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
  ...

5 files changed, 1744 insertions, 0 deletions

diff --git a/tools/testing/selftests/vsock/.gitignore b/tools/testing/selftests/vsock/.gitignore
new file mode 100644
index 000000000..9c5bf3794
--- /dev/null
+++ b/tools/testing/selftests/vsock/.gitignore
@@ -0,0 +1,2 @@
+vmtest.log
+vsock_test
diff --git a/tools/testing/selftests/vsock/Makefile b/tools/testing/selftests/vsock/Makefile
new file mode 100644
index 000000000..c407c0afd
--- /dev/null
+++ b/tools/testing/selftests/vsock/Makefile
@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: GPL-2.0
+
+CURDIR := $(abspath .)
+TOOLSDIR := $(abspath ../../..)
+VSOCK_TEST_DIR := $(TOOLSDIR)/testing/vsock
+VSOCK_TEST_SRCS := $(wildcard $(VSOCK_TEST_DIR)/*.c $(VSOCK_TEST_DIR)/*.h)
+
+$(OUTPUT)/vsock_test: $(VSOCK_TEST_DIR)/vsock_test
+	install -m 755 $< $@
+
+$(VSOCK_TEST_DIR)/vsock_test: $(VSOCK_TEST_SRCS)
+	$(MAKE) -C $(VSOCK_TEST_DIR) vsock_test
+TEST_PROGS += vmtest.sh
+TEST_GEN_FILES := vsock_test
+
+include ../lib.mk
+
diff --git a/tools/testing/selftests/vsock/config b/tools/testing/selftests/vsock/config
new file mode 100644
index 000000000..5f0a4f17d
--- /dev/null
+++ b/tools/testing/selftests/vsock/config
@@ -0,0 +1,111 @@
+CONFIG_BLK_DEV_INITRD=y
+CONFIG_BPF=y
+CONFIG_BPF_SYSCALL=y
+CONFIG_BPF_JIT=y
+CONFIG_HAVE_EBPF_JIT=y
+CONFIG_BPF_EVENTS=y
+CONFIG_FTRACE_SYSCALLS=y
+CONFIG_FUNCTION_TRACER=y
+CONFIG_HAVE_DYNAMIC_FTRACE=y
+CONFIG_DYNAMIC_FTRACE=y
+CONFIG_HAVE_KPROBES=y
+CONFIG_KPROBES=y
+CONFIG_KPROBE_EVENTS=y
+CONFIG_ARCH_SUPPORTS_UPROBES=y
+CONFIG_UPROBES=y
+CONFIG_UPROBE_EVENTS=y
+CONFIG_DEBUG_FS=y
+CONFIG_FW_CFG_SYSFS=y
+CONFIG_FW_CFG_SYSFS_CMDLINE=y
+CONFIG_DRM=y
+CONFIG_DRM_VIRTIO_GPU=y
+CONFIG_DRM_VIRTIO_GPU_KMS=y
+CONFIG_DRM_BOCHS=y
+CONFIG_VIRTIO_IOMMU=y
+CONFIG_SOUND=y
+CONFIG_SND=y
+CONFIG_SND_SEQUENCER=y
+CONFIG_SND_PCI=y
+CONFIG_SND_INTEL8X0=y
+CONFIG_SND_HDA_CODEC_REALTEK=y
+CONFIG_SECURITYFS=y
+CONFIG_CGROUP_BPF=y
+CONFIG_SQUASHFS=y
+CONFIG_SQUASHFS_XZ=y
+CONFIG_SQUASHFS_ZSTD=y
+CONFIG_FUSE_FS=y
+CONFIG_VIRTIO_FS=y
+CONFIG_SERIO=y
+CONFIG_PCI=y
+CONFIG_INPUT=y
+CONFIG_INPUT_KEYBOARD=y
+CONFIG_KEYBOARD_ATKBD=y
+CONFIG_SERIAL_8250=y
+CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_X86_VERBOSE_BOOTUP=y
+CONFIG_VGA_CONSOLE=y
+CONFIG_FB=y
+CONFIG_FB_VESA=y
+CONFIG_FRAMEBUFFER_CONSOLE=y
+CONFIG_RTC_CLASS=y
+CONFIG_RTC_HCTOSYS=y
+CONFIG_RTC_DRV_CMOS=y
+CONFIG_HYPERVISOR_GUEST=y
+CONFIG_PARAVIRT=y
+CONFIG_KVM_GUEST=y
+CONFIG_KVM=y
+CONFIG_KVM_INTEL=y
+CONFIG_KVM_AMD=y
+CONFIG_VSOCKETS=y
+CONFIG_VSOCKETS_DIAG=y
+CONFIG_VSOCKETS_LOOPBACK=y
+CONFIG_VMWARE_VMCI_VSOCKETS=y
+CONFIG_VIRTIO_VSOCKETS=y
+CONFIG_VIRTIO_VSOCKETS_COMMON=y
+CONFIG_HYPERV_VSOCKETS=y
+CONFIG_VMWARE_VMCI=y
+CONFIG_VHOST_VSOCK=y
+CONFIG_HYPERV=y
+CONFIG_UEVENT_HELPER=n
+CONFIG_VIRTIO=y
+CONFIG_VIRTIO_PCI=y
+CONFIG_VIRTIO_MMIO=y
+CONFIG_VIRTIO_BALLOON=y
+CONFIG_NET=y
+CONFIG_NET_CORE=y
+CONFIG_NETDEVICES=y
+CONFIG_NETWORK_FILESYSTEMS=y
+CONFIG_INET=y
+CONFIG_NET_9P=y
+CONFIG_NET_9P_VIRTIO=y
+CONFIG_9P_FS=y
+CONFIG_VIRTIO_NET=y
+CONFIG_CMDLINE_OVERRIDE=n
+CONFIG_BINFMT_SCRIPT=y
+CONFIG_SHMEM=y
+CONFIG_TMPFS=y
+CONFIG_UNIX=y
+CONFIG_MODULE_SIG_FORCE=n
+CONFIG_DEVTMPFS=y
+CONFIG_TTY=y
+CONFIG_VT=y
+CONFIG_UNIX98_PTYS=y
+CONFIG_EARLY_PRINTK=y
+CONFIG_INOTIFY_USER=y
+CONFIG_BLOCK=y
+CONFIG_SCSI_LOWLEVEL=y
+CONFIG_SCSI=y
+CONFIG_SCSI_VIRTIO=y
+CONFIG_BLK_DEV_SD=y
+CONFIG_VIRTIO_CONSOLE=y
+CONFIG_WATCHDOG=y
+CONFIG_WATCHDOG_CORE=y
+CONFIG_I6300ESB_WDT=y
+CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y
+CONFIG_OVERLAY_FS=y
+CONFIG_DAX=y
+CONFIG_DAX_DRIVER=y
+CONFIG_FS_DAX=y
+CONFIG_MEMORY_HOTPLUG=y
+CONFIG_MEMORY_HOTREMOVE=y
+CONFIG_ZONE_DEVICE=y
diff --git a/tools/testing/selftests/vsock/settings b/tools/testing/selftests/vsock/settings
new file mode 100644
index 000000000..79b65bdf0
--- /dev/null
+++ b/tools/testing/selftests/vsock/settings
@@ -0,0 +1 @@
+timeout=1200
diff --git a/tools/testing/selftests/vsock/vmtest.sh b/tools/testing/selftests/vsock/vmtest.sh
new file mode 100755
index 000000000..310dfc2a3
--- /dev/null
+++ b/tools/testing/selftests/vsock/vmtest.sh
@@ -0,0 +1,1613 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (c) 2025 Meta Platforms, Inc. and affiliates
+#
+# Dependencies:
+#		* virtme-ng
+#		* busybox-static (used by virtme-ng)
+#		* qemu	(used by virtme-ng)
+#		* socat
+#
+# shellcheck disable=SC2317,SC2119
+
+readonly SCRIPT_DIR="$(cd -P -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd -P)"
+readonly KERNEL_CHECKOUT=$(realpath "${SCRIPT_DIR}"/../../../../)
+
+source "${SCRIPT_DIR}"/../kselftest/ktap_helpers.sh
+
+readonly VSOCK_TEST="${SCRIPT_DIR}"/vsock_test
+readonly TEST_GUEST_PORT=51000
+readonly TEST_HOST_PORT=50000
+readonly TEST_HOST_PORT_LISTENER=50001
+readonly SSH_GUEST_PORT=22
+readonly SSH_HOST_PORT=2222
+readonly VSOCK_CID=1234
+readonly WAIT_PERIOD=3
+readonly WAIT_PERIOD_MAX=60
+readonly WAIT_QEMU=5
+readonly PIDFILE_TEMPLATE=/tmp/vsock_vmtest_XXXX.pid
+declare -A PIDFILES
+
+# virtme-ng offers a netdev for ssh when using "--ssh", but we also need a
+# control port forwarded for vsock_test.  Because virtme-ng doesn't support
+# adding an additional port to forward to the device created from "--ssh" and
+# virtme-init mistakenly sets identical IPs to the ssh device and additional
+# devices, we instead opt out of using --ssh, add the device manually, and also
+# add the kernel cmdline options that virtme-init uses to setup the interface.
