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
  ...

10 files changed, 2378 insertions, 0 deletions

diff --git a/tools/testing/selftests/memfd/.gitignore b/tools/testing/selftests/memfd/.gitignore
new file mode 100644
index 000000000..dd9a051f6
--- /dev/null
+++ b/tools/testing/selftests/memfd/.gitignore
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0-only
+fuse_mnt
+fuse_test
+memfd_test
+memfd-test-file
diff --git a/tools/testing/selftests/memfd/Makefile b/tools/testing/selftests/memfd/Makefile
new file mode 100644
index 000000000..163b6f686
--- /dev/null
+++ b/tools/testing/selftests/memfd/Makefile
@@ -0,0 +1,28 @@
+# SPDX-License-Identifier: GPL-2.0
+CFLAGS += -D_FILE_OFFSET_BITS=64
+CFLAGS += $(KHDR_INCLUDES)
+
+TEST_GEN_PROGS := memfd_test
+TEST_PROGS := run_fuse_test.sh run_hugetlbfs_test.sh
+TEST_GEN_FILES := fuse_test fuse_mnt
+
+VAR_CFLAGS := $(shell pkg-config fuse --cflags 2>/dev/null)
+ifeq ($(VAR_CFLAGS),)
+VAR_CFLAGS := -D_FILE_OFFSET_BITS=64 -I/usr/include/fuse
+endif
+
+VAR_LDLIBS := $(shell pkg-config fuse --libs 2>/dev/null)
+ifeq ($(VAR_LDLIBS),)
+VAR_LDLIBS := -lfuse -pthread
+endif
+
+fuse_mnt.o: CFLAGS += $(VAR_CFLAGS)
+
+include ../lib.mk
+
+$(OUTPUT)/fuse_mnt: LDLIBS += $(VAR_LDLIBS)
+
+$(OUTPUT)/memfd_test: memfd_test.c common.c
+$(OUTPUT)/fuse_test: fuse_test.c common.c
+
+EXTRA_CLEAN = $(OUTPUT)/common.o
diff --git a/tools/testing/selftests/memfd/common.c b/tools/testing/selftests/memfd/common.c
new file mode 100644
index 000000000..8eb3d75f6
--- /dev/null
+++ b/tools/testing/selftests/memfd/common.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#define __EXPORTED_HEADERS__
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <linux/fcntl.h>
+#include <linux/memfd.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+
+#include "common.h"
+
+int hugetlbfs_test = 0;
+
+/*
+ * Copied from mlock2-tests.c
+ */
+unsigned long default_huge_page_size(void)
+{
+	unsigned long hps = 0;
+	char *line = NULL;
+	size_t linelen = 0;
+	FILE *f = fopen("/proc/meminfo", "r");
+
+	if (!f)
+		return 0;
+	while (getline(&line, &linelen, f) > 0) {
+		if (sscanf(line, "Hugepagesize:       %lu kB", &hps) == 1) {
+			hps <<= 10;
+			break;
+		}
+	}
+
+	free(line);
+	fclose(f);
+	return hps;
+}
+
+int sys_memfd_create(const char *name, unsigned int flags)
+{
+	if (hugetlbfs_test)
+		flags |= MFD_HUGETLB;
+
+	return syscall(__NR_memfd_create, name, flags);
+}
diff --git a/tools/testing/selftests/memfd/common.h b/tools/testing/selftests/memfd/common.h
new file mode 100644
index 000000000..522d2c630
--- /dev/null
+++ b/tools/testing/selftests/memfd/common.h
@@ -0,0 +1,9 @@
+#ifndef COMMON_H_
+#define COMMON_H_
+
+extern int hugetlbfs_test;
+
+unsigned long default_huge_page_size(void);
+int sys_memfd_create(const char *name, unsigned int flags);
+
+#endif
diff --git a/tools/testing/selftests/memfd/config b/tools/testing/selftests/memfd/config
new file mode 100644
index 000000000..835c7f4da
--- /dev/null
+++ b/tools/testing/selftests/memfd/config
@@ -0,0 +1 @@
+CONFIG_FUSE_FS=m
diff --git a/tools/testing/selftests/memfd/fuse_mnt.c b/tools/testing/selftests/memfd/fuse_mnt.c
new file mode 100644
index 000000000..6936f2a00
--- /dev/null
+++ b/tools/testing/selftests/memfd/fuse_mnt.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * memfd test file-system
+ * This file uses FUSE to create a dummy file-system with only one file /memfd.
+ * This file is read-only and takes 1s per read.
+ *
+ * This file-system is used by the memfd test-cases to force the kernel to pin
+ * pages during reads(). Due to the 1s delay of this file-system, this is a
+ * nice way to test race-conditions against get_user_pages() in the kernel.
+ *
+ * We use direct_io==1 to force the kernel to use direct-IO for this
+ * file-system.
+ */
+
+#define FUSE_USE_VERSION 26
+
+#include <fuse.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+static const char memfd_content[] = "memfd-example-content";
+static const char memfd_path[] = "/memfd";
+
+static int memfd_getattr(const char *path, struct stat *st)
+{
+	memset(st, 0, sizeof(*st));
+
+	if (!strcmp(path, "/")) {
+		st->st_mode = S_IFDIR | 0755;
+		st->st_nlink = 2;
+	} else if (!strcmp(path, memfd_path)) {
+		st->st_mode = S_IFREG | 0444;
+		st->st_nlink = 1;
+		st->st_size = strlen(memfd_content);
+	} else {
+		return -ENOENT;
+	}
+
+	return 0;
+}
+
+static int memfd_readdir(const char *path,
+			 void *buf,
+			 fuse_fill_dir_t filler,
+			 off_t offset,
+			 struct fuse_file_info *fi)
+{
+	if (strcmp(path, "/"))
+		return -ENOENT;
+
+	filler(buf, ".", NULL, 0);
+	filler(buf, "..", NULL, 0);
+	filler(buf, memfd_path + 1, NULL, 0);
+
+	return 0;
+}
+
+static int memfd_open(const char *path, struct fuse_file_info *fi)
+{
+	if (strcmp(path, memfd_path))
+		return -ENOENT;
+
+	if ((fi->flags & 3) != O_RDONLY)
+		return -EACCES;
+
+	/* force direct-IO */
+	fi->direct_io = 1;
+
+	return 0;
+}
+
+static int memfd_read(const char *path,
+		      char *buf,
+		      size_t size,
+		      off_t offset,
+		      struct fuse_file_info *fi)
+{
+	size_t len;
+
+	if (strcmp(path, memfd_path) != 0)
+		return -ENOENT;
+
+	sleep(1);
+
+	len = strlen(memfd_content);
+	if (offset < len) {
+		if (offset + size > len)
+			size = len - offset;
+
+		memcpy(buf, memfd_content + offset, size);
+	} else {
+		size = 0;
+	}
+
+	return size;
+}
+
+static struct fuse_operations memfd_ops = {
+	.getattr	= memfd_getattr,
+	.readdir	= memfd_readdir,
+	.open		= memfd_open,
+	.read		= memfd_read,
+};
+
+int main(int argc, char *argv[])
+{
+	return fuse_main(argc, argv, &memfd_ops, NULL);
+}
diff --git a/tools/testing/selftests/memfd/fuse_test.c b/tools/testing/selftests/memfd/fuse_test.c
new file mode 100644
index 000000000..510056c1b
--- /dev/null
+++ b/tools/testing/selftests/memfd/fuse_test.c
@@ -0,0 +1,331 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * memfd GUP test-case
+ * This tests memfd interactions with get_user_pages(). We require the
+ * fuse_mnt.c program to provide a fake direct-IO FUSE mount-point for us. This
+ * file-system delays _all_ reads by 1s and forces direct-IO. This means, any
+ * read() on files in that file-system will pin the receive-buffer pages for at
+ * least 1s via get_user_pages().
+ *
+ * We use this trick to race ADD_SEALS against a write on a memfd object. The
+ * ADD_SEALS must fail if the memfd pages are still pinned. Note that we use
+ * the read() syscall with our memory-mapped memfd object as receive buffer to
+ * force the kernel to write into our memfd object.
