diff --git a/test/issues/840/C840.sh b/test/issues/840/C840.sh
new file mode 100644
index 00000000..39b174cc
--- /dev/null
+++ b/test/issues/840/C840.sh
@@ -0,0 +1,152 @@
+#!/bin/sh
+if ! sudo ls /sys/kernel/debug | grep kmemleak > /dev/null 2>&1; then
+	echo kmemleak: not found >&2
+	exit 1
+fi
+
+echo 'C840T01... '
+ng=0
+sync
+sudo /sbin/sysctl vm.drop_caches=3 > /dev/null 2>&1
+./ihkosctl 0 clear_kmsg
+sudo dmesg -c > /dev/null
+sudo sh -c 'echo clear > /sys/kernel/debug/kmemleak'
+./mcexec ./C840T01
+if [ `sudo cat /sys/kernel/debug/kmemleak | wc -l` != 0 ]; then
+	echo 'C840T01: NG (kmemleak)'
+	ng=1
+fi
+if ! dmesg | grep 'remote_page_fault:interrupted. -512' > /dev/null 2>&1; then
+	echo 'C840T01: WARN (remote_page_fault)'
+	ng=1
+fi
+if ! ./ihkosctl 0 kmsg | grep 'is dead, terminate()' > /dev/null 2>&1; then
+	echo 'C840T01: WARN (syscall offloading)'
+	ng=1
+fi
+if [ $ng = 0 ]; then
+	echo C840T01: OK
+fi
+
+echo 'C840T02... '
+ng=0
+sync
+sudo /sbin/sysctl vm.drop_caches=3 > /dev/null 2>&1
+./ihkosctl 0 clear_kmsg
+sudo dmesg -c > /dev/null
+sudo sh -c 'echo clear > /sys/kernel/debug/kmemleak'
+./mcexec ./C840T02
+if [ `sudo cat /sys/kernel/debug/kmemleak | wc -l` != 0 ]; then
+	echo 'C840T02: NG (kmemleak)'
+	ng=1
+fi
+if dmesg | grep 'remote_page_fault:interrupted. -512' > /dev/null 2>&1; then
+	echo 'C840T02: WARN (remote_page_fault)'
+	ng=1
+fi
+if ! ./ihkosctl 0 kmsg | grep 'is dead, terminate()' > /dev/null 2>&1; then
+	echo 'C840T02: WARN (syscall offloading)'
+	ng=1
+fi
+if [ $ng = 0 ]; then
+	echo C840T02: OK
+fi
+
+echo 'C840T03... '
+ng=0
+sync
+sudo /sbin/sysctl vm.drop_caches=3 > /dev/null 2>&1
+./ihkosctl 0 clear_kmsg
+sudo dmesg -c > /dev/null
+sudo sh -c 'echo clear > /sys/kernel/debug/kmemleak'
+./mcexec ./C840T03
+if [ `sudo cat /sys/kernel/debug/kmemleak | wc -l` != 0 ]; then
+	echo 'C840T03: NG (kmemleak)'
+	ng=1
+fi
+if dmesg | grep 'remote_page_fault:interrupted. -512' > /dev/null 2>&1; then
+	echo 'C840T03: WARN (remote_page_fault)'
+	ng=1
+fi
+if ./ihkosctl 0 kmsg | grep 'is dead, terminate()' > /dev/null 2>&1; then
+	echo 'C840T03: WARN (syscall offloading)'
+	ng=1
+fi
+if [ $ng = 0 ]; then
+	echo C840T03: OK
+fi
+
+echo 'C840T04... '
+ng=0
+sync
+sudo /sbin/sysctl vm.drop_caches=3 > /dev/null 2>&1
+./ihkosctl 0 clear_kmsg
+sudo dmesg -c > /dev/null
+sudo sh -c 'echo clear > /sys/kernel/debug/kmemleak'
+timeout -s 9 2 ./mcexec ./C840T04
+sleep 2
+if [ `sudo cat /sys/kernel/debug/kmemleak | wc -l` != 0 ]; then