+readonly QEMU_TEST_PORT_FWD="hostfwd=tcp::${TEST_HOST_PORT}-:${TEST_GUEST_PORT}"
+readonly QEMU_SSH_PORT_FWD="hostfwd=tcp::${SSH_HOST_PORT}-:${SSH_GUEST_PORT}"
+readonly KERNEL_CMDLINE="\
+	virtme.dhcp net.ifnames=0 biosdevname=0 \
+	virtme.ssh virtme_ssh_channel=tcp virtme_ssh_user=$USER \
+"
+readonly LOG=$(mktemp /tmp/vsock_vmtest_XXXX.log)
+readonly TEST_HOME="$(mktemp -d /tmp/vmtest_home_XXXX)"
+readonly SSH_KEY_PATH="${TEST_HOME}"/.ssh/id_ed25519
+
+# Namespace tests must use the ns_ prefix. This is checked in check_netns() and
+# is used to determine if a test needs namespace setup before test execution.
+readonly TEST_NAMES=(
+	vm_server_host_client
+	vm_client_host_server
+	vm_loopback
+	ns_host_vsock_ns_mode_ok
+	ns_host_vsock_child_ns_mode_ok
+	ns_global_same_cid_fails
+	ns_local_same_cid_ok
+	ns_global_local_same_cid_ok
+	ns_local_global_same_cid_ok
+	ns_diff_global_host_connect_to_global_vm_ok
+	ns_diff_global_host_connect_to_local_vm_fails
+	ns_diff_global_vm_connect_to_global_host_ok
+	ns_diff_global_vm_connect_to_local_host_fails
+	ns_diff_local_host_connect_to_local_vm_fails
+	ns_diff_local_vm_connect_to_local_host_fails
+	ns_diff_global_to_local_loopback_local_fails
+	ns_diff_local_to_global_loopback_fails
+	ns_diff_local_to_local_loopback_fails
+	ns_diff_global_to_global_loopback_ok
+	ns_same_local_loopback_ok
+	ns_same_local_host_connect_to_local_vm_ok
+	ns_same_local_vm_connect_to_local_host_ok
+	ns_delete_vm_ok
+	ns_delete_host_ok
+	ns_delete_both_ok
+)
+readonly TEST_DESCS=(
+	# vm_server_host_client
+	"Run vsock_test in server mode on the VM and in client mode on the host."
+
+	# vm_client_host_server
+	"Run vsock_test in client mode on the VM and in server mode on the host."
+
+	# vm_loopback
+	"Run vsock_test using the loopback transport in the VM."
+
+	# ns_host_vsock_ns_mode_ok
+	"Check /proc/sys/net/vsock/ns_mode strings on the host."
+
+	# ns_host_vsock_child_ns_mode_ok
+	"Check /proc/sys/net/vsock/ns_mode is read-only and child_ns_mode is writable."
+
+	# ns_global_same_cid_fails
+	"Check QEMU fails to start two VMs with same CID in two different global namespaces."
+
+	# ns_local_same_cid_ok
+	"Check QEMU successfully starts two VMs with same CID in two different local namespaces."
+
+	# ns_global_local_same_cid_ok
+	"Check QEMU successfully starts one VM in a global ns and then another VM in a local ns with the same CID."
+
+	# ns_local_global_same_cid_ok
+	"Check QEMU successfully starts one VM in a local ns and then another VM in a global ns with the same CID."
+
+	# ns_diff_global_host_connect_to_global_vm_ok
+	"Run vsock_test client in global ns with server in VM in another global ns."
+
+	# ns_diff_global_host_connect_to_local_vm_fails
+	"Run socat to test a process in a global ns fails to connect to a VM in a local ns."
+
+	# ns_diff_global_vm_connect_to_global_host_ok
+	"Run vsock_test client in VM in a global ns with server in another global ns."
+
+	# ns_diff_global_vm_connect_to_local_host_fails
+	"Run socat to test a VM in a global ns fails to connect to a host process in a local ns."
+
+	# ns_diff_local_host_connect_to_local_vm_fails
+	"Run socat to test a host process in a local ns fails to connect to a VM in another local ns."
+
+	# ns_diff_local_vm_connect_to_local_host_fails
+	"Run socat to test a VM in a local ns fails to connect to a host process in another local ns."
+
+	# ns_diff_global_to_local_loopback_local_fails
+	"Run socat to test a loopback vsock in a global ns fails to connect to a vsock in a local ns."
+
+	# ns_diff_local_to_global_loopback_fails
+	"Run socat to test a loopback vsock in a local ns fails to connect to a vsock in a global ns."
+
+	# ns_diff_local_to_local_loopback_fails
+	"Run socat to test a loopback vsock in a local ns fails to connect to a vsock in another local ns."
+
+	# ns_diff_global_to_global_loopback_ok
+	"Run socat to test a loopback vsock in a global ns successfully connects to a vsock in another global ns."
+
+	# ns_same_local_loopback_ok
+	"Run socat to test a loopback vsock in a local ns successfully connects to a vsock in the same ns."
+
+	# ns_same_local_host_connect_to_local_vm_ok
+	"Run vsock_test client in a local ns with server in VM in same ns."
+
+	# ns_same_local_vm_connect_to_local_host_ok
+	"Run vsock_test client in VM in a local ns with server in same ns."
+
+	# ns_delete_vm_ok
+	"Check that deleting the VM's namespace does not break the socket connection"
+
+	# ns_delete_host_ok
+	"Check that deleting the host's namespace does not break the socket connection"
+
+	# ns_delete_both_ok
+	"Check that deleting the VM and host's namespaces does not break the socket connection"
+)
+
+readonly USE_SHARED_VM=(
+	vm_server_host_client
+	vm_client_host_server
+	vm_loopback
+)
+readonly NS_MODES=("local" "global")
+
+VERBOSE=0
+
+usage() {
+	local name
+	local desc
+	local i
+
+	echo
+	echo "$0 [OPTIONS] [TEST]..."
+	echo "If no TEST argument is given, all tests will be run."
