[Linux Kernel Bugs] KASAN: slab-use-after-free Write in dvb_device_open and 6 other issues in dvb subsystem

[Jiaming Zhang]

Dear Linux kernel developers and maintainers,

We are writing to report 7 issues discovered in the dvb subsystem with
our generated syzkaller specifications. Below are the details of these
issues:

(1) KASAN: slab-use-after-free Write in dvb_device_open (reproducer: c, syz)
(2) KASAN: slab-use-after-free Read in dvb_frontend_release (reproducer: syz)
(3) possible deadlock in dvb_dvr_release (reproducer: c, syz)
(4) KASAN: slab-use-after-free Read in dvb_frontend_thread
(5) KFENCE: use-after-free read in dvb_frontend_release
(6) WARNING: still has locks held in _dmxdev_lock
(7) WARNING: bad unlock balance in _dmxdev_unlock

Here is our analysis:

## (1) KASAN: slab-use-after-free Write in dvb_device_open

The root cause is double put. In dvb_device_open(), the refcount is
decreased (via put) when the open operation fails [1]. However, in
dvb_frontend_open(), put will also be called in dvb_generic_release()
if dvb_frontend_start() failed. Such process can lead to double put
and use-after-free.

[1] https://elixir.bootlin.com/linux/v6.19-rc4/source/drivers/media/dvb-core/dvbdev.c#L113

## (2) KASAN: slab-use-after-free Read in dvb_frontend_release

The root cause is that in concurrent scenarios, the kernel attempts to
access dvbdev->users after dvbdev has already been freed [2].

[2] https://elixir.bootlin.com/linux/v6.19-rc4/source/drivers/media/dvb-core/dvb_frontend.c#L2916

## (3) possible deadlock in dvb_dvr_release

The root cause is lock imbalance. Call chain is as follows:

    dvb_vb2_dqbuf() ->
    vb2_core_dqbuf() ->
    __vb2_get_done_vb() ->
    __vb2_wait_for_done_vb() ->
    _dmxdev_lock() (call_void_qop(q, wait_finish, q)) ->
    mutex_lock()

ctx->mutex is locked during this process, but if the return value of
vb2_core_dqbuf() is not zero, ctx->mutex will not be unlocked [3].
When the task exits and calls dvb_dvr_release(), the function attempts
to acquire dmxdev->lock, lockdep detects that ctx->mutex is still
held, violating the locking order and reporting possible deadlock.

[3] https://elixir.bootlin.com/linux/v6.19-rc4/source/drivers/media/dvb-core/dvb_vb2.c#L415-L419

A potentail solution is to protect vb2_core_dqbuf() with mutex, e.g.

```
int dvb_vb2_dqbuf(struct dvb_vb2_ctx *ctx, struct dmx_buffer *b)
{
    unsigned long flags;
    int ret;

+   mutex_lock(&ctx->mutex);
    ret = vb2_core_dqbuf(&ctx->vb_q, &b->index, b, ctx->nonblocking);
+   mutex_unlock(&ctx->mutex);
    if (ret) ...
}
```

If this solution is acceptable, we would be happy to submit a patch :)

## Other issues

Unfortunately we do not have reproducers for other issues currently.
We have attached kernel console output to help with analysis and offer
our preliminary findings:

(4) KASAN: slab-use-after-free Read in dvb_frontend_thread: in
concurrent scenarios, kernel accesses fepriv->wait_queue after dvbdev
is freed [4]. Would adding a refcount for dvbdec to fix this?

(5) KFENCE: use-after-free read in dvb_frontend_release: similar to (2).

(6) WARNING: still has locks held in _dmxdev_lock: it seems a branch
in dvb_dvr_do_ioctl() might be acquiring a lock but failing to release
it?

(7) WARNING: bad unlock balance in _dmxdev_unlock: in call chain like
dvb_dvr_do_ioctl() -> dvb_vb2_dqbuf(), kernel misjudge lock state and
attempt to unlock an already unlocked lock?

[4] https://elixir.bootlin.com/linux/v6.19-rc4/source/drivers/media/dvb-core/dvb_frontend.c#L682-L685

You can refer to [5] to reproduce issues using syz programs. We also
provide our generated specs to help with running of syz program.