+	echo 'C840T04: NG (kmemleak)'
+	ng=1
+fi
+if ! dmesg | grep 'remote_page_fault:interrupted. -512' > /dev/null 2>&1; then
+	echo 'C840T04: WARN (remote_page_fault)'
+	ng=1
+fi
+if ! ./ihkosctl 0 kmsg | grep 'is dead, terminate()' > /dev/null 2>&1; then
+	echo 'C840T04: WARN (syscall offloading)'
+	ng=1
+fi
+if [ $ng = 0 ]; then
+	echo C840T04: OK
+fi
+
+echo 'C840T05... '
+ng=0
+sync
+sudo /sbin/sysctl vm.drop_caches=3 > /dev/null 2>&1
+./ihkosctl 0 clear_kmsg
+sudo dmesg -c > /dev/null
+sudo sh -c 'echo clear > /sys/kernel/debug/kmemleak'
+timeout -s 9 2 ./mcexec ./C840T05
+sleep 2
+if [ `sudo cat /sys/kernel/debug/kmemleak | wc -l` != 0 ]; then
+	echo 'C840T05: NG (kmemleak)'
+	ng=1
+fi
+if dmesg | grep 'remote_page_fault:interrupted. -512' > /dev/null 2>&1; then
+	echo 'C840T05: WARN (remote_page_fault)'
+	ng=1
+fi
+if ! ./ihkosctl 0 kmsg | grep 'is dead, terminate()' > /dev/null 2>&1; then
+	echo 'C840T05: WARN (syscall offloading)'
+	ng=1
+fi
+if [ $ng = 0 ]; then
+	echo C840T05: OK
+fi
+
+echo 'C840T06... '
+ng=0
+sync
+sudo /sbin/sysctl vm.drop_caches=3 > /dev/null 2>&1
+./ihkosctl 0 clear_kmsg
+sudo dmesg -c > /dev/null
+sudo sh -c 'echo clear > /sys/kernel/debug/kmemleak'
+timeout -s 9 2 ./mcexec ./C840T06
+sleep 2
+if [ `sudo cat /sys/kernel/debug/kmemleak | wc -l` != 0 ]; then
+	echo 'C840T06: NG (kmemleak)'
+	ng=1
+fi
+if dmesg | grep 'remote_page_fault:interrupted. -512' > /dev/null 2>&1; then
+	echo 'C840T06: WARN (remote_page_fault)'
+	ng=1
+fi
+if ./ihkosctl 0 kmsg | grep 'is dead, terminate()' > /dev/null 2>&1; then
+	echo 'C840T06: WARN (syscall offloading)'
+	ng=1
+fi
+if [ $ng = 0 ]; then
+	echo C840T06: OK
+fi
diff --git a/test/issues/840/C840.txt b/test/issues/840/C840.txt
new file mode 100644
index 00000000..7795e8f6
--- /dev/null
+++ b/test/issues/840/C840.txt
@@ -0,0 +1,28 @@
+スクリプトは Wed Jun  6 14:38:21 2018
+ に開始しました[?1034hbash-4.2$ sh C840.sh
+C840T01... 
+Terminate by signal 9
+C840.sh: 14 行: 22464 強制終了            ./mcexec ./C840T01
+C840T01: OK
+C840T02... 
+Terminate by signal 9
+C840.sh: 38 行: 22500 強制終了            ./mcexec ./C840T02
+C840T02: OK
+C840T03... 
+Terminate by signal 9
+C840.sh: 62 行: 22535 強制終了            ./mcexec ./C840T03
+C840T03: OK
+C840T04... 
+C840.sh: 86 行: 22570 強制終了            timeout -s 9 2 ./mcexec ./C840T04
+C840T04: OK
+C840T05... 
+C840.sh: 111 行: 22598 強制終了            timeout -s 9 2 ./mcexec ./C840T05
+C840T05: OK
+C840T06... 
