From: Andrei Vagin <redacted>

This test checks that process_vmsplice() can splice pages from a remote
process and returns EFAULT, if process_vmsplice() tries to splice pages
by an unaccessiable address.

Signed-off-by: Andrei Vagin <redacted>
---
 tools/testing/selftests/process_vmsplice/Makefile  |   5 +
 .../process_vmsplice/process_vmsplice_test.c       | 188 +++++++++++++++++++++
 2 files changed, 193 insertions(+)
 create mode 100644 tools/testing/selftests/process_vmsplice/Makefile
 create mode 100644 tools/testing/selftests/process_vmsplice/process_vmsplice_test.c

diff --git a/tools/testing/selftests/process_vmsplice/Makefile b/tools/testing/selftests/process_vmsplice/Makefile
new file mode 100644
index 0000000..246d5a7
--- /dev/null
+++ b/tools/testing/selftests/process_vmsplice/Makefile

@@ -0,0 +1,5 @@
+CFLAGS += -I../../../../usr/include/
+
+TEST_GEN_PROGS := process_vmsplice_test
+
+include ../lib.mk

diff --git a/tools/testing/selftests/process_vmsplice/process_vmsplice_test.c b/tools/testing/selftests/process_vmsplice/process_vmsplice_test.c
new file mode 100644
index 0000000..8abf59b
--- /dev/null
+++ b/tools/testing/selftests/process_vmsplice/process_vmsplice_test.c

@@ -0,0 +1,188 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <sys/syscall.h>
+#include <fcntl.h>
+#include <sys/uio.h>
+#include <errno.h>
+#include <signal.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
+
+#include "../kselftest.h"
+
+#ifndef __NR_process_vmsplice
+#define __NR_process_vmsplice 333
+#endif
+
+#define pr_err(fmt, ...) \
+		({ \
+			fprintf(stderr, "%s:%d:" fmt, \
+				__func__, __LINE__, ##__VA_ARGS__); \
+			KSFT_FAIL; \
+		})
+#define pr_perror(fmt, ...) pr_err(fmt ": %m\n", ##__VA_ARGS__)
+#define fail(fmt, ...) pr_err("FAIL:" fmt, ##__VA_ARGS__)
+
+static ssize_t process_vmsplice(pid_t pid, int fd, const struct iovec *iov,
+			unsigned long nr_segs, unsigned int flags)
+{
+	return syscall(__NR_process_vmsplice, pid, fd, iov, nr_segs, flags);
+
+}
+
+#define MEM_SIZE (4096 * 100)
+#define MEM_WRONLY_SIZE (4096 * 10)
+
+int main(int argc, char **argv)
+{
+	char *addr, *addr_wronly;
+	int p[2];
+	struct iovec iov[2];
+	char buf[4096];
+	int status, ret;
+	pid_t pid;
+
+	ksft_print_header();
+
+	addr = mmap(0, MEM_SIZE, PROT_READ | PROT_WRITE,
+					MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+	if (addr == MAP_FAILED)
+		return pr_perror("Unable to create a mapping");
+
+	addr_wronly = mmap(0, MEM_WRONLY_SIZE, PROT_WRITE,
+				MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+	if (addr_wronly == MAP_FAILED)
+		return pr_perror("Unable to create a write-only mapping");
+
+	if (pipe(p))
+		return pr_perror("Unable to create a pipe");
+
+	pid = fork();
+	if (pid < 0)
+		return pr_perror("Unable to fork");
+
+	if (pid == 0) {
+		addr[0] = 'C';
+		addr[4096 + 128] = 'A';
+		addr[4096 + 128 + 4096 - 1] = 'B';
+
+		if (prctl(PR_SET_PDEATHSIG, SIGKILL))
+			return pr_perror("Unable to set PR_SET_PDEATHSIG");
+		if (write(p[1], "c", 1) != 1)
+			return pr_perror("Unable to write data into pipe");
+
+		while (1)
+			sleep(1);
+		return 1;
+	}
+	if (read(p[0], buf, 1) != 1) {
+		pr_perror("Unable to read data from pipe");
+		kill(pid, SIGKILL);
+		wait(&status);
+		return 1;
+	}
+
+	munmap(addr, MEM_SIZE);
+	munmap(addr_wronly, MEM_WRONLY_SIZE);
+
+	iov[0].iov_base = addr;
+	iov[0].iov_len = 1;
+
+	iov[1].iov_base = addr + 4096 + 128;
+	iov[1].iov_len = 4096;
+
+	/* check one iovec */
+	if (process_vmsplice(pid, p[1], iov, 1, SPLICE_F_GIFT) != 1)
+		return pr_perror("Unable to splice pages");