git: 4d0adee4e678 - main - stress2: Added procctl(2) PROC_REAP_KILL regression tests

From: Peter Holm <pho_at_FreeBSD.org>
Date: Wed, 01 Jun 2022 08:04:08 UTC
The branch main has been updated by pho:

URL: https://cgit.FreeBSD.org/src/commit/?id=4d0adee4e678d1e1b973fd7cf0650950f609a44b

commit 4d0adee4e678d1e1b973fd7cf0650950f609a44b
Author:     Peter Holm <pho@FreeBSD.org>
AuthorDate: 2022-06-01 07:58:28 +0000
Commit:     Peter Holm <pho@FreeBSD.org>
CommitDate: 2022-06-01 07:58:28 +0000

    stress2: Added procctl(2) PROC_REAP_KILL regression tests
---
 tools/test/stress2/misc/reaper2.sh     | 131 ++++++++++
 tools/test/stress2/misc/reaper3.sh     | 155 +++++++++++
 tools/test/stress2/misc/reaper4.sh     | 154 +++++++++++
 tools/test/stress2/misc/reaper5.sh     |  40 +++
 tools/test/stress2/misc/syzkaller52.sh | 458 +++++++++++++++++++++++++++++++++
 tools/test/stress2/misc/syzkaller53.sh | 172 +++++++++++++
 6 files changed, 1110 insertions(+)

diff --git a/tools/test/stress2/misc/reaper2.sh b/tools/test/stress2/misc/reaper2.sh
new file mode 100755
index 000000000000..8290e38d34e4
--- /dev/null
+++ b/tools/test/stress2/misc/reaper2.sh
@@ -0,0 +1,131 @@
+#!/bin/sh
+
+#
+# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+#
+# Copyright (c) 2022 Peter Holm <pho@FreeBSD.org>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+
+# procctl(2) threaded test
+
+# panic: exiting process is stopped" seen:
+# https://people.freebsd.org/~pho/stress/log/log0285.txt
+
+prog=`basename ${0%.sh}`
+cat > /tmp/$prog.c <<EOF
+#include <sys/param.h>
+#include <sys/mman.h>
+#include <sys/procctl.h>
+
+#include <err.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+
+static volatile u_int *share;
+
+#define PARALLEL 25
+#define RUNTIME 120
+
+static void *
+tr(void *arg __unused)
+{
+	for (;;)
+		pause();
+
+	return (NULL);
+}
+
+static void
+test(void) {
+	pthread_t thr;
+	struct procctl_reaper_kill killemall;
+	pid_t pid;
+	time_t start;
+	int data[20], e, n, m;
+
+	n = m = 0;
+	if (procctl(P_PID, getpid(), PROC_REAP_ACQUIRE, NULL) == -1)
+		err(EXIT_FAILURE, "Fail to acquire the reaper");
+	start = time(NULL);
+	while (time(NULL) - start < RUNTIME) {
+		m++;
+		share[0] = 0;
+		if ((pid = fork()) == 0) {
+			e = pthread_create(&thr, NULL, tr, NULL);
+			if (e != 0)
+				errc(1, e, "pthread_create");
+			share[0] = 1;
+			setproctitle("child");
+			usleep(arc4random() % 200);
+			_exit(0);
+		}
+		arc4random_buf(data, sizeof(data));
+		while (share[0] == 0)
+			usleep(10);
+		killemall.rk_sig = SIGTERM;
+		killemall.rk_flags = 0;
+		if (procctl(P_PID, getpid(), PROC_REAP_KILL,
+		    &killemall) == 0)
+			n++;
+		if (waitpid(pid, NULL, 0) != pid)
+			err(1, "waitpid()");
+	}
+#if defined(DEBUG)
+	fprintf(stderr, "n = %d out of %d\n", n, m);
+#endif
+	_exit(0);
+}
+
+int
+main(void) {
+	pid_t pids[PARALLEL];
+	size_t len;
+	int i;
+
+	len = PAGE_SIZE;
+	if ((share = mmap(NULL, len, PROT_READ | PROT_WRITE,
+	    MAP_ANON | MAP_SHARED, -1, 0)) == MAP_FAILED)
+		err(1, "mmap");
+	for (i = 0; i < PARALLEL; i++) {
+		if ((pids[i] = fork()) == 0)
+			test();
+	}
+	for (i = 0; i < PARALLEL; i++)
+		if (waitpid(pids[i], NULL, 0) != pids[i])
+			err(1, "waitpid()");
+}
+EOF
+cc -o /tmp/$prog -Wall -Wextra -O0 /tmp/$prog.c -lpthread || exit 1
+rm /tmp/$prog.c
+
+here=`pwd`
+cd /tmp
+./$prog; s=$?