+	echo
+	echo "Options"
+	echo "  -b: build the kernel from the current source tree and use it for guest VMs"
+	echo "  -q: set the path to or name of qemu binary"
+	echo "  -v: verbose output"
+	echo
+	echo "Available tests"
+
+	for ((i = 0; i < ${#TEST_NAMES[@]}; i++)); do
+		name=${TEST_NAMES[${i}]}
+		desc=${TEST_DESCS[${i}]}
+		printf "\t%-55s%-35s\n" "${name}" "${desc}"
+	done
+	echo
+
+	exit 1
+}
+
+die() {
+	echo "$*" >&2
+	exit "${KSFT_FAIL}"
+}
+
+check_result() {
+	local rc arg
+
+	rc=$1
+	arg=$2
+
+	cnt_total=$(( cnt_total + 1 ))
+
+	if [[ ${rc} -eq ${KSFT_PASS} ]]; then
+		cnt_pass=$(( cnt_pass + 1 ))
+		echo "ok ${cnt_total} ${arg}"
+	elif [[ ${rc} -eq ${KSFT_SKIP} ]]; then
+		cnt_skip=$(( cnt_skip + 1 ))
+		echo "ok ${cnt_total} ${arg} # SKIP"
+	elif [[ ${rc} -eq ${KSFT_FAIL} ]]; then
+		cnt_fail=$(( cnt_fail + 1 ))
+		echo "not ok ${cnt_total} ${arg} # exit=${rc}"
+	fi
+}
+
+add_namespaces() {
+	ip netns add "global-parent" 2>/dev/null
+	echo "global" | ip netns exec "global-parent" \
+		tee /proc/sys/net/vsock/child_ns_mode &>/dev/null
+	ip netns add "local-parent" 2>/dev/null
+	echo "local" | ip netns exec "local-parent" \
+		tee /proc/sys/net/vsock/child_ns_mode &>/dev/null
+
+	nsenter --net=/var/run/netns/global-parent \
+		ip netns add "global0" 2>/dev/null
+	nsenter --net=/var/run/netns/global-parent \
+		ip netns add "global1" 2>/dev/null
+	nsenter --net=/var/run/netns/local-parent \
+		ip netns add "local0" 2>/dev/null
+	nsenter --net=/var/run/netns/local-parent \
+		ip netns add "local1" 2>/dev/null
+}
+
+init_namespaces() {
+	for mode in "${NS_MODES[@]}"; do
+		# we need lo for qemu port forwarding
+		ip netns exec "${mode}0" ip link set dev lo up
+		ip netns exec "${mode}1" ip link set dev lo up
+	done
+}
+
+del_namespaces() {
+	for mode in "${NS_MODES[@]}"; do
+		ip netns del "${mode}0" &>/dev/null
+		ip netns del "${mode}1" &>/dev/null
+		log_host "removed ns ${mode}0"
+		log_host "removed ns ${mode}1"
+	done
+	ip netns del "global-parent" &>/dev/null
+	ip netns del "local-parent" &>/dev/null
+}
+
+vm_ssh() {
+	local ns_exec
+
+	if [[ "${1}" == init_ns ]]; then
+		ns_exec=""
+	else
+		ns_exec="ip netns exec ${1}"
+	fi
+
+	shift
+
+	${ns_exec} ssh -q \
+		-i "${SSH_KEY_PATH}" \
+		-o UserKnownHostsFile=/dev/null \
+		-o StrictHostKeyChecking=no \
+		-p "${SSH_HOST_PORT}" \
+		localhost "$@"
+
+	return $?
+}
+
+cleanup() {
+	terminate_pidfiles "${!PIDFILES[@]}"
+	del_namespaces
+	rm -rf "${TEST_HOME}"
+}
+
+check_args() {
+	local found
+
+	for arg in "$@"; do
+		found=0
+		for name in "${TEST_NAMES[@]}"; do
+			if [[ "${name}" = "${arg}" ]]; then
+				found=1
+				break
+			fi
+		done
+
+		if [[ "${found}" -eq 0 ]]; then
+			echo "${arg} is not an available test" >&2
+			usage
+		fi
+	done
+
+	for arg in "$@"; do
+		if ! command -v > /dev/null "test_${arg}"; then
+			echo "Test ${arg} not found" >&2
+			usage
+		fi
+	done
+}
+
+check_deps() {
+	for dep in vng ${QEMU} busybox pkill ssh ss socat nsenter; do
+		if [[ ! -x $(command -v "${dep}") ]]; then
+			echo -e "skip:    dependency ${dep} not found!\n"
+			exit "${KSFT_SKIP}"
+		fi
+	done
+
+	if [[ ! -x $(command -v "${VSOCK_TEST}") ]]; then
+		printf "skip:    %s not found!" "${VSOCK_TEST}"
+		printf " Please build the kselftest vsock target.\n"
+		exit "${KSFT_SKIP}"
+	fi
+}
+
+check_netns() {
+	local tname=$1
+
+	# If the test requires NS support, check if NS support exists
+	# using /proc/self/ns
+	if [[ "${tname}" =~ ^ns_ ]] &&
+	   [[ ! -e /proc/self/ns ]]; then
+		log_host "No NS support detected for test ${tname}"
+		return 1
+	fi
+
+	return 0
+}
+
+# Compare MAJOR.MINOR versions numerically. Returns 0 (true) if $1 < $2.
+version_lt() {
+	local -a a=(${1//./ })
+	local -a b=(${2//./ })
+
+	if [[ "${a[0]}" -lt "${b[0]}" ]]; then
+		return 0
+	elif [[ "${a[0]}" -gt "${b[0]}" ]]; then
+		return 1
+	elif [[ "${a[1]}" -lt "${b[1]}" ]]; then
+		return 0
+	fi
+
+	return 1
+}
+
+check_vng() {
+	local version
+
+	version="$(vng --version | awk '{print $2}')"
+
+	# Supported: 1.33, or any version >= 1.36. 1.34 and 1.35 are untested.
+	if [[ "${version}" == "1.33" ]] || ! version_lt "${version}" "1.36"; then
+		return
+	fi
+
+	printf "warning: vng version '%s' has not been tested and may " "${version}" >&2
+	printf "not function properly.\n\tSupported: 1.33 or >= 1.36\n" >&2
+}
+
+check_socat() {
+	local support_string
+
+	support_string="$(socat -V)"
+
+	if [[ "${support_string}" != *"WITH_VSOCK 1"* ]]; then
+		die "err: socat is missing vsock support"
+	fi
+
+	if [[ "${support_string}" != *"WITH_UNIX 1"* ]]; then
+		die "err: socat is missing unix support"
+	fi
+}
+
+handle_build() {
+	if [[ ! "${BUILD}" -eq 1 ]]; then
+		return
+	fi
+
+	if [[ ! -d "${KERNEL_CHECKOUT}" ]]; then
+		echo "-b requires vmtest.sh called from the kernel source tree" >&2
+		exit 1
+	fi
+
+	pushd "${KERNEL_CHECKOUT}" &>/dev/null
+
+	if ! vng --kconfig --config "${SCRIPT_DIR}"/config; then
+		die "failed to generate .config for kernel source tree (${KERNEL_CHECKOUT})"
+	fi
+
+	if ! make -j$(nproc); then
+		die "failed to build kernel from source tree (${KERNEL_CHECKOUT})"
+	fi
+
+	popd &>/dev/null
+}
+
+setup_home() {
+	mkdir -p "$(dirname "${SSH_KEY_PATH}")"
+	ssh-keygen -t ed25519 -f "${SSH_KEY_PATH}" -N "" -q
+	cp "${VSOCK_TEST}" "${TEST_HOME}"/vsock_test
+}
+
+create_pidfile() {
+	local pidfile
+
+	pidfile=$(mktemp "${PIDFILE_TEMPLATE}")
+	PIDFILES["${pidfile}"]=1
+
+	echo "${pidfile}"
+}
+
+terminate_pidfiles() {
+	local pidfile
+
+	for pidfile in "$@"; do
+		if [[ -s "${pidfile}" ]]; then
+			pkill -SIGTERM -F "${pidfile}" > /dev/null 2>&1
+		fi
+
+		if [[ -e "${pidfile}" ]]; then
+			rm -f "${pidfile}"
+		fi
+
+		unset "PIDFILES[${pidfile}]"
+	done
+}
+
+terminate_pids() {
+	local pid
+
+	for pid in "$@"; do
+		kill -SIGTERM "${pid}" &>/dev/null || :
+	done
+}
+
+vng_dry_run() {
+	# WORKAROUND: use setsid to work around a virtme-ng bug where vng hangs
+	# when called from a background process group (e.g., under make
+	# kselftest). vng save/restores terminal settings using tcsetattr(),
+	# which is not allowed for background process groups because the
+	# controlling terminal is owned by the foreground process group. vng is
+	# stopped with SIGTTOU and hangs until kselftest's timer expires.