[5] https://github.com/google/syzkaller/blob/master/docs/reproducing_crashes.md#using-a-syz-reproducer

Please let me know if any further information is required.

Best Regards,
Jiaming Zhang
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE 

#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

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 bool write_file(const char* file, const char* what, ...)
{
	char buf[1024];
	va_list args;
	va_start(args, what);
	vsnprintf(buf, sizeof(buf), what, args);
	va_end(args);
	buf[sizeof(buf) - 1] = 0;
	int len = strlen(buf);
	int fd = open(file, O_WRONLY | O_CLOEXEC);
	if (fd == -1)
		return false;
	if (write(fd, buf, len) != len) {
		int err = errno;
		close(fd);
		errno = err;
		return false;
	}
	close(fd);
	return true;
}

static long syz_open_dev(volatile long a0, volatile long a1, volatile long a2)
{
	if (a0 == 0xc || a0 == 0xb) {
		char buf[128];
		sprintf(buf, "/dev/%s/%d:%d", a0 == 0xc ? "char" : "block", (uint8_t)a1, (uint8_t)a2);
		return open(buf, O_RDWR, 0);
	} else {
		unsigned long nb = a1;
		char buf[1024];
		char* hash;
		strncpy(buf, (char*)a0, sizeof(buf) - 1);
		buf[sizeof(buf) - 1] = 0;
		while ((hash = strchr(buf, '#'))) {
			*hash = '0' + (char)(nb % 10);
			nb /= 10;
		}
		return open(buf, a2 & ~O_CREAT, 0);
	}
}

static void kill_and_wait(int pid, int* status)
{
	kill(-pid, SIGKILL);
	kill(pid, SIGKILL);
	for (int i = 0; i < 100; i++) {
		if (waitpid(-1, status, WNOHANG | __WALL) == pid)
			return;
		usleep(1000);
	}
	DIR* dir = opendir("/sys/fs/fuse/connections");
	if (dir) {
		for (;;) {
			struct dirent* ent = readdir(dir);
			if (!ent)
				break;
			if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0)
				continue;
			char abort[300];
			snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort", ent->d_name);
			int fd = open(abort, O_WRONLY);
			if (fd == -1) {
				continue;
			}
			if (write(fd, abort, 1) < 0) {
			}
			close(fd);
		}
		closedir(dir);
	} else {
	}
	while (waitpid(-1, status, __WALL) != pid) {
	}
}

static void setup_test()
{
	prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
	setpgrp();
	write_file("/proc/self/oom_score_adj", "1000");
}

static void execute_one(void);

#define WAIT_FLAGS __WALL

static void loop(void)
{
	int iter = 0;
	for (;; iter++) {
		int pid = fork();
		if (pid < 0)
	exit(1);
		if (pid == 0) {
			setup_test();
			execute_one();
			exit(0);
		}
		int status = 0;
		uint64_t start = current_time_ms();
		for (;;) {
			sleep_ms(10);
			if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid)
				break;
			if (current_time_ms() - start < 5000)
				continue;
			kill_and_wait(pid, &status);
			break;
		}
	}
}

uint64_t r[1] = {0xffffffffffffffff};