+C840.sh: 136 行: 22626 強制終了            timeout -s 9 2 ./mcexec ./C840T06
+C840T06: OK
+bash-4.2$ exit
+exit
+
+スクリプトは Wed Jun  6 14:38:51 2018
+ に終了しました
\ No newline at end of file
diff --git a/test/issues/840/C840T01.c b/test/issues/840/C840T01.c
new file mode 100644
index 00000000..9a08565b
--- /dev/null
+++ b/test/issues/840/C840T01.c
@@ -0,0 +1,46 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <errno.h>
+
+int
+main(int argc, char **argv)
+{
+	int fd;
+	void *p;
+	long l;
+	pid_t pid;
+
+	pid = fork();
+	if (pid == 0) {
+		sleep(1);
+		kill(getppid(), SIGKILL);
+		exit(0);
+	}
+
+	fd = open("rpf.data", O_RDONLY);
+	if (fd == -1) {
+		perror("open(rpf.data)");
+		exit(1);
+	}
+	p = mmap(NULL, 512*1024*1024, PROT_READ, MAP_PRIVATE, fd, 0);
+	if (p == (void *)-1) {
+		perror("mmap");
+		exit(1);
+	}
+	close(fd);
+	fd = open("rpf.out", O_WRONLY|O_CREAT|O_TRUNC, 0600);
+	if (fd == -1) {
+		perror("open(fpt.out)");
+		exit(1);
+	}
+	l = write(fd, p, 512*1024*1024);
+	printf("write=%ld\n", l);
+	close(fd);
+	munmap(p, 512*1024*1024);
+	exit(0);
+}
diff --git a/test/issues/840/C840T02.c b/test/issues/840/C840T02.c
new file mode 100644
index 00000000..c62ea7aa
--- /dev/null
+++ b/test/issues/840/C840T02.c
@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <errno.h>
+
+int
+main(int argc, char **argv)
+{
+	pid_t pid;
+	int pfd[2];
+	char c;
+
+	pid = fork();
+	if (pid == 0) {
+		sleep(1);
+		kill(getppid(), SIGKILL);
+		exit(0);
+	}
+
+	pipe(pfd);
+	read(pfd[0], &c, 1);
+	exit(0);
+}
diff --git a/test/issues/840/C840T03.c b/test/issues/840/C840T03.c
new file mode 100644
index 00000000..8878404e
--- /dev/null
+++ b/test/issues/840/C840T03.c
@@ -0,0 +1,24 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <errno.h>
+
+int
+main(int argc, char **argv)
+{
+	pid_t pid;
+
+	pid = fork();
+	if (pid == 0) {
+		sleep(1);
+		kill(getppid(), SIGKILL);
+		exit(0);
+	}
+
+	for(;;);
+	exit(0);
+}
diff --git a/test/issues/840/C840T04.c b/test/issues/840/C840T04.c
new file mode 100644
index 00000000..0a02992f
--- /dev/null
+++ b/test/issues/840/C840T04.c
@@ -0,0 +1,38 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <errno.h>
+
+int
+main(int argc, char **argv)
+{
+	int fd;
+	void *p;
+	long l;
+
+	fd = open("rpf.data", O_RDONLY);
+	if (fd == -1) {
+		perror("open(rpf.data)");
+		exit(1);
+	}
+	p = mmap(NULL, 512*1024*1024, PROT_READ, MAP_PRIVATE, fd, 0);
+	if (p == (void *)-1) {
+		perror("mmap");
+		exit(1);
+	}
+	close(fd);
+	fd = open("rpf.out", O_WRONLY|O_CREAT|O_TRUNC, 0600);
+	if (fd == -1) {
+		perror("open(fpt.out)");
+		exit(1);
+	}
+	l = write(fd, p, 512*1024*1024);
+	printf("write=%ld\n", l);
+	close(fd);
+	munmap(p, 512*1024*1024);
+	exit(0);
+}
diff --git a/test/issues/840/C840T05.c b/test/issues/840/C840T05.c
new file mode 100644
index 00000000..039e5a7c
--- /dev/null
+++ b/test/issues/840/C840T05.c
@@ -0,0 +1,19 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <errno.h>
+
+int
+main(int argc, char **argv)
+{
+	int pfd[2];
+	char c;
+
+	pipe(pfd);
+	read(pfd[0], &c, 1);
+	exit(0);
+}
diff --git a/test/issues/840/C840T06.c b/test/issues/840/C840T06.c
new file mode 100644
index 00000000..b4f2c835
--- /dev/null
+++ b/test/issues/840/C840T06.c
@@ -0,0 +1,15 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <errno.h>
+
+int
+main(int argc, char **argv)
+{
+	for(;;);
+	exit(0);
+}
diff --git a/test/issues/926/C926.c b/test/issues/926/C926.c
new file mode 100644
index 00000000..40b220bd
--- /dev/null
+++ b/test/issues/926/C926.c
@@ -0,0 +1,587 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/wait.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+