+ */
+
+#define _GNU_SOURCE
+#define __EXPORTED_HEADERS__
+
+#include <errno.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <linux/falloc.h>
+#include <fcntl.h>
+#include <linux/memfd.h>
+#include <linux/types.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "common.h"
+
+#define MFD_DEF_SIZE 8192
+#define STACK_SIZE 65536
+
+static size_t mfd_def_size = MFD_DEF_SIZE;
+
+static int mfd_assert_new(const char *name, loff_t sz, unsigned int flags)
+{
+	int r, fd;
+
+	fd = sys_memfd_create(name, flags);
+	if (fd < 0) {
+		printf("memfd_create(\"%s\", %u) failed: %m\n",
+		       name, flags);
+		abort();
+	}
+
+	r = ftruncate(fd, sz);
+	if (r < 0) {
+		printf("ftruncate(%llu) failed: %m\n", (unsigned long long)sz);
+		abort();
+	}
+
+	return fd;
+}
+
+static __u64 mfd_assert_get_seals(int fd)
+{
+	long r;
+
+	r = fcntl(fd, F_GET_SEALS);
+	if (r < 0) {
+		printf("GET_SEALS(%d) failed: %m\n", fd);
+		abort();
+	}
+
+	return r;
+}
+
+static void mfd_assert_has_seals(int fd, __u64 seals)
+{
+	__u64 s;
+
+	s = mfd_assert_get_seals(fd);
+	if (s != seals) {
+		printf("%llu != %llu = GET_SEALS(%d)\n",
+		       (unsigned long long)seals, (unsigned long long)s, fd);
+		abort();
+	}
+}
+
+static void mfd_assert_add_seals(int fd, __u64 seals)
+{
+	long r;
+	__u64 s;
+
+	s = mfd_assert_get_seals(fd);
+	r = fcntl(fd, F_ADD_SEALS, seals);
+	if (r < 0) {
+		printf("ADD_SEALS(%d, %llu -> %llu) failed: %m\n",
+		       fd, (unsigned long long)s, (unsigned long long)seals);
+		abort();
+	}
+}
+
+static int mfd_busy_add_seals(int fd, __u64 seals)
+{
+	long r;
+	__u64 s;
+
+	r = fcntl(fd, F_GET_SEALS);
+	if (r < 0)
+		s = 0;
+	else
+		s = r;
+
+	r = fcntl(fd, F_ADD_SEALS, seals);
+	if (r < 0 && errno != EBUSY) {
+		printf("ADD_SEALS(%d, %llu -> %llu) didn't fail as expected with EBUSY: %m\n",
+		       fd, (unsigned long long)s, (unsigned long long)seals);
+		abort();
+	}
+
+	return r;
+}
+
+static void *mfd_assert_mmap_shared(int fd)
+{
+	void *p;
+
+	p = mmap(NULL,
+		 mfd_def_size,
+		 PROT_READ | PROT_WRITE,
+		 MAP_SHARED,
+		 fd,
+		 0);
+	if (p == MAP_FAILED) {
+		printf("mmap() failed: %m\n");
+		abort();
+	}
+
+	return p;
+}
+
+static void *mfd_assert_mmap_private(int fd)
+{
+	void *p;
+
+	p = mmap(NULL,
+		 mfd_def_size,
+		 PROT_READ | PROT_WRITE,
+		 MAP_PRIVATE,
+		 fd,
+		 0);
+	if (p == MAP_FAILED) {
+		printf("mmap() failed: %m\n");
+		abort();
+	}
+
+	return p;
+}
+
+static int global_mfd = -1;
+static void *global_p = NULL;
+
+static int sealing_thread_fn(void *arg)
+{
+	int r;
+
+	/*
+	 * This thread first waits 200ms so any pending operation in the parent
+	 * is correctly started. After that, it tries to seal @global_mfd as
+	 * SEAL_WRITE. This _must_ fail as the parent thread has a read() into
+	 * that memory mapped object still ongoing.
+	 * We then wait one more second and try sealing again. This time it
+	 * must succeed as there shouldn't be anyone else pinning the pages.
+	 */
+
+	/* wait 200ms for FUSE-request to be active */
+	usleep(200000);
+
+	/* unmount mapping before sealing to avoid i_mmap_writable failures */
+	munmap(global_p, mfd_def_size);
+
+	/* Try sealing the global file; expect EBUSY or success. Current
+	 * kernels will never succeed, but in the future, kernels might
+	 * implement page-replacements or other fancy ways to avoid racing
+	 * writes. */
+	r = mfd_busy_add_seals(global_mfd, F_SEAL_WRITE);
+	if (r >= 0) {
+		printf("HURRAY! This kernel fixed GUP races!\n");
+	} else {
+		/* wait 1s more so the FUSE-request is done */
+		sleep(1);
+
+		/* try sealing the global file again */
+		mfd_assert_add_seals(global_mfd, F_SEAL_WRITE);
+	}
+
+	return 0;
+}
+
+static pid_t spawn_sealing_thread(void)
+{
+	uint8_t *stack;
+	pid_t pid;
+
+	stack = malloc(STACK_SIZE);
+	if (!stack) {
+		printf("malloc(STACK_SIZE) failed: %m\n");
+		abort();
+	}
+
+	pid = clone(sealing_thread_fn,
+		    stack + STACK_SIZE,
+		    SIGCHLD | CLONE_FILES | CLONE_FS | CLONE_VM,
+		    NULL);
+	if (pid < 0) {
+		printf("clone() failed: %m\n");
+		abort();
+	}
+
+	return pid;
+}
+
+static void join_sealing_thread(pid_t pid)
+{
+	waitpid(pid, NULL, 0);
+}
+
+int main(int argc, char **argv)
+{
+	char *zero;
+	int fd, mfd, r;
+	void *p;
+	int was_sealed;
+	pid_t pid;
+
+	if (argc < 2) {
+		printf("error: please pass path to file in fuse_mnt mount-point\n");
+		abort();
+	}
+
+	if (argc >= 3) {
+		if (!strcmp(argv[2], "hugetlbfs")) {
+			unsigned long hpage_size = default_huge_page_size();
+
+			if (!hpage_size) {
+				printf("Unable to determine huge page size\n");
+				abort();
+			}
+
+			hugetlbfs_test = 1;
+			mfd_def_size = hpage_size * 2;
+		} else {
+			printf("Unknown option: %s\n", argv[2]);
+			abort();
+		}
+	}
+
+	zero = calloc(sizeof(*zero), mfd_def_size);
+
+	/* open FUSE memfd file for GUP testing */
+	printf("opening: %s\n", argv[1]);
+	fd = open(argv[1], O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		printf("cannot open(\"%s\"): %m\n", argv[1]);
+		abort();
+	}
+
+	/* create new memfd-object */
+	mfd = mfd_assert_new("kern_memfd_fuse",
+			     mfd_def_size,
+			     MFD_CLOEXEC | MFD_ALLOW_SEALING);
+
+	/* mmap memfd-object for writing */
+	p = mfd_assert_mmap_shared(mfd);
+
+	/* pass mfd+mapping to a separate sealing-thread which tries to seal
+	 * the memfd objects with SEAL_WRITE while we write into it */
+	global_mfd = mfd;
+	global_p = p;
+	pid = spawn_sealing_thread();
+
+	/* Use read() on the FUSE file to read into our memory-mapped memfd
+	 * object. This races the other thread which tries to seal the
+	 * memfd-object.
+	 * If @fd is on the memfd-fake-FUSE-FS, the read() is delayed by 1s.
+	 * This guarantees that the receive-buffer is pinned for 1s until the
+	 * data is written into it. The racing ADD_SEALS should thus fail as
+	 * the pages are still pinned. */
+	r = read(fd, p, mfd_def_size);
+	if (r < 0) {
+		printf("read() failed: %m\n");
+		abort();
+	} else if (!r) {
+		printf("unexpected EOF on read()\n");
+		abort();
+	}
+
+	was_sealed = mfd_assert_get_seals(mfd) & F_SEAL_WRITE;
+
+	/* Wait for sealing-thread to finish and verify that it
+	 * successfully sealed the file after the second try. */
+	join_sealing_thread(pid);
+	mfd_assert_has_seals(mfd, F_SEAL_WRITE);
+
+	/* *IF* the memfd-object was sealed at the time our read() returned,
+	 * then the kernel did a page-replacement or canceled the read() (or
+	 * whatever magic it did..). In that case, the memfd object is still
+	 * all zero.
+	 * In case the memfd-object was *not* sealed, the read() was successful
+	 * and the memfd object must *not* be all zero.
+	 * Note that in real scenarios, there might be a mixture of both, but
+	 * in this test-cases, we have explicit 200ms delays which should be
+	 * enough to avoid any in-flight writes. */
+
+	p = mfd_assert_mmap_private(mfd);
+	if (was_sealed && memcmp(p, zero, mfd_def_size)) {
+		printf("memfd sealed during read() but data not discarded\n");
+		abort();
+	} else if (!was_sealed && !memcmp(p, zero, mfd_def_size)) {
+		printf("memfd sealed after read() but data discarded\n");
+		abort();
+	}
+
+	close(mfd);
+	close(fd);
+
+	printf("fuse: DONE\n");
+	free(zero);
+
+	return 0;
+}
diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c
new file mode 100644
index 000000000..cdab3a837
--- /dev/null
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -0,0 +1,1764 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#define __EXPORTED_HEADERS__
+
+#include <errno.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <linux/falloc.h>
+#include <fcntl.h>
+#include <linux/memfd.h>
+#include <sched.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/wait.h>
+#include <sys/types.h>
+#include <sys/ipc.h>
+#include <sys/sem.h>
+#include <unistd.h>
+#include <ctype.h>
+
+#include "common.h"
+
+#define MEMFD_STR	"memfd:"
+#define MEMFD_HUGE_STR	"memfd-hugetlb:"
+#define SHARED_FT_STR	"(shared file-table)"
+
+#define MFD_DEF_SIZE 8192
+#define STACK_SIZE 65536
+
+#define F_SEAL_EXEC	0x0020
+
+#define F_WX_SEALS (F_SEAL_SHRINK | \
+		    F_SEAL_GROW | \
+		    F_SEAL_WRITE | \
+		    F_SEAL_FUTURE_WRITE | \
+		    F_SEAL_EXEC)
+
+#define MFD_NOEXEC_SEAL	0x0008U
+union semun {
+	int val;
+	struct semid_ds *buf;
+	unsigned short int *array;
+	struct seminfo *__buf;
+};
+
+/*
+ * we use semaphores on nested wait tasks due the use of CLONE_NEWPID: the
+ * child will be PID 1 and can't send SIGSTOP to themselves due special
+ * treatment of the init task, so the SIGSTOP/SIGCONT synchronization
+ * approach can't be used here.