+	# setsid works around this by launching vng in a new session that has
+	# no controlling terminal, so tcsetattr() succeeds.
+	#
+	# Fixed in 1.41 (https://github.com/arighi/virtme-ng/pull/453).
+
+	if version_lt "$(vng --version | awk '{print $2}')" "1.41"; then
+		setsid -w vng --run "$@" --dry-run &>/dev/null
+	else
+		vng --run "$@" --dry-run &>/dev/null
+	fi
+}
+
+vm_start() {
+	local pidfile=$1
+	local ns=$2
+	local logfile=/dev/null
+	local verbose_opt=""
+	local kernel_opt=""
+	local qemu_opts=""
+	local ns_exec=""
+	local qemu
+
+	qemu=$(command -v "${QEMU}")
+
+	if [[ "${VERBOSE}" -eq 1 ]]; then
+		verbose_opt="--verbose"
+		logfile=/dev/stdout
+	fi
+
+	qemu_opts="\
+		 -netdev user,id=n0,${QEMU_TEST_PORT_FWD},${QEMU_SSH_PORT_FWD} \
+		 -device virtio-net-pci,netdev=n0 \
+		 -device vhost-vsock-pci,guest-cid=${VSOCK_CID} \
+		--pidfile ${pidfile}
+	"
+
+	if [[ "${BUILD}" -eq 1 ]]; then
+		kernel_opt="${KERNEL_CHECKOUT}"
+	elif vng_dry_run; then
+		kernel_opt=""
+	elif vng_dry_run "${KERNEL_CHECKOUT}"; then
+		kernel_opt="${KERNEL_CHECKOUT}"
+	else
+		die "No suitable kernel found"
+	fi
+
+	if [[ "${ns}" != "init_ns" ]]; then
+		ns_exec="ip netns exec ${ns}"
+	fi
+
+	${ns_exec} vng \
+		--run \
+		${kernel_opt} \
+		${verbose_opt} \
+		--rwdir=/root="${TEST_HOME}" \
+		--force-9p \
+		--cwd /root \
+		--qemu-opts="${qemu_opts}" \
+		--qemu="${qemu}" \
+		--user root \
+		--append "${KERNEL_CMDLINE}" \
+		&> ${logfile} &
+
+	timeout "${WAIT_QEMU}" \
+		bash -c 'while [[ ! -s '"${pidfile}"' ]]; do sleep 1; done; exit 0'
+}
+
+vm_wait_for_ssh() {
+	local ns=$1
+	local i
+
+	i=0
+	while true; do
+		if [[ ${i} -gt ${WAIT_PERIOD_MAX} ]]; then
+			die "Timed out waiting for guest ssh"
+		fi
+
+		if vm_ssh "${ns}" -- true; then
+			break
+		fi
+		i=$(( i + 1 ))
+		sleep ${WAIT_PERIOD}
+	done
+}
+
+# derived from selftests/net/net_helper.sh
+wait_for_listener()
+{
+	local port=$1
+	local interval=$2
+	local max_intervals=$3
+	local protocol=$4
+	local i
+
+	for i in $(seq "${max_intervals}"); do
+		case "${protocol}" in
+		tcp)
+			if ss --listening --tcp --numeric | grep -q ":${port} "; then
+				break
+			fi
+			;;
+		vsock)
+			if ss --listening --vsock --numeric | grep -q ":${port} "; then
+				break
+			fi
+			;;
+		unix)
+			# For unix sockets, port is actually the socket path
+			if ss --listening --unix | grep -q "${port}"; then
+				break
+			fi
+			;;
+		*)
+			echo "Unknown protocol: ${protocol}" >&2
+			break
+			;;
+		esac
+		sleep "${interval}"
+	done
+}
+
+vm_wait_for_listener() {
+	local ns=$1
+	local port=$2
+	local protocol=$3
+
+	vm_ssh "${ns}" <<EOF
+$(declare -f wait_for_listener)
+wait_for_listener ${port} ${WAIT_PERIOD} ${WAIT_PERIOD_MAX} ${protocol}
+EOF
+}
+
+host_wait_for_listener() {
+	local ns=$1
+	local port=$2
+	local protocol=$3
+
+	if [[ "${ns}" == "init_ns" ]]; then
+		wait_for_listener "${port}" "${WAIT_PERIOD}" "${WAIT_PERIOD_MAX}" "${protocol}"
+	else
+		ip netns exec "${ns}" bash <<-EOF
+			$(declare -f wait_for_listener)
+			wait_for_listener ${port} ${WAIT_PERIOD} ${WAIT_PERIOD_MAX} ${protocol}
+		EOF
+	fi
+}
+
+vm_dmesg_oops_count() {
+	local ns=$1
+
+	vm_ssh "${ns}" -- dmesg 2>/dev/null | grep -c -i 'Oops'
+}
+
+vm_dmesg_warn_count() {
+	local ns=$1
+
+	vm_ssh "${ns}" -- dmesg --level=warn 2>/dev/null | grep -c -i 'vsock'
+}
+
+vm_dmesg_check() {
+	local pidfile=$1
+	local ns=$2
+	local oops_before=$3
+	local warn_before=$4
+	local oops_after warn_after
+
+	oops_after=$(vm_dmesg_oops_count "${ns}")
+	if [[ "${oops_after}" -gt "${oops_before}" ]]; then
+		echo "FAIL: kernel oops detected on vm in ns ${ns}" | log_host
+		return 1
+	fi
+
+	warn_after=$(vm_dmesg_warn_count "${ns}")
+	if [[ "${warn_after}" -gt "${warn_before}" ]]; then
+		echo "FAIL: kernel warning detected on vm in ns ${ns}" | log_host
+		return 1
+	fi
+
+	return 0
+}
+
+vm_vsock_test() {
+	local ns=$1
+	local host=$2
+	local cid=$3
+	local port=$4
+	local rc
+
+	# log output and use pipefail to respect vsock_test errors
+	set -o pipefail
+	if [[ "${host}" != server ]]; then
+		vm_ssh "${ns}" -- ./vsock_test \
+			--mode=client \
+			--control-host="${host}" \
+			--peer-cid="${cid}" \
+			--control-port="${port}" \
+			2>&1 | log_guest
+		rc=$?
+	else
+		vm_ssh "${ns}" -- ./vsock_test \
+			--mode=server \
+			--peer-cid="${cid}" \
+			--control-port="${port}" \
+			2>&1 | log_guest &
+		rc=$?
+
+		if [[ $rc -ne 0 ]]; then
+			set +o pipefail
+			return $rc
+		fi
+
+		vm_wait_for_listener "${ns}" "${port}" "tcp"
+		rc=$?
+	fi
+	set +o pipefail
+
+	return $rc
+}
+
+host_vsock_test() {
+	local ns=$1
+	local host=$2
+	local cid=$3
+	local port=$4
+	shift 4
+	local extra_args=("$@")
+	local rc
+
+	local cmd="${VSOCK_TEST}"
+	if [[ "${ns}" != "init_ns" ]]; then
+		cmd="ip netns exec ${ns} ${cmd}"
+	fi
+
+	# log output and use pipefail to respect vsock_test errors
+	set -o pipefail
+	if [[ "${host}" != server ]]; then
+		${cmd} \
+			--mode=client \
+			--peer-cid="${cid}" \
+			--control-host="${host}" \
+			--control-port="${port}" \
+			"${extra_args[@]}" 2>&1 | log_host
+		rc=$?