+int
+main(int argc, char **argv)
+{
+	pid_t pid1;
+	pid_t pid2;
+	pid_t pid3;
+	int st;
+	int p[2];
+	int shmid;
+	int *sp;
+	key_t key;
+	int valid1;
+	int valid2;
+	int valid3;
+	char c;
+	int result;
+	struct shmid_ds buf;
+
+	key = ftok(argv[0], 0);
+
+	printf("C926T01... ");
+	fflush(stdout);
+	valid1 = 1;
+	valid2 = 2;
+	valid3 = 2;
+	if (socketpair(AF_UNIX, SOCK_STREAM, 0, p) == -1) {
+		perror("socketpair");
+		exit(1);
+	}
+
+	if ((pid1 = fork()) == 0) {
+		close(p[0]);
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		// step 0
+		sp = shmat(shmid, NULL, 0);
+		*sp = 1;
+		// step 1
+		st = *sp == valid1? 1: 0;
+		shmdt(sp);
+		write(p[1], &c, 1);
+		exit(st);
+	}
+
+	if ((pid2 = fork()) == 0) {
+		close(p[1]);
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		// step 2
+		read(p[0], &c, 1);
+		sp = shmat(shmid, NULL, 0);
+		(*sp)++;
+		// step 3
+		st = *sp == valid2? 1: 0;
+		shmdt(sp);
+		// step 4
+		exit(st);
+	}
+
+	close(p[0]);
+	close(p[1]);
+	result = 0;
+	waitpid(pid1, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+	waitpid(pid2, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+
+	if ((pid3 = fork()) == 0) {
+		// step 5
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		sp = shmat(shmid, NULL, 0);
+		st = *sp == valid3? 1: 0;
+		shmdt(sp);
+		exit(st);
+	}
+
+	waitpid(pid3, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+
+	if (result == 3) {
+		printf("OK\n");
+	}
+	else {
+		printf("NG\n");
+	}
+
+	printf("C926T02... ");
+	fflush(stdout);
+	valid1 = 1;
+	valid2 = 2;
+	valid3 = 2;
+	if (socketpair(AF_UNIX, SOCK_STREAM, 0, p) == -1) {
+		perror("socketpair");
+		exit(1);
+	}
+
+	if ((pid1 = fork()) == 0) {
+		close(p[0]);
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		// step 0
+		sp = shmat(shmid, NULL, 0);
+		*sp = 1;
+		// step 1
+		st = *sp == valid1? 1: 0;
+		exit(st);
+	}
+
+	if ((pid2 = fork()) == 0) {
+		close(p[1]);
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		// step 2
+		read(p[0], &c, 1);
+		sp = shmat(shmid, NULL, 0);
+		(*sp)++;
+		// step 3
+		st = *sp == valid2? 1: 0;
+		shmdt(sp);
+		// step 4
+		exit(st);
+	}
+
+	close(p[0]);
+	close(p[1]);
+	result = 0;
+	waitpid(pid1, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+	waitpid(pid2, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+
+	if ((pid3 = fork()) == 0) {
+		// step 5
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		sp = shmat(shmid, NULL, 0);
+		st = *sp == valid3? 1: 0;
+		shmdt(sp);
+		exit(st);
+	}
+
+	waitpid(pid3, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+
+	if (result == 3) {
+		printf("OK\n");
+	}
+	else {
+		printf("NG\n");
+	}
+
+	printf("C926T03... ");
+	fflush(stdout);
+	valid1 = 1;
+	valid2 = 1;
+	valid3 = 1;
+	if (socketpair(AF_UNIX, SOCK_STREAM, 0, p) == -1) {
+		perror("socketpair");
+		exit(1);
+	}
+
+	if ((pid1 = fork()) == 0) {
+		close(p[0]);
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		// step 0
+		sp = shmat(shmid, NULL, 0);
+		*sp = 1;
+		// step 1
+		shmctl(shmid, IPC_RMID, &buf);
+		write(p[1], &c, 1);
+
+		// step3
+		read(p[1], &c, 1);
+		st = *sp == valid1? 1: 0;
+		shmdt(sp);
+		write(p[1], &c, 1);
+		exit(st);
+	}
+
+	if ((pid2 = fork()) == 0) {
+		close(p[1]);
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		// step 2
+		read(p[0], &c, 1);
+		sp = shmat(shmid, NULL, 0);
+		(*sp)++;
+		write(p[0], &c, 1);
+		// step 4
+		read(p[0], &c, 1);
+		st = *sp == valid2? 1: 0;
+		shmdt(sp);
+		exit(st);
+	}
+
+	close(p[0]);
+	close(p[1]);
+	result = 0;
+	waitpid(pid1, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+	waitpid(pid2, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+