+ */
+#define SEM_KEY 0xdeadbeef
+
+/*
+ * Default is not to test hugetlbfs
+ */
+static size_t mfd_def_size = MFD_DEF_SIZE;
+static const char *memfd_str = MEMFD_STR;
+
+static ssize_t fd2name(int fd, char *buf, size_t bufsize)
+{
+	char buf1[PATH_MAX];
+	int size;
+	ssize_t nbytes;
+
+	size = snprintf(buf1, PATH_MAX, "/proc/self/fd/%d", fd);
+	if (size < 0) {
+		printf("snprintf(%d) failed on %m\n", fd);
+		abort();
+	}
+
+	/*
+	 * reserver one byte for string termination.
+	 */
+	nbytes = readlink(buf1, buf, bufsize-1);
+	if (nbytes == -1) {
+		printf("readlink(%s) failed %m\n", buf1);
+		abort();
+	}
+	buf[nbytes] = '\0';
+	return nbytes;
+}
+
+static int mfd_assert_new(const char *name, loff_t sz, unsigned int flags)
+{
+	int r, fd;
+
+	fd = sys_memfd_create(name, flags);
+	if (fd < 0) {
+		printf("memfd_create(\"%s\", %u) failed: %m\n",
+		       name, flags);
+		abort();
+	}
+
+	r = ftruncate(fd, sz);
+	if (r < 0) {
+		printf("ftruncate(%llu) failed: %m\n", (unsigned long long)sz);
+		abort();
+	}
+
+	return fd;
+}
+
+static void sysctl_assert_write(const char *val)
+{
+	int fd = open("/proc/sys/vm/memfd_noexec", O_WRONLY | O_CLOEXEC);
+
+	if (fd < 0) {
+		printf("open sysctl failed: %m\n");
+		abort();
+	}
+
+	if (write(fd, val, strlen(val)) < 0) {
+		printf("write sysctl %s failed: %m\n", val);
+		abort();
+	}
+}
+
+static void sysctl_fail_write(const char *val)
+{
+	int fd = open("/proc/sys/vm/memfd_noexec", O_WRONLY | O_CLOEXEC);
+
+	if (fd < 0) {
+		printf("open sysctl failed: %m\n");
+		abort();
+	}
+
+	if (write(fd, val, strlen(val)) >= 0) {
+		printf("write sysctl %s succeeded, but failure expected\n",
+				val);
+		abort();
+	}
+}
+
+static void sysctl_assert_equal(const char *val)
+{
+	char *p, buf[128] = {};
+	int fd = open("/proc/sys/vm/memfd_noexec", O_RDONLY | O_CLOEXEC);
+
+	if (fd < 0) {
+		printf("open sysctl failed: %m\n");
+		abort();
+	}
+
+	if (read(fd, buf, sizeof(buf)) < 0) {
+		printf("read sysctl failed: %m\n");
+		abort();
+	}
+
+	/* Strip trailing whitespace. */
+	p = buf;
+	while (!isspace(*p))
+		p++;
+	*p = '\0';
+
+	if (strcmp(buf, val) != 0) {
+		printf("unexpected sysctl value: expected %s, got %s\n", val, buf);
+		abort();
+	}
+}
+
+static int mfd_assert_reopen_fd(int fd_in)
+{
+	int fd;
+	char path[100];
+
+	sprintf(path, "/proc/self/fd/%d", fd_in);
+
+	fd = open(path, O_RDWR);
+	if (fd < 0) {
+		printf("re-open of existing fd %d failed\n", fd_in);
+		abort();
+	}
+
+	return fd;
+}
+
+static void mfd_fail_new(const char *name, unsigned int flags)
+{
+	int r;
+
+	r = sys_memfd_create(name, flags);
+	if (r >= 0) {
+		printf("memfd_create(\"%s\", %u) succeeded, but failure expected\n",
+		       name ? name : "NULL", flags);
+		close(r);
+		abort();
+	}
+}
+
+static unsigned int mfd_assert_get_seals(int fd)
+{
+	int r;
+
+	r = fcntl(fd, F_GET_SEALS);
+	if (r < 0) {
+		printf("GET_SEALS(%d) failed: %m\n", fd);
+		abort();
+	}
+
+	return (unsigned int)r;
+}
+
+static void mfd_assert_has_seals(int fd, unsigned int seals)
+{
+	char buf[PATH_MAX];
+	unsigned int s;
+	fd2name(fd, buf, PATH_MAX);
+
+	s = mfd_assert_get_seals(fd);
+	if (s != seals) {
+		printf("%u != %u = GET_SEALS(%s)\n", seals, s, buf);
+		abort();
+	}
+}
+
+static void mfd_assert_add_seals(int fd, unsigned int seals)
+{
+	int r;
+	unsigned int s;
+
+	s = mfd_assert_get_seals(fd);
+	r = fcntl(fd, F_ADD_SEALS, seals);
+	if (r < 0) {
+		printf("ADD_SEALS(%d, %u -> %u) failed: %m\n", fd, s, seals);
+		abort();
+	}
+}
+
+static void mfd_fail_add_seals(int fd, unsigned int seals)
+{
+	int r;
+	unsigned int s;
+
+	r = fcntl(fd, F_GET_SEALS);
+	if (r < 0)
+		s = 0;
+	else
+		s = (unsigned int)r;
+
+	r = fcntl(fd, F_ADD_SEALS, seals);
+	if (r >= 0) {
+		printf("ADD_SEALS(%d, %u -> %u) didn't fail as expected\n",
+				fd, s, seals);
+		abort();
+	}
+}
+
+static void mfd_assert_size(int fd, size_t size)
+{
+	struct stat st;
+	int r;
+
+	r = fstat(fd, &st);
+	if (r < 0) {
+		printf("fstat(%d) failed: %m\n", fd);
+		abort();
+	} else if (st.st_size != size) {
+		printf("wrong file size %lld, but expected %lld\n",
+		       (long long)st.st_size, (long long)size);
+		abort();
+	}
+}
+
+static int mfd_assert_dup(int fd)
+{
+	int r;
+
+	r = dup(fd);
+	if (r < 0) {
+		printf("dup(%d) failed: %m\n", fd);
+		abort();
+	}
+
+	return r;
+}
+
+static void *mfd_assert_mmap_shared(int fd)
+{
+	void *p;
+
+	p = mmap(NULL,
+		 mfd_def_size,
+		 PROT_READ | PROT_WRITE,
+		 MAP_SHARED,
+		 fd,
+		 0);
+	if (p == MAP_FAILED) {
+		printf("mmap() failed: %m\n");
+		abort();
+	}
+
+	return p;
+}
+
+static void *mfd_assert_mmap_read_shared(int fd)
+{
+	void *p;
+
+	p = mmap(NULL,
+		 mfd_def_size,
+		 PROT_READ,
+		 MAP_SHARED,
+		 fd,
+		 0);
+	if (p == MAP_FAILED) {
+		printf("mmap() failed: %m\n");
+		abort();
+	}
+
+	return p;
+}
+
+static void *mfd_assert_mmap_private(int fd)
+{
+	void *p;
+
+	p = mmap(NULL,
+		 mfd_def_size,
+		 PROT_READ,
+		 MAP_PRIVATE,
+		 fd,
+		 0);
+	if (p == MAP_FAILED) {
+		printf("mmap() failed: %m\n");
+		abort();
+	}
+
+	return p;
+}
+
+static int mfd_assert_open(int fd, int flags, mode_t mode)
+{
+	char buf[512];
+	int r;
+
+	sprintf(buf, "/proc/self/fd/%d", fd);
+	r = open(buf, flags, mode);
+	if (r < 0) {
+		printf("open(%s) failed: %m\n", buf);
+		abort();
+	}
+
+	return r;
+}
+
+static void mfd_fail_open(int fd, int flags, mode_t mode)
+{
+	char buf[512];
+	int r;
+
+	sprintf(buf, "/proc/self/fd/%d", fd);
+	r = open(buf, flags, mode);
+	if (r >= 0) {
+		printf("open(%s) didn't fail as expected\n", buf);
+		abort();
+	}
+}
+
+static void mfd_assert_read(int fd)
+{
+	char buf[16];
+	void *p;
+	ssize_t l;
+
+	l = read(fd, buf, sizeof(buf));
+	if (l != sizeof(buf)) {
+		printf("read() failed: %m\n");
+		abort();
+	}
+
+	/* verify PROT_READ *is* allowed */
+	p = mmap(NULL,
+		 mfd_def_size,
+		 PROT_READ,
+		 MAP_PRIVATE,
+		 fd,
+		 0);
+	if (p == MAP_FAILED) {
+		printf("mmap() failed: %m\n");
+		abort();
+	}
+	munmap(p, mfd_def_size);
+
+	/* verify MAP_PRIVATE is *always* allowed (even writable) */
+	p = mmap(NULL,
+		 mfd_def_size,
+		 PROT_READ | PROT_WRITE,
+		 MAP_PRIVATE,
+		 fd,
+		 0);
+	if (p == MAP_FAILED) {
+		printf("mmap() failed: %m\n");
+		abort();
+	}
+	munmap(p, mfd_def_size);
+}
+
+/* Test that PROT_READ + MAP_SHARED mappings work. */
+static void mfd_assert_read_shared(int fd)
+{
+	void *p;
+
+	/* verify PROT_READ and MAP_SHARED *is* allowed */
+	p = mmap(NULL,
+		 mfd_def_size,
+		 PROT_READ,
+		 MAP_SHARED,
+		 fd,
+		 0);
+	if (p == MAP_FAILED) {
+		printf("mmap() failed: %m\n");
+		abort();
+	}
+	munmap(p, mfd_def_size);
+}
+
+static void mfd_assert_fork_private_write(int fd)
+{
+	int *p;
+	pid_t pid;
+
+	p = mmap(NULL,
+		 mfd_def_size,
+		 PROT_READ | PROT_WRITE,
+		 MAP_PRIVATE,
+		 fd,
+		 0);
+	if (p == MAP_FAILED) {
+		printf("mmap() failed: %m\n");
+		abort();
+	}
+
+	p[0] = 22;
+
+	pid = fork();
+	if (pid == 0) {
+		p[0] = 33;
+		exit(0);
+	} else {
+		waitpid(pid, NULL, 0);
+
+		if (p[0] != 22) {
+			printf("MAP_PRIVATE copy-on-write failed: %m\n");
+			abort();
+		}
+	}
+
+	munmap(p, mfd_def_size);
+}
+
+static void mfd_assert_write(int fd)
+{
+	ssize_t l;
+	void *p;
+	int r;
+
+	/*
+	 * huegtlbfs does not support write, but we want to
+	 * verify everything else here.