+cd $here
+
+rm /tmp/$prog
+exit $s 
diff --git a/tools/test/stress2/misc/reaper3.sh b/tools/test/stress2/misc/reaper3.sh
new file mode 100755
index 000000000000..fdf715fa7b0b
--- /dev/null
+++ b/tools/test/stress2/misc/reaper3.sh
@@ -0,0 +1,155 @@
+#!/bin/sh
+
+#
+# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+#
+# Copyright (c) 2022 Peter Holm <pho@FreeBSD.org>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+
+# procctl(2) fuzz test
+
+prog=`basename ${0%.sh}`
+cat > /tmp/$prog.c <<EOF
+#include <sys/param.h>
+#include <sys/mman.h>
+#include <sys/procctl.h>
+
+#include <err.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+
+static volatile u_int *share;
+
+#define PARALLEL 25
+#define RUNTIME 120
+
+static long
+random_long(long mi, long ma)
+{
+        return (arc4random()  % (ma - mi + 1) + mi);
+}
+
+static void
+flip(void *ap, size_t len)
+{
+	unsigned char *cp;
+	int byte;
+	unsigned char bit, buf, mask, old __unused;
+
+	cp = (unsigned char *)ap;
+	byte = random_long(0, len);
+	bit = random_long(0,7);
+	mask = ~(1 << bit);
+	buf = cp[byte];
+	old = cp[byte];
+	buf = (buf & mask) | (~buf & ~mask);
+	cp[byte] = buf;
+}
+
+static void *
+tr(void *arg __unused)
+{
+	for (;;)
+		pause();
+
+	return (NULL);
+}
+
+static void
+test(void) {
+	pthread_t thr;
+	struct procctl_reaper_kill killemall;
+	pid_t pid;
+	time_t start;
+	int data[20], e, n, m;
+
+	n = m = 0;
+	if (procctl(P_PID, getpid(), PROC_REAP_ACQUIRE, NULL) == -1)
+		err(EXIT_FAILURE, "Fail to acquire the reaper");
+	start = time(NULL);
+	while (time(NULL) - start < RUNTIME) {
+		m++;
+		share[0] = 0;
+		if ((pid = fork()) == 0) {
+			e = pthread_create(&thr, NULL, tr, NULL);
+			if (e != 0)
+				errc(1, e, "pthread_create");
+			share[0] = 1;
+			setproctitle("child");
+			usleep(arc4random() % 200);
+			if (arc4random() % 100 < 2)
+				raise(SIGSEGV);
+			_exit(0);
+		}
+		arc4random_buf(data, sizeof(data));
+		while (share[0] == 0)
+			usleep(10);
+		killemall.rk_sig = SIGTERM;
+		killemall.rk_flags = 0;
+		flip(&killemall, sizeof(killemall));
+		if (procctl(P_PID, getpid(), PROC_REAP_KILL,
+		    &killemall) == 0)
+			n++;
+		if (waitpid(pid, NULL, 0) != pid)
+			err(1, "waitpid()");
+	}
+#if defined(DEBUG)
+	fprintf(stderr, "n = %d out of %d\n", n, m);
+#endif
+	_exit(0);
+}
+
+int
+main(void) {
+	pid_t pids[PARALLEL];
+	size_t len;
+	int i;
+
+	len = PAGE_SIZE;
+	if ((share = mmap(NULL, len, PROT_READ | PROT_WRITE,
+	    MAP_ANON | MAP_SHARED, -1, 0)) == MAP_FAILED)
+		err(1, "mmap");
+	for (i = 0; i < PARALLEL; i++) {
+		if ((pids[i] = fork()) == 0)
+			test();
+	}
+	for (i = 0; i < PARALLEL; i++)
+		if (waitpid(pids[i], NULL, 0) != pids[i])
+			err(1, "waitpid()");
+}
+EOF
+cc -o /tmp/$prog -Wall -Wextra -O0 /tmp/$prog.c -lpthread || exit 1
+rm /tmp/$prog.c
+
+here=`pwd`
+cd /tmp
+./$prog; s=$?