+	else
+		${cmd} \
+			--mode=server \
+			--peer-cid="${cid}" \
+			--control-port="${port}" \
+			"${extra_args[@]}" 2>&1 | log_host &
+		rc=$?
+
+		if [[ $rc -ne 0 ]]; then
+			set +o pipefail
+			return $rc
+		fi
+
+		host_wait_for_listener "${ns}" "${port}" "tcp"
+		rc=$?
+	fi
+	set +o pipefail
+
+	return $rc
+}
+
+log() {
+	local redirect
+	local prefix
+
+	if [[ ${VERBOSE} -eq 0 ]]; then
+		redirect=/dev/null
+	else
+		redirect=/dev/stdout
+	fi
+
+	prefix="${LOG_PREFIX:-}"
+
+	if [[ "$#" -eq 0 ]]; then
+		if [[ -n "${prefix}" ]]; then
+			awk -v prefix="${prefix}" '{printf "%s: %s\n", prefix, $0}'
+		else
+			cat
+		fi
+	else
+		if [[ -n "${prefix}" ]]; then
+			echo "${prefix}: " "$@"
+		else
+			echo "$@"
+		fi
+	fi | tee -a "${LOG}" > "${redirect}"
+}
+
+log_host() {
+	LOG_PREFIX=host log "$@"
+}
+
+log_guest() {
+	LOG_PREFIX=guest log "$@"
+}
+
+ns_get_mode() {
+	local ns=$1
+
+	ip netns exec "${ns}" cat /proc/sys/net/vsock/ns_mode 2>/dev/null
+}
+
+test_ns_host_vsock_ns_mode_ok() {
+	for mode in "${NS_MODES[@]}"; do
+		local actual
+
+		actual=$(ns_get_mode "${mode}0")
+		if [[ "${actual}" != "${mode}" ]]; then
+			log_host "expected mode ${mode}, got ${actual}"
+			return "${KSFT_FAIL}"
+		fi
+	done
+
+	return "${KSFT_PASS}"
+}
+
+test_ns_diff_global_host_connect_to_global_vm_ok() {
+	local oops_before warn_before
+	local pids pid pidfile
+	local ns0 ns1 port
+	declare -a pids
+	local unixfile
+	ns0="global0"
+	ns1="global1"
+	port=1234
+	local rc
+
+	init_namespaces
+
+	pidfile="$(create_pidfile)"
+
+	if ! vm_start "${pidfile}" "${ns0}"; then
+		return "${KSFT_FAIL}"
+	fi
+
+	vm_wait_for_ssh "${ns0}"
+	oops_before=$(vm_dmesg_oops_count "${ns0}")
+	warn_before=$(vm_dmesg_warn_count "${ns0}")
+
+	unixfile=$(mktemp -u /tmp/XXXX.sock)
+	ip netns exec "${ns1}" \
+		socat TCP-LISTEN:"${TEST_HOST_PORT}",fork \
+			UNIX-CONNECT:"${unixfile}" &
+	pids+=($!)
+	host_wait_for_listener "${ns1}" "${TEST_HOST_PORT}" "tcp"
+
+	ip netns exec "${ns0}" socat UNIX-LISTEN:"${unixfile}",fork \
+		TCP-CONNECT:localhost:"${TEST_HOST_PORT}" &
+	pids+=($!)
+	host_wait_for_listener "${ns0}" "${unixfile}" "unix"
+
+	vm_vsock_test "${ns0}" "server" 2 "${TEST_GUEST_PORT}"
+	vm_wait_for_listener "${ns0}" "${TEST_GUEST_PORT}" "tcp"
+	host_vsock_test "${ns1}" "127.0.0.1" "${VSOCK_CID}" "${TEST_HOST_PORT}"
+	rc=$?
+
+	vm_dmesg_check "${pidfile}" "${ns0}" "${oops_before}" "${warn_before}"
+	dmesg_rc=$?
+
+	terminate_pids "${pids[@]}"
+	terminate_pidfiles "${pidfile}"
+
+	if [[ "${rc}" -ne 0 ]] || [[ "${dmesg_rc}" -ne 0 ]]; then
+		return "${KSFT_FAIL}"
+	fi
+
+	return "${KSFT_PASS}"
+}
+
+test_ns_diff_global_host_connect_to_local_vm_fails() {
+	local oops_before warn_before
+	local ns0="global0"
+	local ns1="local0"
+	local port=12345
+	local dmesg_rc
+	local pidfile
+	local result
+	local pid
+
+	init_namespaces
+
+	outfile=$(mktemp)
+
+	pidfile="$(create_pidfile)"
+	if ! vm_start "${pidfile}" "${ns1}"; then
+		log_host "failed to start vm (cid=${VSOCK_CID}, ns=${ns0})"
+		return "${KSFT_FAIL}"
+	fi
+
+	vm_wait_for_ssh "${ns1}"
+	oops_before=$(vm_dmesg_oops_count "${ns1}")
+	warn_before=$(vm_dmesg_warn_count "${ns1}")
+
+	vm_ssh "${ns1}" -- socat VSOCK-LISTEN:"${port}" STDOUT > "${outfile}" &
+	vm_wait_for_listener "${ns1}" "${port}" "vsock"
+	echo TEST | ip netns exec "${ns0}" \
+		socat STDIN VSOCK-CONNECT:"${VSOCK_CID}":"${port}" 2>/dev/null
+
+	vm_dmesg_check "${pidfile}" "${ns1}" "${oops_before}" "${warn_before}"
+	dmesg_rc=$?
+
+	terminate_pidfiles "${pidfile}"
+	result=$(cat "${outfile}")
+	rm -f "${outfile}"
+
+	if [[ "${result}" == "TEST" ]] || [[ "${dmesg_rc}" -ne 0 ]]; then
+		return "${KSFT_FAIL}"
+	fi
+
+	return "${KSFT_PASS}"
+}
+
+test_ns_diff_global_vm_connect_to_global_host_ok() {
+	local oops_before warn_before
+	local ns0="global0"
+	local ns1="global1"
+	local port=12345
+	local unixfile
+	local dmesg_rc
+	local pidfile
+	local pids
+	local rc
+
+	init_namespaces
+
+	declare -a pids
+
+	log_host "Setup socat bridge from ns ${ns0} to ns ${ns1} over port ${port}"
+
+	unixfile=$(mktemp -u /tmp/XXXX.sock)
+
+	ip netns exec "${ns0}" \
+		socat TCP-LISTEN:"${port}" UNIX-CONNECT:"${unixfile}" &
+	pids+=($!)
+	host_wait_for_listener "${ns0}" "${port}" "tcp"
+
+	ip netns exec "${ns1}" \
+		socat UNIX-LISTEN:"${unixfile}" TCP-CONNECT:127.0.0.1:"${port}" &
+	pids+=($!)
+	host_wait_for_listener "${ns1}" "${unixfile}" "unix"
+
+	log_host "Launching ${VSOCK_TEST} in ns ${ns1}"
+	host_vsock_test "${ns1}" "server" "${VSOCK_CID}" "${port}"
+
+	pidfile="$(create_pidfile)"
+	if ! vm_start "${pidfile}" "${ns0}"; then
+		log_host "failed to start vm (cid=${cid}, ns=${ns0})"
+		terminate_pids "${pids[@]}"
+		rm -f "${unixfile}"
+		return "${KSFT_FAIL}"
+	fi
+
+	vm_wait_for_ssh "${ns0}"
+
+	oops_before=$(vm_dmesg_oops_count "${ns0}")
+	warn_before=$(vm_dmesg_warn_count "${ns0}")
+
+	vm_vsock_test "${ns0}" "10.0.2.2" 2 "${port}"
+	rc=$?