+	 */
+	if (!hugetlbfs_test) {
+		/* verify write() succeeds */
+		l = write(fd, "\0\0\0\0", 4);
+		if (l != 4) {
+			printf("write() failed: %m\n");
+			abort();
+		}
+	}
+
+	/* verify PROT_READ | PROT_WRITE is allowed */
+	p = mmap(NULL,
+		 mfd_def_size,
+		 PROT_READ | PROT_WRITE,
+		 MAP_SHARED,
+		 fd,
+		 0);
+	if (p == MAP_FAILED) {
+		printf("mmap() failed: %m\n");
+		abort();
+	}
+	*(char *)p = 0;
+	munmap(p, mfd_def_size);
+
+	/* verify PROT_WRITE is allowed */
+	p = mmap(NULL,
+		 mfd_def_size,
+		 PROT_WRITE,
+		 MAP_SHARED,
+		 fd,
+		 0);
+	if (p == MAP_FAILED) {
+		printf("mmap() failed: %m\n");
+		abort();
+	}
+	*(char *)p = 0;
+	munmap(p, mfd_def_size);
+
+	/* verify PROT_READ with MAP_SHARED is allowed and a following
+	 * mprotect(PROT_WRITE) allows writing */
+	p = mmap(NULL,
+		 mfd_def_size,
+		 PROT_READ,
+		 MAP_SHARED,
+		 fd,
+		 0);
+	if (p == MAP_FAILED) {
+		printf("mmap() failed: %m\n");
+		abort();
+	}
+
+	r = mprotect(p, mfd_def_size, PROT_READ | PROT_WRITE);
+	if (r < 0) {
+		printf("mprotect() failed: %m\n");
+		abort();
+	}
+
+	*(char *)p = 0;
+	munmap(p, mfd_def_size);
+
+	/* verify PUNCH_HOLE works */
+	r = fallocate(fd,
+		      FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+		      0,
+		      mfd_def_size);
+	if (r < 0) {
+		printf("fallocate(PUNCH_HOLE) failed: %m\n");
+		abort();
+	}
+}
+
+static void mfd_fail_write(int fd)
+{
+	ssize_t l;
+	void *p;
+	int r;
+
+	/* verify write() fails */
+	l = write(fd, "data", 4);
+	if (l != -EPERM) {
+		printf("expected EPERM on write(), but got %d: %m\n", (int)l);
+		abort();
+	}
+
+	/* verify PROT_READ | PROT_WRITE is not allowed */
+	p = mmap(NULL,
+		 mfd_def_size,
+		 PROT_READ | PROT_WRITE,
+		 MAP_SHARED,
+		 fd,
+		 0);
+	if (p != MAP_FAILED) {
+		printf("mmap() didn't fail as expected\n");
+		abort();
+	}
+
+	/* verify PROT_WRITE is not allowed */
+	p = mmap(NULL,
+		 mfd_def_size,
+		 PROT_WRITE,
+		 MAP_SHARED,
+		 fd,
+		 0);
+	if (p != MAP_FAILED) {
+		printf("mmap() didn't fail as expected\n");
+		abort();
+	}
+
+	/* Verify PROT_READ with MAP_SHARED with a following mprotect is not
+	 * allowed. Note that for r/w the kernel already prevents the mmap. */
+	p = mmap(NULL,
+		 mfd_def_size,
+		 PROT_READ,
+		 MAP_SHARED,
+		 fd,
+		 0);
+	if (p != MAP_FAILED) {
+		r = mprotect(p, mfd_def_size, PROT_READ | PROT_WRITE);
+		if (r >= 0) {
+			printf("mmap()+mprotect() didn't fail as expected\n");
+			abort();
+		}
+		munmap(p, mfd_def_size);
+	}
+
+	/* verify PUNCH_HOLE fails */
+	r = fallocate(fd,
+		      FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+		      0,
+		      mfd_def_size);
+	if (r >= 0) {
+		printf("fallocate(PUNCH_HOLE) didn't fail as expected\n");
+		abort();
+	}
+}
+
+static void mfd_assert_shrink(int fd)
+{
+	int r, fd2;
+
+	r = ftruncate(fd, mfd_def_size / 2);
+	if (r < 0) {
+		printf("ftruncate(SHRINK) failed: %m\n");
+		abort();
+	}
+
+	mfd_assert_size(fd, mfd_def_size / 2);
+
+	fd2 = mfd_assert_open(fd,
+			      O_RDWR | O_CREAT | O_TRUNC,
+			      S_IRUSR | S_IWUSR);
+	close(fd2);
+
+	mfd_assert_size(fd, 0);
+}
+
+static void mfd_fail_shrink(int fd)
+{
+	int r;
+
+	r = ftruncate(fd, mfd_def_size / 2);
+	if (r >= 0) {
+		printf("ftruncate(SHRINK) didn't fail as expected\n");
+		abort();
+	}
+
+	mfd_fail_open(fd,
+		      O_RDWR | O_CREAT | O_TRUNC,
+		      S_IRUSR | S_IWUSR);
+}
+
+static void mfd_assert_grow(int fd)
+{
+	int r;
+
+	r = ftruncate(fd, mfd_def_size * 2);
+	if (r < 0) {
+		printf("ftruncate(GROW) failed: %m\n");
+		abort();
+	}
+
+	mfd_assert_size(fd, mfd_def_size * 2);
+
+	r = fallocate(fd,
+		      0,
+		      0,
+		      mfd_def_size * 4);
+	if (r < 0) {
+		printf("fallocate(ALLOC) failed: %m\n");
+		abort();
+	}
+
+	mfd_assert_size(fd, mfd_def_size * 4);
+}
+
+static void mfd_fail_grow(int fd)
+{
+	int r;
+
+	r = ftruncate(fd, mfd_def_size * 2);
+	if (r >= 0) {
+		printf("ftruncate(GROW) didn't fail as expected\n");
+		abort();
+	}
+
+	r = fallocate(fd,
+		      0,
+		      0,
+		      mfd_def_size * 4);
+	if (r >= 0) {
+		printf("fallocate(ALLOC) didn't fail as expected\n");
+		abort();
+	}
+}
+
+static void mfd_assert_grow_write(int fd)
+{
+	static char *buf;
+	ssize_t l;
+
+	/* hugetlbfs does not support write */
+	if (hugetlbfs_test)
+		return;
+
+	buf = calloc(1, mfd_def_size * 8);
+	if (!buf) {
+		printf("calloc(1, %zu) failed: %m\n", mfd_def_size * 8);
+		abort();
+	}
+
+	l = pwrite(fd, buf, mfd_def_size * 8, 0);
+	if (l != (mfd_def_size * 8)) {
+		printf("pwrite() failed: %m\n");
+		abort();
+	}
+
+	mfd_assert_size(fd, mfd_def_size * 8);
+}
+
+static void mfd_fail_grow_write(int fd)
+{
+	static char *buf;
+	ssize_t l;
+
+	/* hugetlbfs does not support write */
+	if (hugetlbfs_test)
+		return;
+
+	buf = malloc(mfd_def_size * 8);
+	if (!buf) {
+		printf("malloc(%zu) failed: %m\n", mfd_def_size * 8);
+		abort();
+	}
+
+	l = pwrite(fd, buf, mfd_def_size * 8, 0);
+	if (l == (mfd_def_size * 8)) {
+		printf("pwrite() didn't fail as expected\n");
+		abort();
+	}
+}
+
+static void mfd_assert_mode(int fd, int mode)
+{
+	struct stat st;
+	char buf[PATH_MAX];
+
+	fd2name(fd, buf, PATH_MAX);
+
+	if (fstat(fd, &st) < 0) {
+		printf("fstat(%s) failed: %m\n", buf);
+		abort();
+	}
+
+	if ((st.st_mode & 07777) != mode) {