+cd $here
+
+rm -f /tmp/$prog /tmp/$prog.core
+exit $s 
diff --git a/tools/test/stress2/misc/reaper4.sh b/tools/test/stress2/misc/reaper4.sh
new file mode 100755
index 000000000000..bf400e396e63
--- /dev/null
+++ b/tools/test/stress2/misc/reaper4.sh
@@ -0,0 +1,154 @@
+#!/bin/sh
+
+#
+# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+#
+# Copyright (c) 2022 Peter Holm <pho@FreeBSD.org>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+
+# procctl(2) fuzz test
+
+prog=`basename ${0%.sh}`
+cat > /tmp/$prog.c <<EOF
+#include <sys/param.h>
+#include <sys/mman.h>
+#include <sys/procctl.h>
+
+#include <err.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+
+static volatile u_int *share;
+
+#define PARALLEL 25
+#define RUNTIME 120
+
+static long
+random_long(long mi, long ma)
+{
+        return (arc4random()  % (ma - mi + 1) + mi);
+}
+
+static void
+flip(void *ap, size_t len)
+{
+	unsigned char *cp;
+	int byte;
+	unsigned char bit, buf, mask, old __unused;
+
+	cp = (unsigned char *)ap;
+	byte = random_long(0, len);
+	bit = random_long(0,7);
+	mask = ~(1 << bit);
+	buf = cp[byte];
+	old = cp[byte];
+	buf = (buf & mask) | (~buf & ~mask);
+	cp[byte] = buf;
+}
+
+static void *
+tr(void *arg __unused)
+{
+	usleep(arc4random() % 400);
+
+	return (NULL);
+}
+
+static void
+test(void) {
+	pthread_t thr;
+	struct procctl_reaper_kill killemall;
+	pid_t pid;
+	time_t start;
+	int data[20], e, n, m;
+
+	n = m = 0;
+	if (procctl(P_PID, getpid(), PROC_REAP_ACQUIRE, NULL) == -1)
+		err(EXIT_FAILURE, "Fail to acquire the reaper");
+	start = time(NULL);
+	while (time(NULL) - start < RUNTIME) {
+		m++;
+		share[0] = 0;
+		if ((pid = fork()) == 0) {
+			e = pthread_create(&thr, NULL, tr, NULL);
+			if (e != 0)
+				errc(1, e, "pthread_create");
+			share[0] = 1;
+			setproctitle("child");
+			usleep(arc4random() % 200);
+			if (arc4random() % 100 < 2)
+				raise(SIGSEGV);
+			_exit(0);
+		}
+		arc4random_buf(data, sizeof(data));
+		while (share[0] == 0)
+			usleep(10);
+		killemall.rk_sig = SIGTERM;
+		killemall.rk_flags = 0;
+		flip(&killemall, sizeof(killemall));
+		if (procctl(P_PID, getpid(), PROC_REAP_KILL,
+		    &killemall) == 0)
+			n++;
+		if (waitpid(pid, NULL, 0) != pid)
+			err(1, "waitpid()");
+	}
+#if defined(DEBUG)
+	fprintf(stderr, "n = %d out of %d\n", n, m);
+#endif
+	_exit(0);
+}
+
+int
+main(void) {
+	pid_t pids[PARALLEL];
+	size_t len;
+	int i;
+
+	len = PAGE_SIZE;
+	if ((share = mmap(NULL, len, PROT_READ | PROT_WRITE,
+	    MAP_ANON | MAP_SHARED, -1, 0)) == MAP_FAILED)
+		err(1, "mmap");
+	for (i = 0; i < PARALLEL; i++) {
+		if ((pids[i] = fork()) == 0)
+			test();
+	}
+	for (i = 0; i < PARALLEL; i++)
+		if (waitpid(pids[i], NULL, 0) != pids[i])
+			err(1, "waitpid()");
+}
+EOF
+cc -o /tmp/$prog -Wall -Wextra -O0 /tmp/$prog.c -lpthread || exit 1
+rm /tmp/$prog.c
+
+here=`pwd`
+cd /tmp
+./$prog; s=$?