void execute_one(void)
{
		intptr_t res = 0;
	if (write(1, "executing program\n", sizeof("executing program\n") - 1)) {}
//  syz_open_dev$dvb_dvr arguments: [
//    dev: ptr[in, buffer] {
//      buffer: {2f 64 65 76 2f 64 76 62 2f 61 64 61 70 74 65 72 23 2f 64 76 72 23 00} (length 0x17)
//    }
//    id: intptr = 0x0 (8 bytes)
//    flags: open_flags = 0x121082 (8 bytes)
//  ]
//  returns fd_dvb_dvr
memcpy((void*)0x200000000000, "/dev/dvb/adapter#/dvr#\000", 23);
	res = -1;
res = syz_open_dev(/*dev=*/0x200000000000, /*id=*/0, /*flags=O_SYNC|O_NOFOLLOW|O_EXCL|O_RDWR*/0x121082);
	if (res != -1)
		r[0] = res;
//  ioctl$DVB_DVR_DMX_REQBUFS arguments: [
//    fd: fd_dvb_dvr (resource)
//    cmd: const = 0xc0086f3c (4 bytes)
//    arg: ptr[inout, dmx_requestbuffers] {
//      dmx_requestbuffers {
//        count: int32 = 0x9 (4 bytes)
//        size: int32 = 0x2 (4 bytes)
//      }
//    }
//  ]
*(uint32_t*)0x200000000040 = 9;
*(uint32_t*)0x200000000044 = 2;
	syscall(__NR_ioctl, /*fd=*/r[0], /*cmd=*/0xc0086f3c, /*arg=*/0x200000000040ul);
//  ioctl$DVB_DVR_DMX_QBUF arguments: [
//    fd: fd_dvb_dvr (resource)
//    cmd: const = 0xc0186f3f (4 bytes)
//    arg: ptr[inout, dmx_buffer] {
//      dmx_buffer {
//        index: int32 = 0x8 (4 bytes)
//        bytesused: int32 = 0x6 (4 bytes)
//        flags: int32 = 0x9 (4 bytes)
//      }
//    }
//  ]
*(uint32_t*)0x200000000280 = 8;
*(uint32_t*)0x200000000284 = 6;
*(uint32_t*)0x200000000288 = 9;
	syscall(__NR_ioctl, /*fd=*/r[0], /*cmd=*/0xc0186f3f, /*arg=*/0x200000000280ul);
//  ioctl$DVB_DVR_DMX_DQBUF arguments: [
//    fd: fd_dvb_dvr (resource)
//    cmd: const = 0xc0186f40 (4 bytes)
//    arg: ptr[inout, dmx_buffer] {
//      dmx_buffer {
//        index: int32 = 0xfffff027 (4 bytes)
//        bytesused: int32 = 0xa1 (4 bytes)
//        flags: int32 = 0x7f (4 bytes)
//      }
//    }
//  ]
*(uint32_t*)0x2000000003c0 = 0xfffff027;
*(uint32_t*)0x2000000003c4 = 0xa1;
*(uint32_t*)0x2000000003c8 = 0x7f;
	syscall(__NR_ioctl, /*fd=*/r[0], /*cmd=*/0xc0186f40, /*arg=*/0x2000000003c0ul);

}
int main(void)
{
		syscall(__NR_mmap, /*addr=*/0x1ffffffff000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul);
	syscall(__NR_mmap, /*addr=*/0x200000000000ul, /*len=*/0x1000000ul, /*prot=PROT_WRITE|PROT_READ|PROT_EXEC*/7ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul);
	syscall(__NR_mmap, /*addr=*/0x200001000000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul);
	const char* reason;
	(void)reason;
			loop();
	return 0;
}

Attachment: .config
Description: XML document

Attachment: [deadlock-dvb_dvr_release] report
Description: Binary data

Attachment: [deadlock-dvb_dvr_release] repro.syz
Description: Binary data

Attachment: [deadlock-dvb_dvr_release] kernel.log
Description: Binary data

Attachment: [kasan-suaf-read-dvb_frontend_release] report
Description: Binary data

Attachment: [kasan-suaf-read-dvb_frontend_release] kernel.log
Description: Binary data

Attachment: [kasan-suaf-read-dvb_frontend_thread] kernel.log
Description: Binary data

Attachment: [kasan-suaf-read-dvb_frontend_thread] report
Description: Binary data

Attachment: [kasan-suaf-write-dvb_device_open] kernel.log
Description: Binary data

Attachment: [kasan-suaf-write-dvb_device_open] report
Description: Binary data

// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE 

#include <arpa/inet.h>
#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <net/if.h>
#include <netinet/in.h>
#include <pthread.h>
#include <sched.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/swap.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

#include <linux/capability.h>
#include <linux/falloc.h>
#include <linux/futex.h>
#include <linux/genetlink.h>
#include <linux/if_addr.h>
#include <linux/if_ether.h>
#include <linux/if_link.h>
#include <linux/in6.h>
#include <linux/neighbour.h>
#include <linux/net.h>
#include <linux/netlink.h>
#include <linux/nl80211.h>
#include <linux/rfkill.h>
#include <linux/rtnetlink.h>
#include <linux/veth.h>

static unsigned long long procid;