+		printf("fstat(%s) wrong file mode 0%04o, but expected 0%04o\n",
+		       buf, (int)st.st_mode & 07777, mode);
+		abort();
+	}
+}
+
+static void mfd_assert_chmod(int fd, int mode)
+{
+	char buf[PATH_MAX];
+
+	fd2name(fd, buf, PATH_MAX);
+
+	if (fchmod(fd, mode) < 0) {
+		printf("fchmod(%s, 0%04o) failed: %m\n", buf, mode);
+		abort();
+	}
+
+	mfd_assert_mode(fd, mode);
+}
+
+static void mfd_fail_chmod(int fd, int mode)
+{
+	struct stat st;
+	char buf[PATH_MAX];
+
+	fd2name(fd, buf, PATH_MAX);
+
+	if (fstat(fd, &st) < 0) {
+		printf("fstat(%s) failed: %m\n", buf);
+		abort();
+	}
+
+	if (fchmod(fd, mode) == 0) {
+		printf("fchmod(%s, 0%04o) didn't fail as expected\n",
+		       buf, mode);
+		abort();
+	}
+
+	/* verify that file mode bits did not change */
+	mfd_assert_mode(fd, st.st_mode & 07777);
+}
+
+static int idle_thread_fn(void *arg)
+{
+	sigset_t set;
+	int sig;
+
+	/* dummy waiter; SIGTERM terminates us anyway */
+	sigemptyset(&set);
+	sigaddset(&set, SIGTERM);
+	sigwait(&set, &sig);
+
+	return 0;
+}
+
+static pid_t spawn_thread(unsigned int flags, int (*fn)(void *), void *arg)
+{
+	uint8_t *stack;
+	pid_t pid;
+
+	stack = malloc(STACK_SIZE);
+	if (!stack) {
+		printf("malloc(STACK_SIZE) failed: %m\n");
+		abort();
+	}
+
+	pid = clone(fn, stack + STACK_SIZE, SIGCHLD | flags, arg);
+	if (pid < 0) {
+		printf("clone() failed: %m\n");
+		abort();
+	}
+
+	return pid;
+}
+
+static void join_thread(pid_t pid)
+{
+	int wstatus;
+
+	if (waitpid(pid, &wstatus, 0) < 0) {
+		printf("newpid thread: waitpid() failed: %m\n");
+		abort();
+	}
+
+	if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) != 0) {
+		printf("newpid thread: exited with non-zero error code %d\n",
+		       WEXITSTATUS(wstatus));
+		abort();
+	}
+
+	if (WIFSIGNALED(wstatus)) {
+		printf("newpid thread: killed by signal %d\n",
+		       WTERMSIG(wstatus));
+		abort();
+	}
+}
+
+static pid_t spawn_idle_thread(unsigned int flags)
+{
+	return spawn_thread(flags, idle_thread_fn, NULL);
+}
+
+static void join_idle_thread(pid_t pid)
+{
+	kill(pid, SIGTERM);
+	waitpid(pid, NULL, 0);
+}
+
+/*
+ * Test memfd_create() syscall
+ * Verify syscall-argument validation, including name checks, flag validation
+ * and more.
+ */
+static void test_create(void)
+{
+	char buf[2048];
+	int fd;
+
+	printf("%s CREATE\n", memfd_str);
+
+	/* test NULL name */
+	mfd_fail_new(NULL, 0);
+
+	/* test over-long name (not zero-terminated) */
+	memset(buf, 0xff, sizeof(buf));
+	mfd_fail_new(buf, 0);
+
+	/* test over-long zero-terminated name */
+	memset(buf, 0xff, sizeof(buf));
+	buf[sizeof(buf) - 1] = 0;
+	mfd_fail_new(buf, 0);
+
+	/* verify "" is a valid name */
+	fd = mfd_assert_new("", 0, 0);
+	close(fd);
+
+	/* verify invalid O_* open flags */
+	mfd_fail_new("", 0x0100);
+	mfd_fail_new("", ~MFD_CLOEXEC);
+	mfd_fail_new("", ~MFD_ALLOW_SEALING);
+	mfd_fail_new("", ~0);
+	mfd_fail_new("", 0x80000000U);
+
+	/* verify EXEC and NOEXEC_SEAL can't both be set */
+	mfd_fail_new("", MFD_EXEC | MFD_NOEXEC_SEAL);
+
+	/* verify MFD_CLOEXEC is allowed */
+	fd = mfd_assert_new("", 0, MFD_CLOEXEC);
+	close(fd);
+
+	/* verify MFD_ALLOW_SEALING is allowed */
+	fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING);
+	close(fd);
+
+	/* verify MFD_ALLOW_SEALING | MFD_CLOEXEC is allowed */
+	fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING | MFD_CLOEXEC);
+	close(fd);
+}
+
+/*
+ * Test basic sealing
+ * A very basic sealing test to see whether setting/retrieving seals works.
+ */
+static void test_basic(void)
+{
+	int fd;
+
+	printf("%s BASIC\n", memfd_str);
+
+	fd = mfd_assert_new("kern_memfd_basic",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
+
+	/* add basic seals */
+	mfd_assert_has_seals(fd, 0);
+	mfd_assert_add_seals(fd, F_SEAL_SHRINK |
+				 F_SEAL_WRITE);
+	mfd_assert_has_seals(fd, F_SEAL_SHRINK |
+				 F_SEAL_WRITE);
+
+	/* add them again */
+	mfd_assert_add_seals(fd, F_SEAL_SHRINK |
+				 F_SEAL_WRITE);
+	mfd_assert_has_seals(fd, F_SEAL_SHRINK |
+				 F_SEAL_WRITE);
+
+	/* add more seals and seal against sealing */
+	mfd_assert_add_seals(fd, F_SEAL_GROW | F_SEAL_SEAL);
+	mfd_assert_has_seals(fd, F_SEAL_SHRINK |
+				 F_SEAL_GROW |
+				 F_SEAL_WRITE |
+				 F_SEAL_SEAL);
+
+	/* verify that sealing no longer works */
+	mfd_fail_add_seals(fd, F_SEAL_GROW);
+	mfd_fail_add_seals(fd, 0);
+
+	close(fd);
+
+	/* verify sealing does not work without MFD_ALLOW_SEALING */
+	fd = mfd_assert_new("kern_memfd_basic",
+			    mfd_def_size,
+			    MFD_CLOEXEC);
+	mfd_assert_has_seals(fd, F_SEAL_SEAL);
+	mfd_fail_add_seals(fd, F_SEAL_SHRINK |
+			       F_SEAL_GROW |
+			       F_SEAL_WRITE);
+	mfd_assert_has_seals(fd, F_SEAL_SEAL);
+	close(fd);
+}
+
+/*
+ * Test SEAL_WRITE
+ * Test whether SEAL_WRITE actually prevents modifications.
+ */
+static void test_seal_write(void)
+{
+	int fd;
+
+	printf("%s SEAL-WRITE\n", memfd_str);
+
+	fd = mfd_assert_new("kern_memfd_seal_write",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
+	mfd_assert_has_seals(fd, 0);
+	mfd_assert_add_seals(fd, F_SEAL_WRITE);
+	mfd_assert_has_seals(fd, F_SEAL_WRITE);
+
+	mfd_assert_read(fd);
+	mfd_fail_write(fd);
+	mfd_assert_shrink(fd);
+	mfd_assert_grow(fd);
+	mfd_fail_grow_write(fd);
+
+	close(fd);
+}
+
+/*
+ * Test SEAL_FUTURE_WRITE
+ * Test whether SEAL_FUTURE_WRITE actually prevents modifications.