+cd $here
+
+rm -f /tmp/$prog /tmp/$prog.core
+exit $s 
diff --git a/tools/test/stress2/misc/reaper5.sh b/tools/test/stress2/misc/reaper5.sh
new file mode 100755
index 000000000000..eec58c36713a
--- /dev/null
+++ b/tools/test/stress2/misc/reaper5.sh
@@ -0,0 +1,40 @@
+#!/bin/sh
+
+#
+# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+#
+# Copyright (c) 2022 Peter Holm <pho@FreeBSD.org>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+
+# "panic: Assertion (t->parent->p_treeflag & P_TREE_REAPER) != 0 failed at
+# ../../../kern/kern_procctl.c:373" seen in WiP kernel code
+
+start=`date +%s`
+while [ $((`date +%s` - start)) -lt 120 ]; do
+	for i in `jot 100`; do
+		timeout 2s sh -c "timeout 2s sleep 60" &
+	done
+	wait
+done
+exit 0
diff --git a/tools/test/stress2/misc/syzkaller52.sh b/tools/test/stress2/misc/syzkaller52.sh
new file mode 100755
index 000000000000..ec5244bdae65
--- /dev/null
+++ b/tools/test/stress2/misc/syzkaller52.sh
@@ -0,0 +1,458 @@
+#!/bin/sh
+
+# panic: already suspended
+# cpuid = 6
+# time = 1651176216
+# KDB: stack backtrace:
+# db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe014194ea70
+# vpanic() at vpanic+0x17f/frame 0xfffffe014194eac0
+# panic() at panic+0x43/frame 0xfffffe014194eb20
+# thread_single() at thread_single+0x774/frame 0xfffffe014194eb90
+# reap_kill_proc() at reap_kill_proc+0x296/frame 0xfffffe014194ebf0
+# reap_kill() at reap_kill+0x371/frame 0xfffffe014194ed00
+# kern_procctl() at kern_procctl+0x30b/frame 0xfffffe014194ed70
+# sys_procctl() at sys_procctl+0x11e/frame 0xfffffe014194ee00
+# amd64_syscall() at amd64_syscall+0x145/frame 0xfffffe014194ef30
+# fast_syscall_common() at fast_syscall_common+0xf8/frame 0xfffffe014194ef30
+# --- syscall (0, FreeBSD ELF64, nosys), rip = 0x8226f27aa, rsp = 0x82803ef48, rbp = 0x82803ef70 ---
+# KDB: enter: panic
+# [ thread pid 3074 tid 100404 ]
+# Stopped at      kdb_enter+0x32: movq    $0,0x12790b3(%rip)
+# db> x/s version
+# FreeBSD 14.0-CURRENT #0 main-n255099-0923ff82fb383: Thu Apr 28 09:48:48 CEST 2022
+# pho@mercat1.netperf.freebsd.org:/usr/src/sys/amd64/compile/PHO
+# db>
+
+[ `uname -p` != "amd64" ] && exit 0
+
+. ../default.cfg
+cat > /tmp/syzkaller52.c <<EOF
+// https://syzkaller.appspot.com/bug?id=20185b6047d7371885412b56ff188be88f740eab
+// autogenerated by syzkaller (https://github.com/google/syzkaller)
+// Reported-by: syzbot+79cd12371d417441b175@syzkaller.appspotmail.com
+
+#define _GNU_SOURCE
+
+#include <sys/types.h>
+
+#include <dirent.h>
+#include <errno.h>
+#include <pthread.h>
+#include <pwd.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/endian.h>
+#include <sys/resource.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/wait.h>
+#include <time.h>
+#include <unistd.h>
+
+static unsigned long long procid;
+
+static void kill_and_wait(int pid, int* status)
+{
+  kill(pid, SIGKILL);
+  while (waitpid(-1, status, 0) != pid) {
+  }
+}
+
+static void sleep_ms(uint64_t ms)
+{
+  usleep(ms * 1000);
+}
+
+static uint64_t current_time_ms(void)
+{
+  struct timespec ts;
+  if (clock_gettime(CLOCK_MONOTONIC, &ts))