+	if ((pid3 = fork()) == 0) {
+		// step 5
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		sp = shmat(shmid, NULL, 0);
+		st = *sp == valid3? 1: 0;
+		shmdt(sp);
+		exit(st);
+	}
+
+	waitpid(pid3, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+
+	if (result == 3) {
+		printf("OK\n");
+	}
+	else {
+		printf("NG\n");
+	}
+
+	printf("C926T04... ");
+	fflush(stdout);
+	valid1 = 1;
+	valid2 = 1;
+	valid3 = 1;
+	if (socketpair(AF_UNIX, SOCK_STREAM, 0, p) == -1) {
+		perror("socketpair");
+		exit(1);
+	}
+
+	if ((pid1 = fork()) == 0) {
+		close(p[0]);
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		// step 0
+		sp = shmat(shmid, NULL, 0);
+		*sp = 1;
+		// step 1
+		shmctl(shmid, IPC_RMID, &buf);
+		write(p[1], &c, 1);
+
+		// step4
+		read(p[1], &c, 1);
+		st = *sp == valid1? 1: 0;
+		shmdt(sp);
+		exit(st);
+	}
+
+	if ((pid2 = fork()) == 0) {
+		close(p[1]);
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		// step 2
+		read(p[0], &c, 1);
+		sp = shmat(shmid, NULL, 0);
+		(*sp)++;
+		// step 3
+		st = *sp == valid2? 1: 0;
+		shmdt(sp);
+		write(p[0], &c, 1);
+		exit(st);
+	}
+
+	close(p[0]);
+	close(p[1]);
+	result = 0;
+	waitpid(pid1, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+	waitpid(pid2, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+
+	if ((pid3 = fork()) == 0) {
+		// step 5
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		sp = shmat(shmid, NULL, 0);
+		st = *sp == valid3? 1: 0;
+		shmdt(sp);
+		exit(st);
+	}
+
+	waitpid(pid3, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+
+	if (result == 3) {
+		printf("OK\n");
+	}
+	else {
+		printf("NG\n");
+	}
+
+	printf("C926T05... ");
+	fflush(stdout);
+	valid1 = 1;
+	valid2 = 1;
+	valid3 = 1;
+	if (socketpair(AF_UNIX, SOCK_STREAM, 0, p) == -1) {
+		perror("socketpair");
+		exit(1);
+	}
+
+	if ((pid1 = fork()) == 0) {
+		close(p[0]);
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		// step 0
+		sp = shmat(shmid, NULL, 0);
+		*sp = 1;
+		// step 1
+		shmctl(shmid, IPC_RMID, &buf);
+		// step2
+		st = *sp == valid1? 1: 0;
+		shmdt(sp);
+		write(p[1], &c, 1);
+		exit(st);
+	}
+
+	if ((pid2 = fork()) == 0) {
+		close(p[1]);
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		// step 3
+		read(p[0], &c, 1);
+		sp = shmat(shmid, NULL, 0);
+		(*sp)++;
+		// step 4
+		st = *sp == valid2? 1: 0;
+		shmdt(sp);
+		exit(st);
+	}
+
+	close(p[0]);
+	close(p[1]);
+	result = 0;
+	waitpid(pid1, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+	waitpid(pid2, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+
+	if ((pid3 = fork()) == 0) {
+		// step 5
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		sp = shmat(shmid, NULL, 0);
+		st = *sp == valid3? 1: 0;
+		shmdt(sp);
+		exit(st);
+	}
+
+	waitpid(pid3, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+
+	if (result == 3) {
+		printf("OK\n");
+	}
+	else {
+		printf("NG\n");
+	}
+
+	printf("C926T06... ");
+	fflush(stdout);
+	valid1 = 1;
+	valid2 = 1;
+	valid3 = 1;
+	if (socketpair(AF_UNIX, SOCK_STREAM, 0, p) == -1) {
+		perror("socketpair");
+		exit(1);
+	}
+
+	if ((pid1 = fork()) == 0) {
+		close(p[0]);
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		// step 0
+		sp = shmat(shmid, NULL, 0);
+		*sp = 1;
+		// step 1
+		shmctl(shmid, IPC_RMID, &buf);
+		// step2
+		st = *sp == valid1? 1: 0;
+		exit(st);
+	}
+
+	if ((pid2 = fork()) == 0) {
+		close(p[1]);
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		// step 3
+		read(p[0], &c, 1);
+		sp = shmat(shmid, NULL, 0);
+		(*sp)++;
+		// step 4
+		st = *sp == valid2? 1: 0;
+		shmdt(sp);