+ */
+static void test_seal_future_write(void)
+{
+	int fd, fd2;
+	void *p;
+
+	printf("%s SEAL-FUTURE-WRITE\n", memfd_str);
+
+	fd = mfd_assert_new("kern_memfd_seal_future_write",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
+
+	p = mfd_assert_mmap_shared(fd);
+
+	mfd_assert_has_seals(fd, 0);
+
+	mfd_assert_add_seals(fd, F_SEAL_FUTURE_WRITE);
+	mfd_assert_has_seals(fd, F_SEAL_FUTURE_WRITE);
+
+	/* read should pass, writes should fail */
+	mfd_assert_read(fd);
+	mfd_assert_read_shared(fd);
+	mfd_fail_write(fd);
+
+	fd2 = mfd_assert_reopen_fd(fd);
+	/* read should pass, writes should still fail */
+	mfd_assert_read(fd2);
+	mfd_assert_read_shared(fd2);
+	mfd_fail_write(fd2);
+
+	mfd_assert_fork_private_write(fd);
+
+	munmap(p, mfd_def_size);
+	close(fd2);
+	close(fd);
+}
+
+static void test_seal_write_map_read_shared(void)
+{
+	int fd;
+	void *p;
+
+	printf("%s SEAL-WRITE-MAP-READ\n", memfd_str);
+
+	fd = mfd_assert_new("kern_memfd_seal_write_map_read",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
+
+	mfd_assert_add_seals(fd, F_SEAL_WRITE);
+	mfd_assert_has_seals(fd, F_SEAL_WRITE);
+
+	p = mfd_assert_mmap_read_shared(fd);
+
+	mfd_assert_read(fd);
+	mfd_assert_read_shared(fd);
+	mfd_fail_write(fd);
+
+	munmap(p, mfd_def_size);
+	close(fd);
+}
+
+/*
+ * Test SEAL_SHRINK
+ * Test whether SEAL_SHRINK actually prevents shrinking
+ */
+static void test_seal_shrink(void)
+{
+	int fd;
+
+	printf("%s SEAL-SHRINK\n", memfd_str);
+
+	fd = mfd_assert_new("kern_memfd_seal_shrink",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
+	mfd_assert_has_seals(fd, 0);
+	mfd_assert_add_seals(fd, F_SEAL_SHRINK);
+	mfd_assert_has_seals(fd, F_SEAL_SHRINK);
+
+	mfd_assert_read(fd);
+	mfd_assert_write(fd);
+	mfd_fail_shrink(fd);
+	mfd_assert_grow(fd);
+	mfd_assert_grow_write(fd);
+
+	close(fd);
+}
+
+/*
+ * Test SEAL_GROW
+ * Test whether SEAL_GROW actually prevents growing
+ */
+static void test_seal_grow(void)
+{
+	int fd;
+
+	printf("%s SEAL-GROW\n", memfd_str);
+
+	fd = mfd_assert_new("kern_memfd_seal_grow",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
+	mfd_assert_has_seals(fd, 0);
+	mfd_assert_add_seals(fd, F_SEAL_GROW);
+	mfd_assert_has_seals(fd, F_SEAL_GROW);
+
+	mfd_assert_read(fd);
+	mfd_assert_write(fd);
+	mfd_assert_shrink(fd);
+	mfd_fail_grow(fd);
+	mfd_fail_grow_write(fd);
+
+	close(fd);
+}
+
+/*
+ * Test SEAL_SHRINK | SEAL_GROW
+ * Test whether SEAL_SHRINK | SEAL_GROW actually prevents resizing
+ */
+static void test_seal_resize(void)
+{
+	int fd;
+
+	printf("%s SEAL-RESIZE\n", memfd_str);
+
+	fd = mfd_assert_new("kern_memfd_seal_resize",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
+	mfd_assert_has_seals(fd, 0);
+	mfd_assert_add_seals(fd, F_SEAL_SHRINK | F_SEAL_GROW);
+	mfd_assert_has_seals(fd, F_SEAL_SHRINK | F_SEAL_GROW);
+
+	mfd_assert_read(fd);
+	mfd_assert_write(fd);
+	mfd_fail_shrink(fd);
+	mfd_fail_grow(fd);
+	mfd_fail_grow_write(fd);
+
+	close(fd);
+}
+
+/*
+ * Test SEAL_EXEC
+ * Test fd is created with exec and allow sealing.
+ * chmod() cannot change x bits after sealing.
+ */
+static void test_exec_seal(void)
+{
+	int fd;
+
+	printf("%s SEAL-EXEC\n", memfd_str);
+
+	printf("%s	Apply SEAL_EXEC\n", memfd_str);
+	fd = mfd_assert_new("kern_memfd_seal_exec",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_EXEC);
+
+	mfd_assert_mode(fd, 0777);
+	mfd_assert_chmod(fd, 0644);
+
+	mfd_assert_has_seals(fd, 0);
+	mfd_assert_add_seals(fd, F_SEAL_EXEC);
+	mfd_assert_has_seals(fd, F_SEAL_EXEC);
+
+	mfd_assert_chmod(fd, 0600);
+	mfd_fail_chmod(fd, 0777);
+	mfd_fail_chmod(fd, 0670);
+	mfd_fail_chmod(fd, 0605);
+	mfd_fail_chmod(fd, 0700);
+	mfd_fail_chmod(fd, 0100);
+	mfd_assert_chmod(fd, 0666);
+	mfd_assert_write(fd);
+	close(fd);
+
+	printf("%s	Apply ALL_SEALS\n", memfd_str);
+	fd = mfd_assert_new("kern_memfd_seal_exec",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_EXEC);
+
+	mfd_assert_mode(fd, 0777);
+	mfd_assert_chmod(fd, 0700);
+
+	mfd_assert_has_seals(fd, 0);
+	mfd_assert_add_seals(fd, F_SEAL_EXEC);
+	mfd_assert_has_seals(fd, F_WX_SEALS);
+
+	mfd_fail_chmod(fd, 0711);
+	mfd_fail_chmod(fd, 0600);
+	mfd_fail_write(fd);
+	close(fd);
+}
+
+/*
+ * Test EXEC_NO_SEAL
+ * Test fd is created with exec and not allow sealing.
+ */
+static void test_exec_no_seal(void)
+{
+	int fd;
+
+	printf("%s EXEC_NO_SEAL\n", memfd_str);
+
+	/* Create with EXEC but without ALLOW_SEALING */
+	fd = mfd_assert_new("kern_memfd_exec_no_sealing",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_EXEC);
+	mfd_assert_mode(fd, 0777);
+	mfd_assert_has_seals(fd, F_SEAL_SEAL);
+	mfd_assert_chmod(fd, 0666);
+	close(fd);
+}
+
+/*
+ * Test memfd_create with MFD_NOEXEC flag
+ */
+static void test_noexec_seal(void)
+{
+	int fd;
+
+	printf("%s NOEXEC_SEAL\n", memfd_str);
+
+	/* Create with NOEXEC and ALLOW_SEALING */
+	fd = mfd_assert_new("kern_memfd_noexec",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_NOEXEC_SEAL);
+	mfd_assert_mode(fd, 0666);
+	mfd_assert_has_seals(fd, F_SEAL_EXEC);
+	mfd_fail_chmod(fd, 0777);
+	close(fd);
+
+	/* Create with NOEXEC but without ALLOW_SEALING */
+	fd = mfd_assert_new("kern_memfd_noexec",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_NOEXEC_SEAL);
+	mfd_assert_mode(fd, 0666);
+	mfd_assert_has_seals(fd, F_SEAL_EXEC);
+	mfd_fail_chmod(fd, 0777);
+	close(fd);
+}
+
+static void test_sysctl_sysctl0(void)
+{
+	int fd;
+
+	sysctl_assert_equal("0");
+
+	fd = mfd_assert_new("kern_memfd_sysctl_0_dfl",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
+	mfd_assert_mode(fd, 0777);
+	mfd_assert_has_seals(fd, 0);
+	mfd_assert_chmod(fd, 0644);
+	close(fd);
+}
+
+static void test_sysctl_set_sysctl0(void)
+{
+	sysctl_assert_write("0");
+	test_sysctl_sysctl0();
+}
+
+static void test_sysctl_sysctl1(void)
+{
+	int fd;
+
+	sysctl_assert_equal("1");
+
+	fd = mfd_assert_new("kern_memfd_sysctl_1_dfl",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
+	mfd_assert_mode(fd, 0666);
+	mfd_assert_has_seals(fd, F_SEAL_EXEC);
+	mfd_fail_chmod(fd, 0777);
+	close(fd);
+
+	fd = mfd_assert_new("kern_memfd_sysctl_1_exec",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_EXEC | MFD_ALLOW_SEALING);
+	mfd_assert_mode(fd, 0777);
+	mfd_assert_has_seals(fd, 0);
+	mfd_assert_chmod(fd, 0644);
+	close(fd);
+
+	fd = mfd_assert_new("kern_memfd_sysctl_1_noexec",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_NOEXEC_SEAL | MFD_ALLOW_SEALING);
+	mfd_assert_mode(fd, 0666);
+	mfd_assert_has_seals(fd, F_SEAL_EXEC);
+	mfd_fail_chmod(fd, 0777);
+	close(fd);
+}
+
+static void test_sysctl_set_sysctl1(void)
+{
+	sysctl_assert_write("1");
+	test_sysctl_sysctl1();
+}
+
+static void test_sysctl_sysctl2(void)
+{
+	int fd;
+
+	sysctl_assert_equal("2");
+
+	fd = mfd_assert_new("kern_memfd_sysctl_2_dfl",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
+	mfd_assert_mode(fd, 0666);
+	mfd_assert_has_seals(fd, F_SEAL_EXEC);
+	mfd_fail_chmod(fd, 0777);
+	close(fd);
+
+	mfd_fail_new("kern_memfd_sysctl_2_exec",
+		     MFD_CLOEXEC | MFD_EXEC | MFD_ALLOW_SEALING);
+
+	fd = mfd_assert_new("kern_memfd_sysctl_2_noexec",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_NOEXEC_SEAL | MFD_ALLOW_SEALING);
+	mfd_assert_mode(fd, 0666);
+	mfd_assert_has_seals(fd, F_SEAL_EXEC);
+	mfd_fail_chmod(fd, 0777);
+	close(fd);
+}
+
+static void test_sysctl_set_sysctl2(void)
+{
+	sysctl_assert_write("2");
+	test_sysctl_sysctl2();
+}
+
+static int sysctl_simple_child(void *arg)
+{
+	printf("%s sysctl 0\n", memfd_str);
+	test_sysctl_set_sysctl0();
+
+	printf("%s sysctl 1\n", memfd_str);
+	test_sysctl_set_sysctl1();
+
+	printf("%s sysctl 0\n", memfd_str);
+	test_sysctl_set_sysctl0();
+
+	printf("%s sysctl 2\n", memfd_str);
+	test_sysctl_set_sysctl2();
+
+	printf("%s sysctl 1\n", memfd_str);
+	test_sysctl_set_sysctl1();
+
+	printf("%s sysctl 0\n", memfd_str);
+	test_sysctl_set_sysctl0();
+
+	return 0;
+}
+
+/*
+ * Test sysctl
+ * A very basic test to make sure the core sysctl semantics work.