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 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 {
	int state;
} event_t;

static void event_init(event_t* ev)
{
	ev->state = 0;
}

static void event_reset(event_t* ev)
{
	ev->state = 0;
}

static void event_set(event_t* ev)
{
	if (ev->state)
	exit(1);
	__atomic_store_n(&ev->state, 1, __ATOMIC_RELEASE);
	syscall(SYS_futex, &ev->state, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1000000);
}

static void event_wait(event_t* ev)
{
	while (!__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE))
		syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, 0);
}

static int event_isset(event_t* ev)
{
	return __atomic_load_n(&ev->state, __ATOMIC_ACQUIRE);
}

static int event_timedwait(event_t* ev, uint64_t timeout)
{
	uint64_t start = current_time_ms();
	uint64_t now = start;
	for (;;) {
		uint64_t remain = timeout - (now - start);
		struct timespec ts;
		ts.tv_sec = remain / 1000;
		ts.tv_nsec = (remain % 1000) * 1000 * 1000;
		syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, &ts);
		if (__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE))
			return 1;
		now = current_time_ms();
		if (now - start > timeout)
			return 0;
	}
}

static bool write_file(const char* file, const char* what, ...)
{
	char buf[1024];
	va_list args;
	va_start(args, what);
	vsnprintf(buf, sizeof(buf), what, args);
	va_end(args);
	buf[sizeof(buf) - 1] = 0;
	int len = strlen(buf);
	int fd = open(file, O_WRONLY | O_CLOEXEC);
	if (fd == -1)
		return false;
	if (write(fd, buf, len) != len) {
		int err = errno;
		close(fd);
		errno = err;
		return false;
	}
	close(fd);
	return true;
}

struct nlmsg {
	char* pos;
	int nesting;
	struct nlattr* nested[8];
	char buf[4096];
};

static void netlink_init(struct nlmsg* nlmsg, int typ, int flags,
			 const void* data, int size)
{
	memset(nlmsg, 0, sizeof(*nlmsg));
	struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg->buf;
	hdr->nlmsg_type = typ;
	hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | flags;
	memcpy(hdr + 1, data, size);
	nlmsg->pos = (char*)(hdr + 1) + NLMSG_ALIGN(size);
}

static void netlink_attr(struct nlmsg* nlmsg, int typ,
			 const void* data, int size)
{
	struct nlattr* attr = (struct nlattr*)nlmsg->pos;
	attr->nla_len = sizeof(*attr) + size;
	attr->nla_type = typ;
	if (size > 0)
		memcpy(attr + 1, data, size);
	nlmsg->pos += NLMSG_ALIGN(attr->nla_len);
}

static int netlink_send_ext(struct nlmsg* nlmsg, int sock,
			    uint16_t reply_type, int* reply_len, bool dofail)
{
	if (nlmsg->pos > nlmsg->buf + sizeof(nlmsg->buf) || nlmsg->nesting)
	exit(1);
	struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg->buf;
	hdr->nlmsg_len = nlmsg->pos - nlmsg->buf;
	struct sockaddr_nl addr;
	memset(&addr, 0, sizeof(addr));
	addr.nl_family = AF_NETLINK;
	ssize_t n = sendto(sock, nlmsg->buf, hdr->nlmsg_len, 0, (struct sockaddr*)&addr, sizeof(addr));
	if (n != (ssize_t)hdr->nlmsg_len) {
		if (dofail)
	exit(1);
		return -1;
	}
	n = recv(sock, nlmsg->buf, sizeof(nlmsg->buf), 0);
	if (reply_len)
		*reply_len = 0;
	if (n < 0) {
		if (dofail)
	exit(1);
		return -1;
	}
	if (n < (ssize_t)sizeof(struct nlmsghdr)) {
		errno = EINVAL;
		if (dofail)
	exit(1);
		return -1;
	}
	if (hdr->nlmsg_type == NLMSG_DONE)
		return 0;
	if (reply_len && hdr->nlmsg_type == reply_type) {
		*reply_len = n;
		return 0;
	}
	if (n < (ssize_t)(sizeof(struct nlmsghdr) + sizeof(struct nlmsgerr))) {
		errno = EINVAL;
		if (dofail)
	exit(1);
		return -1;
	}
	if (hdr->nlmsg_type != NLMSG_ERROR) {
		errno = EINVAL;
		if (dofail)
	exit(1);
		return -1;
	}
	errno = -((struct nlmsgerr*)(hdr + 1))->error;
	return -errno;
}