+		exit(st);
+	}
+
+	close(p[0]);
+	close(p[1]);
+	result = 0;
+	waitpid(pid1, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+	waitpid(pid2, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+
+	if ((pid3 = fork()) == 0) {
+		// step 5
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		sp = shmat(shmid, NULL, 0);
+		st = *sp == valid3? 1: 0;
+		shmdt(sp);
+		exit(st);
+	}
+
+	waitpid(pid3, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+
+	if (result == 3) {
+		printf("OK\n");
+	}
+	else {
+		printf("NG\n");
+	}
+
+	printf("C926T07... ");
+	fflush(stdout);
+	valid1 = 2;
+	valid2 = 2;
+	valid3 = 0;
+	if (socketpair(AF_UNIX, SOCK_STREAM, 0, p) == -1) {
+		perror("socketpair");
+		exit(1);
+	}
+
+	if ((pid1 = fork()) == 0) {
+		close(p[0]);
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		// step 0
+		sp = shmat(shmid, NULL, 0);
+		*sp = 1;
+		write(p[1], &c, 1);
+		// step 2
+		read(p[1], &c, 1);
+		shmctl(shmid, IPC_RMID, &buf);
+		// step2
+		st = *sp == valid1? 1: 0;
+		exit(st);
+	}
+
+	if ((pid2 = fork()) == 0) {
+		close(p[1]);
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		// step 1
+		read(p[0], &c, 1);
+		sp = shmat(shmid, NULL, 0);
+		(*sp)++;
+		write(p[0], &c, 1);
+		// step 3
+		read(p[0], &c, 1);
+		st = *sp == valid2? 1: 0;
+		shmdt(sp);
+		// step 4
+		exit(st);
+	}
+
+	close(p[0]);
+	close(p[1]);
+	result = 0;
+	waitpid(pid1, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+	waitpid(pid2, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+
+	if ((pid3 = fork()) == 0) {
+		// step 5
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		sp = shmat(shmid, NULL, 0);
+		st = *sp == valid3? 1: 0;
+		shmdt(sp);
+		exit(st);
+	}
+
+	waitpid(pid3, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+
+	if (result == 3) {
+		printf("OK\n");
+	}
+	else {
+		printf("NG\n");
+	}
+
+	printf("C926T08... ");
+	fflush(stdout);
+	valid1 = 2;
+	valid2 = 2;
+	valid3 = 2;
+	if (socketpair(AF_UNIX, SOCK_STREAM, 0, p) == -1) {
+		perror("socketpair");
+		exit(1);
+	}
+
+	if ((pid1 = fork()) == 0) {
+		close(p[0]);
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		// step 0
+		sp = shmat(shmid, NULL, 0);
+		*sp = 1;
+		write(p[1], &c, 1);
+		// step 2
+		read(p[1], &c, 1);
+		// step2
+		st = *sp == valid1? 1: 0;
+		exit(st);
+	}
+
+	if ((pid2 = fork()) == 0) {
+		close(p[1]);
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		// step 1
+		read(p[0], &c, 1);
+		sp = shmat(shmid, NULL, 0);
+		(*sp)++;
+		write(p[0], &c, 1);
+		// step 3
+		read(p[0], &c, 1);
+		st = *sp == valid2? 1: 0;
+		shmdt(sp);
+		// step 4
+		exit(st);
+	}
+
+	close(p[0]);
+	close(p[1]);
+	result = 0;
+	waitpid(pid1, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+	waitpid(pid2, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+
+	if ((pid3 = fork()) == 0) {
+		// step 5
+		shmid = shmget(key, 4096, IPC_CREAT | 0660);
+		sp = shmat(shmid, NULL, 0);
+		st = *sp == valid3? 1: 0;
+		shmdt(sp);
+		exit(st);
+	}
+
+	waitpid(pid3, &st, 0);
+	if (WIFEXITED(st))
+		result += WEXITSTATUS(st);
+
+	if (result == 3) {
+		printf("OK\n");
+	}
+	else {
+		printf("NG\n");
+	}
+
+	exit(0);
+}
diff --git a/test/issues/926/C926.txt b/test/issues/926/C926.txt
new file mode 100644
index 00000000..f77bf070
--- /dev/null
+++ b/test/issues/926/C926.txt
@@ -0,0 +1,15 @@
+スクリプトは Wed Jun  6 14:39:24 2018
+ に開始しました[?1034hbash-4.2$ ./mcexec C./C926
+C926T01... OK
+C926T02... OK
+C926T03... OK
+C926T04... OK
+C926T05... OK
+C926T06... OK
+C926T07... OK
+C926T08... OK
+bash-4.2$ exit
+exit
+
+スクリプトは Wed Jun  6 14:39:38 2018
+ に終了しました
\ No newline at end of file