+ */
+static void test_sysctl_simple(void)
+{
+	int pid = spawn_thread(CLONE_NEWPID, sysctl_simple_child, NULL);
+
+	join_thread(pid);
+}
+
+static int sysctl_nested(void *arg)
+{
+	void (*fn)(void) = arg;
+
+	fn();
+	return 0;
+}
+
+static int sysctl_nested_wait(void *arg)
+{
+	int sem = semget(SEM_KEY, 1, 0600);
+	struct sembuf sembuf;
+
+	if (sem < 0) {
+		perror("semget:");
+		abort();
+	}
+	sembuf.sem_num = 0;
+	sembuf.sem_flg = 0;
+	sembuf.sem_op = 0;
+
+	if (semop(sem, &sembuf, 1) < 0) {
+		perror("semop:");
+		abort();
+	}
+
+	return sysctl_nested(arg);
+}
+
+static void test_sysctl_sysctl1_failset(void)
+{
+	sysctl_fail_write("0");
+	test_sysctl_sysctl1();
+}
+
+static void test_sysctl_sysctl2_failset(void)
+{
+	sysctl_fail_write("1");
+	test_sysctl_sysctl2();
+
+	sysctl_fail_write("0");
+	test_sysctl_sysctl2();
+}
+
+static int sysctl_nested_child(void *arg)
+{
+	int pid, sem;
+	union semun semun;
+	struct sembuf sembuf;
+
+	printf("%s nested sysctl 0\n", memfd_str);
+	sysctl_assert_write("0");
+	/* A further nested pidns works the same. */
+	pid = spawn_thread(CLONE_NEWPID, sysctl_simple_child, NULL);
+	join_thread(pid);
+
+	printf("%s nested sysctl 1\n", memfd_str);
+	sysctl_assert_write("1");
+	/* Child inherits our setting. */
+	pid = spawn_thread(CLONE_NEWPID, sysctl_nested, test_sysctl_sysctl1);
+	join_thread(pid);
+	/* Child cannot raise the setting. */
+	pid = spawn_thread(CLONE_NEWPID, sysctl_nested,
+			   test_sysctl_sysctl1_failset);
+	join_thread(pid);
+	/* Child can lower the setting. */
+	pid = spawn_thread(CLONE_NEWPID, sysctl_nested,
+			   test_sysctl_set_sysctl2);
+	join_thread(pid);
+	/* Child lowering the setting has no effect on our setting. */
+	test_sysctl_sysctl1();
+
+	printf("%s nested sysctl 2\n", memfd_str);
+	sysctl_assert_write("2");
+	/* Child inherits our setting. */
+	pid = spawn_thread(CLONE_NEWPID, sysctl_nested, test_sysctl_sysctl2);
+	join_thread(pid);
+	/* Child cannot raise the setting. */
+	pid = spawn_thread(CLONE_NEWPID, sysctl_nested,
+			   test_sysctl_sysctl2_failset);
+	join_thread(pid);
+
+	sem = semget(SEM_KEY, 1, IPC_CREAT | 0600);
+	if (sem < 0) {
+		perror("semget:");
+		return 1;
+	}
+	semun.val = 1;
+	sembuf.sem_op = -1;
+	sembuf.sem_flg = 0;
+	sembuf.sem_num = 0;
+
+	/* Verify that the rules are actually inherited after fork. */
+	printf("%s nested sysctl 0 -> 1 after fork\n", memfd_str);
+	sysctl_assert_write("0");
+
+	if (semctl(sem, 0, SETVAL, semun) < 0) {
+		perror("semctl:");
+		return 1;
+	}
+
+	pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
+			   test_sysctl_sysctl1_failset);
+	sysctl_assert_write("1");
+
+	/* Allow child to continue */
+	if (semop(sem, &sembuf, 1) < 0) {
+		perror("semop:");
+		return 1;
+	}
+	join_thread(pid);
+
+	printf("%s nested sysctl 0 -> 2 after fork\n", memfd_str);
+	sysctl_assert_write("0");
+
+	if (semctl(sem, 0, SETVAL, semun) < 0) {
+		perror("semctl:");
+		return 1;
+	}
+
+	pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
+			   test_sysctl_sysctl2_failset);
+	sysctl_assert_write("2");
+
+	/* Allow child to continue */
+	if (semop(sem, &sembuf, 1) < 0) {
+		perror("semop:");
+		return 1;
+	}
+	join_thread(pid);
+
+	/*
+	 * Verify that the current effective setting is saved on fork, meaning
+	 * that the parent lowering the sysctl doesn't affect already-forked
+	 * children.
+	 */
+	printf("%s nested sysctl 2 -> 1 after fork\n", memfd_str);
+	sysctl_assert_write("2");
+
+	if (semctl(sem, 0, SETVAL, semun) < 0) {
+		perror("semctl:");
+		return 1;
+	}
+
+	pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
+			   test_sysctl_sysctl2);
+	sysctl_assert_write("1");
+
+	/* Allow child to continue */
+	if (semop(sem, &sembuf, 1) < 0) {
+		perror("semop:");
+		return 1;
+	}
+	join_thread(pid);
+
+	printf("%s nested sysctl 2 -> 0 after fork\n", memfd_str);
+	sysctl_assert_write("2");
+
+	if (semctl(sem, 0, SETVAL, semun) < 0) {
+		perror("semctl:");
+		return 1;
+	}
+
+	pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
+			   test_sysctl_sysctl2);
+	sysctl_assert_write("0");
+
+	/* Allow child to continue */
+	if (semop(sem, &sembuf, 1) < 0) {
+		perror("semop:");
+		return 1;
+	}
+	join_thread(pid);
+
+	printf("%s nested sysctl 1 -> 0 after fork\n", memfd_str);
+	sysctl_assert_write("1");
+
+	if (semctl(sem, 0, SETVAL, semun) < 0) {
+		perror("semctl:");
+		return 1;
+	}
+
+	pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
+			   test_sysctl_sysctl1);
+	sysctl_assert_write("0");
+	/* Allow child to continue */
+	if (semop(sem, &sembuf, 1) < 0) {
+		perror("semop:");
+		return 1;
+	}
+	join_thread(pid);
+
+	semctl(sem, 0, IPC_RMID);
+
+	return 0;
+}
+
+/*
+ * Test sysctl with nested pid namespaces
+ * Make sure that the sysctl nesting semantics work correctly.
+ */
+static void test_sysctl_nested(void)
+{
+	int pid = spawn_thread(CLONE_NEWPID, sysctl_nested_child, NULL);
+
+	join_thread(pid);
+}
+
+/*
+ * Test sharing via dup()
+ * Test that seals are shared between dupped FDs and they're all equal.
+ */
+static void test_share_dup(char *banner, char *b_suffix)
+{
+	int fd, fd2;
+
+	printf("%s %s %s\n", memfd_str, banner, b_suffix);
+
+	fd = mfd_assert_new("kern_memfd_share_dup",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
+	mfd_assert_has_seals(fd, 0);
+
+	fd2 = mfd_assert_dup(fd);
+	mfd_assert_has_seals(fd2, 0);
+
+	mfd_assert_add_seals(fd, F_SEAL_WRITE);
+	mfd_assert_has_seals(fd, F_SEAL_WRITE);
+	mfd_assert_has_seals(fd2, F_SEAL_WRITE);
+
+	mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
+	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
+	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
+
+	mfd_assert_add_seals(fd, F_SEAL_SEAL);
+	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
+	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
+
+	mfd_fail_add_seals(fd, F_SEAL_GROW);
+	mfd_fail_add_seals(fd2, F_SEAL_GROW);
+	mfd_fail_add_seals(fd, F_SEAL_SEAL);
+	mfd_fail_add_seals(fd2, F_SEAL_SEAL);
+
+	close(fd2);
+
+	mfd_fail_add_seals(fd, F_SEAL_GROW);
+	close(fd);
+}
+
+/*
+ * Test sealing with active mmap()s
+ * Modifying seals is only allowed if no other mmap() refs exist.