+
+	vm_dmesg_check "${pidfile}" "${ns0}" "${oops_before}" "${warn_before}"
+	dmesg_rc=$?
+
+	terminate_pidfiles "${pidfile}"
+	terminate_pids "${pids[@]}"
+	rm -f "${unixfile}"
+
+	if [[ "${rc}" -ne 0 ]] || [[ "${dmesg_rc}" -ne 0 ]]; then
+		return "${KSFT_FAIL}"
+	fi
+
+	return "${KSFT_PASS}"
+
+}
+
+test_ns_diff_global_vm_connect_to_local_host_fails() {
+	local ns0="global0"
+	local ns1="local0"
+	local port=12345
+	local oops_before warn_before
+	local dmesg_rc
+	local pidfile
+	local result
+	local pid
+
+	init_namespaces
+
+	log_host "Launching socat in ns ${ns1}"
+	outfile=$(mktemp)
+
+	ip netns exec "${ns1}" socat VSOCK-LISTEN:"${port}" STDOUT &> "${outfile}" &
+	pid=$!
+	host_wait_for_listener "${ns1}" "${port}" "vsock"
+
+	pidfile="$(create_pidfile)"
+	if ! vm_start "${pidfile}" "${ns0}"; then
+		log_host "failed to start vm (cid=${cid}, ns=${ns0})"
+		terminate_pids "${pid}"
+		rm -f "${outfile}"
+		return "${KSFT_FAIL}"
+	fi
+
+	vm_wait_for_ssh "${ns0}"
+
+	oops_before=$(vm_dmesg_oops_count "${ns0}")
+	warn_before=$(vm_dmesg_warn_count "${ns0}")
+
+	vm_ssh "${ns0}" -- \
+		bash -c "echo TEST | socat STDIN VSOCK-CONNECT:2:${port}" 2>&1 | log_guest
+
+	vm_dmesg_check "${pidfile}" "${ns0}" "${oops_before}" "${warn_before}"
+	dmesg_rc=$?
+
+	terminate_pidfiles "${pidfile}"
+	terminate_pids "${pid}"
+
+	result=$(cat "${outfile}")
+	rm -f "${outfile}"
+
+	if [[ "${result}" != TEST ]] && [[ "${dmesg_rc}" -eq 0 ]]; then
+		return "${KSFT_PASS}"
+	fi
+
+	return "${KSFT_FAIL}"
+}
+
+test_ns_diff_local_host_connect_to_local_vm_fails() {
+	local ns0="local0"
+	local ns1="local1"
+	local port=12345
+	local oops_before warn_before
+	local dmesg_rc
+	local pidfile
+	local result
+	local pid
+
+	init_namespaces
+
+	outfile=$(mktemp)
+
+	pidfile="$(create_pidfile)"
+	if ! vm_start "${pidfile}" "${ns1}"; then
+		log_host "failed to start vm (cid=${cid}, ns=${ns0})"
+		return "${KSFT_FAIL}"
+	fi
+
+	vm_wait_for_ssh "${ns1}"
+	oops_before=$(vm_dmesg_oops_count "${ns1}")
+	warn_before=$(vm_dmesg_warn_count "${ns1}")
+
+	vm_ssh "${ns1}" -- socat VSOCK-LISTEN:"${port}" STDOUT > "${outfile}" &
+	vm_wait_for_listener "${ns1}" "${port}" "vsock"
+
+	echo TEST | ip netns exec "${ns0}" \
+		socat STDIN VSOCK-CONNECT:"${VSOCK_CID}":"${port}" 2>/dev/null
+
+	vm_dmesg_check "${pidfile}" "${ns1}" "${oops_before}" "${warn_before}"
+	dmesg_rc=$?
+
+	terminate_pidfiles "${pidfile}"
+
+	result=$(cat "${outfile}")
+	rm -f "${outfile}"
+
+	if [[ "${result}" != TEST ]] && [[ "${dmesg_rc}" -eq 0 ]]; then
+		return "${KSFT_PASS}"
+	fi
+
+	return "${KSFT_FAIL}"
+}
+
+test_ns_diff_local_vm_connect_to_local_host_fails() {
+	local oops_before warn_before
+	local ns0="local0"
+	local ns1="local1"
+	local port=12345
+	local dmesg_rc
+	local pidfile
+	local result
+	local pid
+
+	init_namespaces
+
+	log_host "Launching socat in ns ${ns1}"
+	outfile=$(mktemp)
+	ip netns exec "${ns1}" socat VSOCK-LISTEN:"${port}" STDOUT &> "${outfile}" &
+	pid=$!
+	host_wait_for_listener "${ns1}" "${port}" "vsock"
+
+	pidfile="$(create_pidfile)"
+	if ! vm_start "${pidfile}" "${ns0}"; then
+		log_host "failed to start vm (cid=${cid}, ns=${ns0})"
+		rm -f "${outfile}"
+		return "${KSFT_FAIL}"
+	fi
+
+	vm_wait_for_ssh "${ns0}"
+	oops_before=$(vm_dmesg_oops_count "${ns0}")
+	warn_before=$(vm_dmesg_warn_count "${ns0}")
+
+	vm_ssh "${ns0}" -- \
+		bash -c "echo TEST | socat STDIN VSOCK-CONNECT:2:${port}" 2>&1 | log_guest
+
+	vm_dmesg_check "${pidfile}" "${ns0}" "${oops_before}" "${warn_before}"
+	dmesg_rc=$?
+
+	terminate_pidfiles "${pidfile}"
+	terminate_pids "${pid}"
+
+	result=$(cat "${outfile}")
+	rm -f "${outfile}"
+
+	if [[ "${result}" != TEST ]] && [[ "${dmesg_rc}" -eq 0 ]]; then
+		return "${KSFT_PASS}"
+	fi
+
+	return "${KSFT_FAIL}"
+}
+
+__test_loopback_two_netns() {
+	local ns0=$1
+	local ns1=$2
+	local port=12345
+	local result
+	local pid
+
+	modprobe vsock_loopback &> /dev/null || :
+
+	log_host "Launching socat in ns ${ns1}"
+	outfile=$(mktemp)
+
+	ip netns exec "${ns1}" socat VSOCK-LISTEN:"${port}" STDOUT > "${outfile}" 2>/dev/null &
+	pid=$!
+	host_wait_for_listener "${ns1}" "${port}" "vsock"
+
+	log_host "Launching socat in ns ${ns0}"
+	echo TEST | ip netns exec "${ns0}" socat STDIN VSOCK-CONNECT:1:"${port}" 2>/dev/null
+	terminate_pids "${pid}"
+
+	result=$(cat "${outfile}")
+	rm -f "${outfile}"
+
+	if [[ "${result}" == TEST ]]; then
+		return 0
+	fi
+
+	return 1
+}
+
+test_ns_diff_global_to_local_loopback_local_fails() {
+	init_namespaces
+
+	if ! __test_loopback_two_netns "global0" "local0"; then
+		return "${KSFT_PASS}"
+	fi
+
+	return "${KSFT_FAIL}"
+}
+
+test_ns_diff_local_to_global_loopback_fails() {
+	init_namespaces
+
+	if ! __test_loopback_two_netns "local0" "global0"; then
+		return "${KSFT_PASS}"
+	fi
+
+	return "${KSFT_FAIL}"
+}
+
+test_ns_diff_local_to_local_loopback_fails() {
+	init_namespaces
+
+	if ! __test_loopback_two_netns "local0" "local1"; then
+		return "${KSFT_PASS}"
+	fi
+
+	return "${KSFT_FAIL}"
+}
+
+test_ns_diff_global_to_global_loopback_ok() {
+	init_namespaces
+
+	if __test_loopback_two_netns "global0" "global1"; then
+		return "${KSFT_PASS}"
+	fi
+
+	return "${KSFT_FAIL}"
+}
+
+test_ns_same_local_loopback_ok() {
+	init_namespaces
+
+	if __test_loopback_two_netns "local0" "local0"; then
+		return "${KSFT_PASS}"
+	fi
+
+	return "${KSFT_FAIL}"
+}
+
+test_ns_same_local_host_connect_to_local_vm_ok() {
+	local oops_before warn_before
+	local ns="local0"
+	local port=1234
+	local dmesg_rc
+	local pidfile
+	local rc
+
+	init_namespaces
+
+	pidfile="$(create_pidfile)"
+
+	if ! vm_start "${pidfile}" "${ns}"; then
+		return "${KSFT_FAIL}"
+	fi
+
+	vm_wait_for_ssh "${ns}"
+	oops_before=$(vm_dmesg_oops_count "${ns}")
+	warn_before=$(vm_dmesg_warn_count "${ns}")
+
+	vm_vsock_test "${ns}" "server" 2 "${TEST_GUEST_PORT}"
+
+	# Skip test 29 (transport release use-after-free): This test attempts
+	# binding both G2H and H2G CIDs. Because virtio-vsock (G2H) doesn't
+	# support local namespaces the test will fail when
+	# transport_g2h->stream_allow() returns false. This edge case only
+	# happens for vsock_test in client mode on the host in a local
+	# namespace. This is a false positive.