+    exit(1);
+  return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
+}
+
+static void use_temporary_dir(void)
+{
+  char tmpdir_template[] = "./syzkaller.XXXXXX";
+  char* tmpdir = mkdtemp(tmpdir_template);
+  if (!tmpdir)
+    exit(1);
+  if (chmod(tmpdir, 0777))
+    exit(1);
+  if (chdir(tmpdir))
+    exit(1);
+}
+
+static void __attribute__((noinline)) remove_dir(const char* dir)
+{
+  DIR* dp = opendir(dir);
+  if (dp == NULL) {
+    if (errno == EACCES) {
+      if (rmdir(dir))
+        exit(1);
+      return;
+    }
+    exit(1);
+  }
+  struct dirent* ep = 0;
+  while ((ep = readdir(dp))) {
+    if (strcmp(ep->d_name, ".") == 0 || strcmp(ep->d_name, "..") == 0)
+      continue;
+    char filename[FILENAME_MAX];
+    snprintf(filename, sizeof(filename), "%s/%s", dir, ep->d_name);
+    struct stat st;
+    if (lstat(filename, &st))
+      exit(1);
+    if (S_ISDIR(st.st_mode)) {
+      remove_dir(filename);
+      continue;
+    }
+    if (unlink(filename))
+      exit(1);
+  }
+  closedir(dp);
+  if (rmdir(dir))
+    exit(1);
+}
+
+static void thread_start(void* (*fn)(void*), void* arg)
+{
+  pthread_t th;
+  pthread_attr_t attr;
+  pthread_attr_init(&attr);
+  pthread_attr_setstacksize(&attr, 128 << 10);
+  int i = 0;
+  for (; i < 100; i++) {
+    if (pthread_create(&th, &attr, fn, arg) == 0) {
+      pthread_attr_destroy(&attr);
+      return;
+    }
+    if (errno == EAGAIN) {
+      usleep(50);
+      continue;
+    }
+    break;
+  }
+  exit(1);
+}
+
+typedef struct {
+  pthread_mutex_t mu;
+  pthread_cond_t cv;
+  int state;
+} event_t;
+
+static void event_init(event_t* ev)
+{
+  if (pthread_mutex_init(&ev->mu, 0))
+    exit(1);
+  if (pthread_cond_init(&ev->cv, 0))
+    exit(1);
+  ev->state = 0;
+}
+
+static void event_reset(event_t* ev)
+{
+  ev->state = 0;
+}
+
+static void event_set(event_t* ev)
+{
+  pthread_mutex_lock(&ev->mu);
+  if (ev->state)
+    exit(1);
+  ev->state = 1;
+  pthread_mutex_unlock(&ev->mu);
+  pthread_cond_broadcast(&ev->cv);
+}
+
+static void event_wait(event_t* ev)
+{
+  pthread_mutex_lock(&ev->mu);
+  while (!ev->state)
+    pthread_cond_wait(&ev->cv, &ev->mu);
+  pthread_mutex_unlock(&ev->mu);
+}
+
+static int event_isset(event_t* ev)
+{
+  pthread_mutex_lock(&ev->mu);
+  int res = ev->state;
+  pthread_mutex_unlock(&ev->mu);
+  return res;
+}
+
+static int event_timedwait(event_t* ev, uint64_t timeout)
+{
+  uint64_t start = current_time_ms();
+  uint64_t now = start;
+  pthread_mutex_lock(&ev->mu);
+  for (;;) {
+    if (ev->state)
+      break;
+    uint64_t remain = timeout - (now - start);
+    struct timespec ts;
+    ts.tv_sec = remain / 1000;
+    ts.tv_nsec = (remain % 1000) * 1000 * 1000;
+    pthread_cond_timedwait(&ev->cv, &ev->mu, &ts);
+    now = current_time_ms();
+    if (now - start > timeout)
+      break;
+  }
+  int res = ev->state;
+  pthread_mutex_unlock(&ev->mu);
+  return res;
+}
+
+static void sandbox_common()
+{
+  struct rlimit rlim;
+  rlim.rlim_cur = rlim.rlim_max = 128 << 20;
+  setrlimit(RLIMIT_AS, &rlim);
+  rlim.rlim_cur = rlim.rlim_max = 8 << 20;