+ */
+static void test_share_mmap(char *banner, char *b_suffix)
+{
+	int fd;
+	void *p;
+
+	printf("%s %s %s\n", memfd_str,  banner, b_suffix);
+
+	fd = mfd_assert_new("kern_memfd_share_mmap",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
+	mfd_assert_has_seals(fd, 0);
+
+	/* shared/writable ref prevents sealing WRITE, but allows others */
+	p = mfd_assert_mmap_shared(fd);
+	mfd_fail_add_seals(fd, F_SEAL_WRITE);
+	mfd_assert_has_seals(fd, 0);
+	mfd_assert_add_seals(fd, F_SEAL_SHRINK);
+	mfd_assert_has_seals(fd, F_SEAL_SHRINK);
+	munmap(p, mfd_def_size);
+
+	/* readable ref allows sealing */
+	p = mfd_assert_mmap_private(fd);
+	mfd_assert_add_seals(fd, F_SEAL_WRITE);
+	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
+	munmap(p, mfd_def_size);
+
+	close(fd);
+}
+
+/*
+ * Test sealing with open(/proc/self/fd/%d)
+ * Via /proc we can get access to a separate file-context for the same memfd.
+ * This is *not* like dup(), but like a real separate open(). Make sure the
+ * semantics are as expected and we correctly check for RDONLY / WRONLY / RDWR.
+ */
+static void test_share_open(char *banner, char *b_suffix)
+{
+	int fd, fd2;
+
+	printf("%s %s %s\n", memfd_str, banner, b_suffix);
+
+	fd = mfd_assert_new("kern_memfd_share_open",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
+	mfd_assert_has_seals(fd, 0);
+
+	fd2 = mfd_assert_open(fd, O_RDWR, 0);
+	mfd_assert_add_seals(fd, F_SEAL_WRITE);
+	mfd_assert_has_seals(fd, F_SEAL_WRITE);
+	mfd_assert_has_seals(fd2, F_SEAL_WRITE);
+
+	mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
+	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
+	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
+
+	close(fd);
+	fd = mfd_assert_open(fd2, O_RDONLY, 0);
+
+	mfd_fail_add_seals(fd, F_SEAL_SEAL);
+	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
+	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
+
+	close(fd2);
+	fd2 = mfd_assert_open(fd, O_RDWR, 0);
+
+	mfd_assert_add_seals(fd2, F_SEAL_SEAL);
+	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
+	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
+
+	close(fd2);
+	close(fd);
+}
+
+/*
+ * Test sharing via fork()
+ * Test whether seal-modifications work as expected with forked children.
+ */
+static void test_share_fork(char *banner, char *b_suffix)
+{
+	int fd;
+	pid_t pid;
+
+	printf("%s %s %s\n", memfd_str, banner, b_suffix);
+
+	fd = mfd_assert_new("kern_memfd_share_fork",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
+	mfd_assert_has_seals(fd, 0);
+
+	pid = spawn_idle_thread(0);
+	mfd_assert_add_seals(fd, F_SEAL_SEAL);
+	mfd_assert_has_seals(fd, F_SEAL_SEAL);
+
+	mfd_fail_add_seals(fd, F_SEAL_WRITE);
+	mfd_assert_has_seals(fd, F_SEAL_SEAL);
+
+	join_idle_thread(pid);
+
+	mfd_fail_add_seals(fd, F_SEAL_WRITE);
+	mfd_assert_has_seals(fd, F_SEAL_SEAL);
+
+	close(fd);
+}
+
+static bool pid_ns_supported(void)
+{
+	return access("/proc/self/ns/pid", F_OK) == 0;
+}
+
+int main(int argc, char **argv)
+{
+	pid_t pid;
+
+	if (argc == 2) {
+		if (!strcmp(argv[1], "hugetlbfs")) {
+			unsigned long hpage_size = default_huge_page_size();
+
+			if (!hpage_size) {
+				printf("Unable to determine huge page size\n");
+				abort();
+			}
+
+			hugetlbfs_test = 1;
+			memfd_str = MEMFD_HUGE_STR;
+			mfd_def_size = hpage_size * 2;
+		} else {
+			printf("Unknown option: %s\n", argv[1]);
+			abort();
+		}
+	}
+
+	test_create();
+	test_basic();
+	test_exec_seal();
+	test_exec_no_seal();
+	test_noexec_seal();
+
+	test_seal_write();
+	test_seal_future_write();
+	test_seal_write_map_read_shared();
+	test_seal_shrink();
+	test_seal_grow();
+	test_seal_resize();
+
+	if (pid_ns_supported()) {
+		test_sysctl_simple();
+		test_sysctl_nested();
+	} else {
+		printf("PID namespaces are not supported; skipping sysctl tests\n");
+	}
+
+	test_share_dup("SHARE-DUP", "");
+	test_share_mmap("SHARE-MMAP", "");
+	test_share_open("SHARE-OPEN", "");
+	test_share_fork("SHARE-FORK", "");
+
+	/* Run test-suite in a multi-threaded environment with a shared
+	 * file-table. */
+	pid = spawn_idle_thread(CLONE_FILES | CLONE_FS | CLONE_VM);
+	test_share_dup("SHARE-DUP", SHARED_FT_STR);
+	test_share_mmap("SHARE-MMAP", SHARED_FT_STR);
+	test_share_open("SHARE-OPEN", SHARED_FT_STR);
+	test_share_fork("SHARE-FORK", SHARED_FT_STR);
+	join_idle_thread(pid);
+
+	printf("memfd: DONE\n");
+
+	return 0;
+}
diff --git a/tools/testing/selftests/memfd/run_fuse_test.sh b/tools/testing/selftests/memfd/run_fuse_test.sh
new file mode 100755
index 000000000..22e572e2d
--- /dev/null
+++ b/tools/testing/selftests/memfd/run_fuse_test.sh
@@ -0,0 +1,15 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+if test -d "./mnt" ; then
+	fusermount -u ./mnt
+	rmdir ./mnt
+fi
+
+set -e
+
+mkdir mnt
+./fuse_mnt ./mnt
+./fuse_test ./mnt/memfd $@
+fusermount -u ./mnt
+rmdir ./mnt
diff --git a/tools/testing/selftests/memfd/run_hugetlbfs_test.sh b/tools/testing/selftests/memfd/run_hugetlbfs_test.sh
new file mode 100755
index 000000000..fb633eeb0
--- /dev/null
+++ b/tools/testing/selftests/memfd/run_hugetlbfs_test.sh
@@ -0,0 +1,68 @@
+#!/bin/bash
+# please run as root
+
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
+
+#
+# To test memfd_create with hugetlbfs, there needs to be hpages_test
+# huge pages free.  Attempt to allocate enough pages to test.
+#
+hpages_test=8
+
+#
+# Get count of free huge pages from /proc/meminfo
+#
+while read name size unit; do
+        if [ "$name" = "HugePages_Free:" ]; then
+                freepgs=$size
+        fi
+done < /proc/meminfo
+
+#
+# If not enough free huge pages for test, attempt to increase
+#
+if [ -n "$freepgs" ] && [ $freepgs -lt $hpages_test ]; then
+	nr_hugepgs=`cat /proc/sys/vm/nr_hugepages`
+	hpages_needed=`expr $hpages_test - $freepgs`
+
+	if [ $UID != 0 ]; then
+		echo "Please run memfd with hugetlbfs test as root"
+		exit $ksft_skip
+	fi
+
+	echo 3 > /proc/sys/vm/drop_caches
+	echo $(( $hpages_needed + $nr_hugepgs )) > /proc/sys/vm/nr_hugepages
+	while read name size unit; do
+		if [ "$name" = "HugePages_Free:" ]; then
+			freepgs=$size
+		fi
+	done < /proc/meminfo
+fi
+
+#
+# If still not enough huge pages available, exit.  But, give back any huge
+# pages potentially allocated above.
+#
+if [ $freepgs -lt $hpages_test ]; then
+	# nr_hugepgs non-zero only if we attempted to increase
+	if [ -n "$nr_hugepgs" ]; then
+		echo $nr_hugepgs > /proc/sys/vm/nr_hugepages
+	fi
+	printf "Not enough huge pages available (%d < %d)\n" \
+		$freepgs $needpgs
+	exit $ksft_skip
+fi
+
+#
+# Run the hugetlbfs test
+#
+./memfd_test hugetlbfs
+./run_fuse_test.sh hugetlbfs
+
+#
+# Give back any huge pages allocated for the test
+#
+if [ -n "$nr_hugepgs" ]; then
+	echo $nr_hugepgs > /proc/sys/vm/nr_hugepages
+fi