+ * 'iov_base' == MAP_FAILED -> invalid buf:
+ *               mmap('iov_len'), then munmap('iov_len').
+ *               'iov_base' still contains result of
+ *               mmap().
+ *
+ * 'iov_base' == number -> unaligned valid buf:
+ *               mmap('iov_len') + number.
+ *
+ * 'iovnum' is number of elements in 'test_iovec'.
+ *
+ * Returns new 'iovec' or calls 'exit()' on error.
+ */
+struct iovec *alloc_test_iovec(const struct iovec *test_iovec, int iovnum)
+{
+	struct iovec *iovec;
+	int i;
+
+	iovec = malloc(sizeof(*iovec) * iovnum);
+	if (!iovec) {
+		perror("malloc");
+		exit(EXIT_FAILURE);
+	}
+
+	for (i = 0; i < iovnum; i++) {
+		iovec[i].iov_len = test_iovec[i].iov_len;
+
+		iovec[i].iov_base = mmap(NULL, iovec[i].iov_len,
+					 PROT_READ | PROT_WRITE,
+					 MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE,
+					 -1, 0);
+		if (iovec[i].iov_base == MAP_FAILED) {
+			perror("mmap");
+			exit(EXIT_FAILURE);
+		}
+
+		if (test_iovec[i].iov_base != MAP_FAILED)
+			iovec[i].iov_base += (uintptr_t)test_iovec[i].iov_base;
+	}
+
+	/* Unmap "invalid" elements. */
+	for (i = 0; i < iovnum; i++) {
+		if (test_iovec[i].iov_base == MAP_FAILED) {
+			if (munmap(iovec[i].iov_base, iovec[i].iov_len)) {
+				perror("munmap");
+				exit(EXIT_FAILURE);
+			}
+		}
+	}
+
+	for (i = 0; i < iovnum; i++) {
+		int j;
+
+		if (test_iovec[i].iov_base == MAP_FAILED)
+			continue;
+
+		for (j = 0; j < iovec[i].iov_len; j++)
+			((uint8_t *)iovec[i].iov_base)[j] = rand() & 0xff;
+	}
+
+	return iovec;
+}
+
+/* Frees 'iovec *', previously allocated by 'alloc_test_iovec()'.
+ * On error calls 'exit()'.
+ */
+void free_test_iovec(const struct iovec *test_iovec,
+		     struct iovec *iovec, int iovnum)
+{
+	int i;
+
+	for (i = 0; i < iovnum; i++) {
+		if (test_iovec[i].iov_base != MAP_FAILED) {
+			if (test_iovec[i].iov_base)
+				iovec[i].iov_base -= (uintptr_t)test_iovec[i].iov_base;
+
+			if (munmap(iovec[i].iov_base, iovec[i].iov_len)) {
+				perror("munmap");
+				exit(EXIT_FAILURE);
+			}
+		}
+	}
+
+	free(iovec);
+}
+
+/* Set "unsigned long long" socket option and check that it's indeed set */
+void setsockopt_ull_check(int fd, int level, int optname,
+			  unsigned long long val, char const *errmsg)
+{
+	unsigned long long chkval;
+	socklen_t chklen;
+	int err;
+
+	err = setsockopt(fd, level, optname, &val, sizeof(val));
+	if (err) {
+		fprintf(stderr, "setsockopt err: %s (%d)\n",
+			strerror(errno), errno);
+		goto fail;
+	}
+
+	chkval = ~val; /* just make storage != val */
+	chklen = sizeof(chkval);
+
+	err = getsockopt(fd, level, optname, &chkval, &chklen);
+	if (err) {
+		fprintf(stderr, "getsockopt err: %s (%d)\n",
+			strerror(errno), errno);
+		goto fail;
+	}
+
+	if (chklen != sizeof(chkval)) {
+		fprintf(stderr, "size mismatch: set %zu got %d\n", sizeof(val),
+			chklen);
+		goto fail;
+	}
+
+	if (chkval != val) {
+		fprintf(stderr, "value mismatch: set %llu got %llu\n", val,
+			chkval);
+		goto fail;
+	}
+	return;
+fail:
+	fprintf(stderr, "%s  val %llu\n", errmsg, val);
+	exit(EXIT_FAILURE);
+}
+
+/* Set "int" socket option and check that it's indeed set */
+void setsockopt_int_check(int fd, int level, int optname, int val,
+			  char const *errmsg)
+{
+	int chkval;
+	socklen_t chklen;
+	int err;
+
+	err = setsockopt(fd, level, optname, &val, sizeof(val));