+  setrlimit(RLIMIT_MEMLOCK, &rlim);
+  rlim.rlim_cur = rlim.rlim_max = 1 << 20;
+  setrlimit(RLIMIT_FSIZE, &rlim);
+  rlim.rlim_cur = rlim.rlim_max = 1 << 20;
+  setrlimit(RLIMIT_STACK, &rlim);
+  rlim.rlim_cur = rlim.rlim_max = 0;
+  setrlimit(RLIMIT_CORE, &rlim);
+  rlim.rlim_cur = rlim.rlim_max = 256;
+  setrlimit(RLIMIT_NOFILE, &rlim);
+}
+
+static void loop();
+
+static int do_sandbox_none(void)
+{
+  sandbox_common();
+  loop();
+  return 0;
+}
+
+struct thread_t {
+  int created, call;
+  event_t ready, done;
+};
+
+static struct thread_t threads[16];
+static void execute_call(int call);
+static int running;
+
+static void* thr(void* arg)
+{
+  struct thread_t* th = (struct thread_t*)arg;
+  for (;;) {
+    event_wait(&th->ready);
+    event_reset(&th->ready);
+    execute_call(th->call);
+    __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED);
+    event_set(&th->done);
+  }
+  return 0;
+}
+
+static void execute_one(void)
+{
+  int i, call, thread;
+  for (call = 0; call < 14; call++) {
+    for (thread = 0; thread < (int)(sizeof(threads) / sizeof(threads[0]));
+         thread++) {
+      struct thread_t* th = &threads[thread];
+      if (!th->created) {
+        th->created = 1;
+        event_init(&th->ready);
+        event_init(&th->done);
+        event_set(&th->done);
+        thread_start(thr, th);
+      }
+      if (!event_isset(&th->done))
+        continue;
+      event_reset(&th->done);
+      th->call = call;
+      __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
+      event_set(&th->ready);
+      event_timedwait(&th->done, 50);
+      break;
+    }
+  }
+  for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++)
+    sleep_ms(1);
+}
+
+static void execute_one(void);
+
+#define WAIT_FLAGS 0
+
+static void loop(void)
+{
+  int iter = 0;
+  for (;; iter++) {
+    char cwdbuf[32];
+    sprintf(cwdbuf, "./%d", iter);
+    if (mkdir(cwdbuf, 0777))
+      exit(1);
+    int pid = fork();
+    if (pid < 0)
+      exit(1);
+    if (pid == 0) {
+      if (chdir(cwdbuf))
+        exit(1);
+      execute_one();
+      exit(0);
+    }
+    int status = 0;
+    uint64_t start = current_time_ms();
+    for (;;) {
+      if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid)
+        break;
+      sleep_ms(1);
+      if (current_time_ms() - start < 5000)
+        continue;
+      kill_and_wait(pid, &status);
+      break;
+    }
+    remove_dir(cwdbuf);
+  }
+}
+
+uint64_t r[4] = {0x0, 0x0, 0x0, 0x0};
+
+void execute_call(int call)
+{
+  intptr_t res = 0;
+  switch (call) {
+  case 0:
+    *(uint32_t*)0x20000000 = 0x3f;
+    *(uint32_t*)0x20000004 = 8;
+    *(uint32_t*)0x20000008 = 0x1000;
+    *(uint32_t*)0x2000000c = 7;
+    syscall(SYS_sigsuspend, 0x20000000ul);
+    break;
+  case 1:
+    syscall(SYS_setgid, 0);
+    break;
+  case 2:
+    syscall(SYS_getgroups, 0ul, 0ul);
+    break;
+  case 3:
+    syscall(SYS_setegid, 0);
+    break;
+  case 4:
+    res = syscall(SYS_shmget, 0ul, 0x2000ul, 0x420ul, 0x20ffd000ul);
+    if (res != -1)
+      r[0] = res;
+    break;
+  case 5:
+    res = syscall(SYS_getpid);
+    if (res != -1)
+      r[1] = res;
+    break;
+  case 6:
+    *(uint32_t*)0x20000200 = -1;
+    *(uint32_t*)0x20000204 = 0;
+    *(uint32_t*)0x20000208 = -1;
+    *(uint32_t*)0x2000020c = 0;
+    *(uint16_t*)0x20000210 = 0xf965;
+    *(uint16_t*)0x20000212 = 0x2000;
+    *(uint32_t*)0x20000214 = 0;
+    *(uint64_t*)0x20000218 = 0x2d;
+    *(uint32_t*)0x20000220 = 0x1f;
+    *(uint64_t*)0x20000228 = 2;
+    *(uint64_t*)0x20000230 = 4;
+    *(uint64_t*)0x20000238 = 0;
+    *(uint32_t*)0x20000240 = r[1];
+    *(uint32_t*)0x20000244 = -1;
+    *(uint16_t*)0x20000248 = 7;
+    *(uint16_t*)0x2000024a = 0;
+    *(uint64_t*)0x20000250 = 0;
+    *(uint64_t*)0x20000258 = 0;
+    syscall(SYS_shmctl, r[0], 1ul, 0x20000200ul);
+    break;
+  case 7:
+    syscall(SYS_getgid);
+    break;
+  case 8:
+    syscall(SYS___semctl, 0, 0ul, 1ul, 0ul);
+    break;
+  case 9:
+    *(uint32_t*)0x20000300 = 4;
+    *(uint32_t*)0x20000304 = 0;
+    *(uint16_t*)0x20000308 = 7;
+    *(uint16_t*)0x2000030a = 6;
+    memcpy((void*)0x2000030c,
+           "\x26\xb9\x52\x60\x70\xe1\xb8\x97\x99\x4b\x39\xd3\xea\x42\xe7\xed",
+           16);
+    syscall(SYS_fhstat, 0x20000300ul, 0ul);
+    break;
+  case 10:
+    res = syscall(SYS_getgid);
+    if (res != -1)
+      r[2] = res;
+    break;
+  case 11:
+    *(uint32_t*)0x20000440 = 3;
+    *(uint32_t*)0x20000444 = 0;
+    *(uint32_t*)0x20000448 = r[1];
+    *(uint32_t*)0x2000044c = 0x81;
+    *(uint32_t*)0x20000450 = r[1];
+    memset((void*)0x20000454, 0, 60);
+    res = syscall(SYS_procctl, 0ul, r[1], 6ul, 0x20000440ul);
+    if (res != -1)
+      r[3] = *(uint32_t*)0x20000450;
+    break;
+  case 12:
+    *(uint32_t*)0x200004c0 = 0;
+    *(uint32_t*)0x200004c4 = 0;
+    *(uint32_t*)0x200004c8 = 0;
+    *(uint32_t*)0x200004cc = r[2];
+    *(uint16_t*)0x200004d0 = 0x100;
+    *(uint16_t*)0x200004d2 = 8;
+    *(uint32_t*)0x200004d4 = 0;
+    *(uint64_t*)0x200004d8 = 0x7ff;
+    *(uint64_t*)0x200004e0 = 0x7f;
+    *(uint64_t*)0x200004e8 = 0x81;
+    *(uint64_t*)0x200004f0 = 0xfff;
+    *(uint64_t*)0x200004f8 = 0x3a;
+    *(uint64_t*)0x20000500 = 0x100000000;
+    *(uint64_t*)0x20000508 = 9;
+    *(uint32_t*)0x20000510 = r[1];
+    *(uint32_t*)0x20000514 = r[3];
+    *(uint64_t*)0x20000518 = 0;
+    *(uint64_t*)0x20000520 = 0;
+    syscall(SYS_msgctl, -1, 1ul, 0x200004c0ul);
+    break;
+  case 13:
+    syscall(SYS_ioctl, -1, 0xc0f24425ul, 0ul);
+    break;
+  }
+}
+int main(void)
+{
+  syscall(SYS_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x1012ul, -1, 0ul);
+  for (procid = 0; procid < 4; procid++) {
+    if (fork() == 0) {
+      use_temporary_dir();
+      do_sandbox_none();
+    }
+  }
+  sleep(1000000);
+  return 0;
+}
+EOF
+mycc -o /tmp/syzkaller52 -Wall -Wextra -O0 /tmp/syzkaller52.c -l pthread ||
+    exit 1
+
+start=`date +%s`
+while [ $((`date +%s` - start)) -lt 120 ]; do
+	(cd /tmp; timeout 3m ./syzkaller52)
+done
+
+rm -rf /tmp/syzkaller52 /tmp/syzkaller52.c /tmp/syzkaller52.core \
+    /tmp/syzkaller.??????
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