+	host_vsock_test "${ns}" "127.0.0.1" "${VSOCK_CID}" "${TEST_HOST_PORT}" --skip=29
+	rc=$?
+
+	vm_dmesg_check "${pidfile}" "${ns}" "${oops_before}" "${warn_before}"
+	dmesg_rc=$?
+
+	terminate_pidfiles "${pidfile}"
+
+	if [[ "${rc}" -ne 0 ]] || [[ "${dmesg_rc}" -ne 0 ]]; then
+		return "${KSFT_FAIL}"
+	fi
+
+	return "${KSFT_PASS}"
+}
+
+test_ns_same_local_vm_connect_to_local_host_ok() {
+	local oops_before warn_before
+	local ns="local0"
+	local port=1234
+	local dmesg_rc
+	local pidfile
+	local rc
+
+	init_namespaces
+
+	pidfile="$(create_pidfile)"
+
+	if ! vm_start "${pidfile}" "${ns}"; then
+		return "${KSFT_FAIL}"
+	fi
+
+	vm_wait_for_ssh "${ns}"
+	oops_before=$(vm_dmesg_oops_count "${ns}")
+	warn_before=$(vm_dmesg_warn_count "${ns}")
+
+	host_vsock_test "${ns}" "server" "${VSOCK_CID}" "${port}"
+	vm_vsock_test "${ns}" "10.0.2.2" 2 "${port}"
+	rc=$?
+
+	vm_dmesg_check "${pidfile}" "${ns}" "${oops_before}" "${warn_before}"
+	dmesg_rc=$?
+
+	terminate_pidfiles "${pidfile}"
+
+	if [[ "${rc}" -ne 0 ]] || [[ "${dmesg_rc}" -ne 0 ]]; then
+		return "${KSFT_FAIL}"
+	fi
+
+	return "${KSFT_PASS}"
+}
+
+namespaces_can_boot_same_cid() {
+	local ns0=$1
+	local ns1=$2
+	local pidfile1 pidfile2
+	local rc
+
+	pidfile1="$(create_pidfile)"
+
+	# The first VM should be able to start. If it can't then we have
+	# problems and need to return non-zero.
+	if ! vm_start "${pidfile1}" "${ns0}"; then
+		return 1
+	fi
+
+	pidfile2="$(create_pidfile)"
+	vm_start "${pidfile2}" "${ns1}"
+	rc=$?
+	terminate_pidfiles "${pidfile1}" "${pidfile2}"
+
+	return "${rc}"
+}
+
+test_ns_global_same_cid_fails() {
+	init_namespaces
+
+	if namespaces_can_boot_same_cid "global0" "global1"; then
+		return "${KSFT_FAIL}"
+	fi
+
+	return "${KSFT_PASS}"
+}
+
+test_ns_local_global_same_cid_ok() {
+	init_namespaces
+
+	if namespaces_can_boot_same_cid "local0" "global0"; then
+		return "${KSFT_PASS}"
+	fi
+
+	return "${KSFT_FAIL}"
+}
+
+test_ns_global_local_same_cid_ok() {
+	init_namespaces
+
+	if namespaces_can_boot_same_cid "global0" "local0"; then
+		return "${KSFT_PASS}"
+	fi
+
+	return "${KSFT_FAIL}"
+}
+
+test_ns_local_same_cid_ok() {
+	init_namespaces
+
+	if namespaces_can_boot_same_cid "local0" "local1"; then
+		return "${KSFT_PASS}"
+	fi
+
+	return "${KSFT_FAIL}"
+}
+
+test_ns_host_vsock_child_ns_mode_ok() {
+	local rc="${KSFT_PASS}"
+
+	for mode in "${NS_MODES[@]}"; do
+		local ns="${mode}0"
+
+		if echo "${mode}" 2>/dev/null > /proc/sys/net/vsock/ns_mode; then
+			log_host "ns_mode should be read-only but write succeeded"
+			rc="${KSFT_FAIL}"
+			continue
+		fi
+
+		if ! echo "${mode}" | ip netns exec "${ns}" \
+			tee /proc/sys/net/vsock/child_ns_mode &>/dev/null; then
+			rc="${KSFT_FAIL}"
+			continue
+		fi
+	done
+
+	return "${rc}"
+}
+
+test_vm_server_host_client() {
+	if ! vm_vsock_test "init_ns" "server" 2 "${TEST_GUEST_PORT}"; then
+		return "${KSFT_FAIL}"
+	fi
+
+	if ! host_vsock_test "init_ns" "127.0.0.1" "${VSOCK_CID}" "${TEST_HOST_PORT}"; then
+		return "${KSFT_FAIL}"
+	fi
+
+	return "${KSFT_PASS}"
+}
+
+test_vm_client_host_server() {
+	if ! host_vsock_test "init_ns" "server" "${VSOCK_CID}" "${TEST_HOST_PORT_LISTENER}"; then
+		return "${KSFT_FAIL}"
+	fi
+
+	if ! vm_vsock_test "init_ns" "10.0.2.2" 2 "${TEST_HOST_PORT_LISTENER}"; then
+		return "${KSFT_FAIL}"
+	fi
+
+	return "${KSFT_PASS}"
+}
+
+test_vm_loopback() {
+	local port=60000 # non-forwarded local port
+
+	vm_ssh "init_ns" -- modprobe vsock_loopback &> /dev/null || :
+
+	if ! vm_vsock_test "init_ns" "server" 1 "${port}"; then
+		return "${KSFT_FAIL}"
+	fi
+
+
+	if ! vm_vsock_test "init_ns" "127.0.0.1" 1 "${port}"; then
+		return "${KSFT_FAIL}"
+	fi
+
+	return "${KSFT_PASS}"
+}
+
+check_ns_delete_doesnt_break_connection() {
+	local pipefile pidfile outfile
+	local ns0="global0"
+	local ns1="global1"
+	local port=12345
+	local pids=()
+	local rc=0
+
+	init_namespaces
+
+	pidfile="$(create_pidfile)"
+	if ! vm_start "${pidfile}" "${ns0}"; then
+		return "${KSFT_FAIL}"
+	fi
+	vm_wait_for_ssh "${ns0}"
+
+	outfile=$(mktemp)
+	vm_ssh "${ns0}" -- \
+		socat VSOCK-LISTEN:"${port}",fork STDOUT > "${outfile}" 2>/dev/null &
+	pids+=($!)
+	vm_wait_for_listener "${ns0}" "${port}" "vsock"
+
+	# We use a pipe here so that we can echo into the pipe instead of using
+	# socat and a unix socket file. We just need a name for the pipe (not a
+	# regular file) so use -u.