+	if (err) {
+		fprintf(stderr, "setsockopt err: %s (%d)\n",
+			strerror(errno), errno);
+		goto fail;
+	}
+
+	chkval = ~val; /* just make storage != val */
+	chklen = sizeof(chkval);
+
+	err = getsockopt(fd, level, optname, &chkval, &chklen);
+	if (err) {
+		fprintf(stderr, "getsockopt err: %s (%d)\n",
+			strerror(errno), errno);
+		goto fail;
+	}
+
+	if (chklen != sizeof(chkval)) {
+		fprintf(stderr, "size mismatch: set %zu got %d\n", sizeof(val),
+			chklen);
+		goto fail;
+	}
+
+	if (chkval != val) {
+		fprintf(stderr, "value mismatch: set %d got %d\n", val, chkval);
+		goto fail;
+	}
+	return;
+fail:
+	fprintf(stderr, "%s val %d\n", errmsg, val);
+	exit(EXIT_FAILURE);
+}
+
+static void mem_invert(unsigned char *mem, size_t size)
+{
+	size_t i;
+
+	for (i = 0; i < size; i++)
+		mem[i] = ~mem[i];
+}
+
+/* Set "timeval" socket option and check that it's indeed set */
+void setsockopt_timeval_check(int fd, int level, int optname,
+			      struct timeval val, char const *errmsg)
+{
+	struct timeval chkval;
+	socklen_t chklen;
+	int err;
+
+	err = setsockopt(fd, level, optname, &val, sizeof(val));
+	if (err) {
+		fprintf(stderr, "setsockopt err: %s (%d)\n",
+			strerror(errno), errno);
+		goto fail;
+	}
+
+	 /* just make storage != val */
+	chkval = val;
+	mem_invert((unsigned char *)&chkval, sizeof(chkval));
+	chklen = sizeof(chkval);
+
+	err = getsockopt(fd, level, optname, &chkval, &chklen);
+	if (err) {
+		fprintf(stderr, "getsockopt err: %s (%d)\n",
+			strerror(errno), errno);
+		goto fail;
+	}
+
+	if (chklen != sizeof(chkval)) {
+		fprintf(stderr, "size mismatch: set %zu got %d\n", sizeof(val),
+			chklen);
+		goto fail;
+	}
+
+	if (memcmp(&chkval, &val, sizeof(val)) != 0) {
+		fprintf(stderr, "value mismatch: set %ld:%ld got %ld:%ld\n",
+			val.tv_sec, val.tv_usec, chkval.tv_sec, chkval.tv_usec);
+		goto fail;
+	}
+	return;
+fail:
+	fprintf(stderr, "%s val %ld:%ld\n", errmsg, val.tv_sec, val.tv_usec);
+	exit(EXIT_FAILURE);
+}
+
+void enable_so_zerocopy_check(int fd)
+{
+	setsockopt_int_check(fd, SOL_SOCKET, SO_ZEROCOPY, 1,
+			     "setsockopt SO_ZEROCOPY");
+}
+
+void enable_so_linger(int fd, int timeout)
+{
+	struct linger optval = {
+		.l_onoff = 1,
+		.l_linger = timeout
+	};
+
+	if (setsockopt(fd, SOL_SOCKET, SO_LINGER, &optval, sizeof(optval))) {
+		perror("setsockopt(SO_LINGER)");
+		exit(EXIT_FAILURE);
+	}
+}
+
+static int __get_transports(void)
+{
+	char buf[KALLSYMS_LINE_LEN];
+	const char *ksym;
+	int ret = 0;
+	FILE *f;
+
+	f = fopen(KALLSYMS_PATH, "r");
+	if (!f) {
+		perror("Can't open " KALLSYMS_PATH);
+		exit(EXIT_FAILURE);
+	}
+
+	while (fgets(buf, sizeof(buf), f)) {
+		char *match;
+		int i;
+
+		assert(buf[strlen(buf) - 1] == '\n');
+
+		for (i = 0; i < TRANSPORT_NUM; ++i) {
+			if (ret & BIT(i))
+				continue;
+
+			/* Match should be followed by '\t' or '\n'.
+			 * See kallsyms.c:s_show().
+			 */
+			ksym = transport_ksyms[i];
+			match = strstr(buf, ksym);
+			if (match && isspace(match[strlen(ksym)])) {
+				ret |= BIT(i);
+				break;
+			}
+		}
+	}
+
+	fclose(f);
+	return ret;
+}
+
+/* Return integer with TRANSPORT_* bit set for every (known) registered vsock
+ * transport.
+ */
+int get_transports(void)
+{
+	static int tr = -1;
+
+	if (tr == -1)
+		tr = __get_transports();
+
+	return tr;
+}