+	pipefile=$(mktemp -u /tmp/vmtest_pipe_XXXX)
+	ip netns exec "${ns1}" \
+		socat PIPE:"${pipefile}" VSOCK-CONNECT:"${VSOCK_CID}":"${port}" &
+	pids+=($!)
+
+	timeout "${WAIT_PERIOD}" \
+		bash -c 'while [[ ! -e '"${pipefile}"' ]]; do sleep 1; done; exit 0'
+
+	if [[ "$1" == "vm" ]]; then
+		ip netns del "${ns0}"
+	elif [[ "$1" == "host" ]]; then
+		ip netns del "${ns1}"
+	elif [[ "$1" == "both" ]]; then
+		ip netns del "${ns0}"
+		ip netns del "${ns1}"
+	fi
+
+	echo "TEST" > "${pipefile}"
+
+	timeout "${WAIT_PERIOD}" \
+		bash -c 'while [[ ! -s '"${outfile}"' ]]; do sleep 1; done; exit 0'
+
+	if grep -q "TEST" "${outfile}"; then
+		rc="${KSFT_PASS}"
+	else
+		rc="${KSFT_FAIL}"
+	fi
+
+	terminate_pidfiles "${pidfile}"
+	terminate_pids "${pids[@]}"
+	rm -f "${outfile}" "${pipefile}"
+
+	return "${rc}"
+}
+
+test_ns_delete_vm_ok() {
+	check_ns_delete_doesnt_break_connection "vm"
+}
+
+test_ns_delete_host_ok() {
+	check_ns_delete_doesnt_break_connection "host"
+}
+
+test_ns_delete_both_ok() {
+	check_ns_delete_doesnt_break_connection "both"
+}
+
+shared_vm_test() {
+	local tname
+
+	tname="${1}"
+
+	for testname in "${USE_SHARED_VM[@]}"; do
+		if [[ "${tname}" == "${testname}" ]]; then
+			return 0
+		fi
+	done
+
+	return 1
+}
+
+shared_vm_tests_requested() {
+	for arg in "$@"; do
+		if shared_vm_test "${arg}"; then
+			return 0
+		fi
+	done
+
+	return 1
+}
+
+run_shared_vm_tests() {
+	local arg
+
+	for arg in "$@"; do
+		if ! shared_vm_test "${arg}"; then
+			continue
+		fi
+
+		if ! check_netns "${arg}"; then
+			check_result "${KSFT_SKIP}" "${arg}"
+			continue
+		fi
+
+		run_shared_vm_test "${arg}"
+		check_result "$?" "${arg}"
+	done
+}
+
+run_shared_vm_test() {
+	local host_oops_cnt_before
+	local host_warn_cnt_before
+	local vm_oops_cnt_before
+	local vm_warn_cnt_before
+	local host_oops_cnt_after
+	local host_warn_cnt_after
+	local vm_oops_cnt_after
+	local vm_warn_cnt_after
+	local name
+	local rc
+
+	host_oops_cnt_before=$(dmesg | grep -c -i 'Oops')
+	host_warn_cnt_before=$(dmesg --level=warn | grep -c -i 'vsock')
+	vm_oops_cnt_before=$(vm_dmesg_oops_count "init_ns")
+	vm_warn_cnt_before=$(vm_dmesg_warn_count "init_ns")
+
+	name=$(echo "${1}" | awk '{ print $1 }')
+	eval test_"${name}"
+	rc=$?
+
+	host_oops_cnt_after=$(dmesg | grep -i 'Oops' | wc -l)
+	if [[ ${host_oops_cnt_after} -gt ${host_oops_cnt_before} ]]; then
+		echo "FAIL: kernel oops detected on host" | log_host
+		rc=$KSFT_FAIL
+	fi
+
+	host_warn_cnt_after=$(dmesg --level=warn | grep -c -i 'vsock')
+	if [[ ${host_warn_cnt_after} -gt ${host_warn_cnt_before} ]]; then
+		echo "FAIL: kernel warning detected on host" | log_host
+		rc=$KSFT_FAIL
+	fi
+
+	vm_oops_cnt_after=$(vm_dmesg_oops_count "init_ns")
+	if [[ ${vm_oops_cnt_after} -gt ${vm_oops_cnt_before} ]]; then
+		echo "FAIL: kernel oops detected on vm" | log_host
+		rc=$KSFT_FAIL
+	fi
+
+	vm_warn_cnt_after=$(vm_dmesg_warn_count "init_ns")
+	if [[ ${vm_warn_cnt_after} -gt ${vm_warn_cnt_before} ]]; then
+		echo "FAIL: kernel warning detected on vm" | log_host
+		rc=$KSFT_FAIL
+	fi
+
+	return "${rc}"
+}
+
+run_ns_tests() {
+	for arg in "${ARGS[@]}"; do
+		if shared_vm_test "${arg}"; then
+			continue
+		fi
+
+		if ! check_netns "${arg}"; then
+			check_result "${KSFT_SKIP}" "${arg}"
+			continue
+		fi
+
+		add_namespaces
+
+		name=$(echo "${arg}" | awk '{ print $1 }')
+		log_host "Executing test_${name}"
+
+		host_oops_before=$(dmesg 2>/dev/null | grep -c -i 'Oops')
+		host_warn_before=$(dmesg --level=warn 2>/dev/null | grep -c -i 'vsock')
+		eval test_"${name}"
+		rc=$?
+
+		host_oops_after=$(dmesg 2>/dev/null | grep -c -i 'Oops')
+		if [[ "${host_oops_after}" -gt "${host_oops_before}" ]]; then
+			echo "FAIL: kernel oops detected on host" | log_host
+			check_result "${KSFT_FAIL}" "${name}"
+			del_namespaces
+			continue
+		fi
+
+		host_warn_after=$(dmesg --level=warn 2>/dev/null | grep -c -i 'vsock')
+		if [[ "${host_warn_after}" -gt "${host_warn_before}" ]]; then
+			echo "FAIL: kernel warning detected on host" | log_host
+			check_result "${KSFT_FAIL}" "${name}"
+			del_namespaces
+			continue
+		fi
+
+		check_result "${rc}" "${name}"
+
+		del_namespaces
+	done
+}
+
+BUILD=0
+QEMU="qemu-system-$(uname -m)"
+
+while getopts :hvsq:b o
+do
+	case $o in
+	v) VERBOSE=1;;
+	b) BUILD=1;;
+	q) QEMU=$OPTARG;;
+	h|*) usage;;
+	esac
+done
+shift $((OPTIND-1))
+
+trap cleanup EXIT
+
+if [[ ${#} -eq 0 ]]; then
+	ARGS=("${TEST_NAMES[@]}")
+else
+	ARGS=("$@")
+fi
+
+check_args "${ARGS[@]}"
+check_deps
+check_vng
+check_socat
+handle_build
+setup_home
+
+echo "1..${#ARGS[@]}"
+
+cnt_pass=0
+cnt_fail=0
+cnt_skip=0
+cnt_total=0
+
+if shared_vm_tests_requested "${ARGS[@]}"; then
+	log_host "Booting up VM"
+	pidfile="$(create_pidfile)"
+	vm_start "${pidfile}" "init_ns"
+	vm_wait_for_ssh "init_ns"
+	log_host "VM booted up"
+
+	run_shared_vm_tests "${ARGS[@]}"
+	terminate_pidfiles "${pidfile}"
+fi
+
+run_ns_tests "${ARGS[@]}"
+
+echo "SUMMARY: PASS=${cnt_pass} SKIP=${cnt_skip} FAIL=${cnt_fail}"
+echo "Log: ${LOG}"
+
+if [ $((cnt_pass + cnt_skip)) -eq ${cnt_total} ]; then
+	exit "$KSFT_PASS"
+else
+	exit "$KSFT_FAIL"
+fi