static int netlink_send(struct nlmsg* nlmsg, int sock)
{
	return netlink_send_ext(nlmsg, sock, 0, NULL, true);
}

static int netlink_query_family_id(struct nlmsg* nlmsg, int sock, const char* family_name, bool dofail)
{
	struct genlmsghdr genlhdr;
	memset(&genlhdr, 0, sizeof(genlhdr));
	genlhdr.cmd = CTRL_CMD_GETFAMILY;
	netlink_init(nlmsg, GENL_ID_CTRL, 0, &genlhdr, sizeof(genlhdr));
	netlink_attr(nlmsg, CTRL_ATTR_FAMILY_NAME, family_name, strnlen(family_name, GENL_NAMSIZ - 1) + 1);
	int n = 0;
	int err = netlink_send_ext(nlmsg, sock, GENL_ID_CTRL, &n, dofail);
	if (err < 0) {
		return -1;
	}
	uint16_t id = 0;
	struct nlattr* attr = (struct nlattr*)(nlmsg->buf + NLMSG_HDRLEN + NLMSG_ALIGN(sizeof(genlhdr)));
	for (; (char*)attr < nlmsg->buf + n; attr = (struct nlattr*)((char*)attr + NLMSG_ALIGN(attr->nla_len))) {
		if (attr->nla_type == CTRL_ATTR_FAMILY_ID) {
			id = *(uint16_t*)(attr + 1);
			break;
		}
	}
	if (!id) {
		errno = EINVAL;
		return -1;
	}
	recv(sock, nlmsg->buf, sizeof(nlmsg->buf), 0);
	return id;
}

static struct nlmsg nlmsg;

#define WIFI_INITIAL_DEVICE_COUNT 2
#define WIFI_MAC_BASE { 0x08, 0x02, 0x11, 0x00, 0x00, 0x00}
#define WIFI_IBSS_BSSID { 0x50, 0x50, 0x50, 0x50, 0x50, 0x50}
#define WIFI_IBSS_SSID { 0x10, 0x10, 0x10, 0x10, 0x10, 0x10}
#define WIFI_DEFAULT_FREQUENCY 2412
#define WIFI_DEFAULT_SIGNAL 0
#define WIFI_DEFAULT_RX_RATE 1
#define HWSIM_CMD_REGISTER 1
#define HWSIM_CMD_FRAME 2
#define HWSIM_CMD_NEW_RADIO 4
#define HWSIM_ATTR_SUPPORT_P2P_DEVICE 14
#define HWSIM_ATTR_PERM_ADDR 22

#define IF_OPER_UP 6
struct join_ibss_props {
	int wiphy_freq;
	bool wiphy_freq_fixed;
	uint8_t* mac;
	uint8_t* ssid;
	int ssid_len;
};

static int set_interface_state(const char* interface_name, int on)
{
	struct ifreq ifr;
	int sock = socket(AF_INET, SOCK_DGRAM, 0);
	if (sock < 0) {
		return -1;
	}
	memset(&ifr, 0, sizeof(ifr));
	strcpy(ifr.ifr_name, interface_name);
	int ret = ioctl(sock, SIOCGIFFLAGS, &ifr);
	if (ret < 0) {
		close(sock);
		return -1;
	}
	if (on)
		ifr.ifr_flags |= IFF_UP;
	else
		ifr.ifr_flags &= ~IFF_UP;
	ret = ioctl(sock, SIOCSIFFLAGS, &ifr);
	close(sock);
	if (ret < 0) {
		return -1;
	}
	return 0;
}

static int nl80211_set_interface(struct nlmsg* nlmsg, int sock, int nl80211_family, uint32_t ifindex,
				 uint32_t iftype, bool dofail)
{
	struct genlmsghdr genlhdr;
	memset(&genlhdr, 0, sizeof(genlhdr));
	genlhdr.cmd = NL80211_CMD_SET_INTERFACE;
	netlink_init(nlmsg, nl80211_family, 0, &genlhdr, sizeof(genlhdr));
	netlink_attr(nlmsg, NL80211_ATTR_IFINDEX, &ifindex, sizeof(ifindex));
	netlink_attr(nlmsg, NL80211_ATTR_IFTYPE, &iftype, sizeof(iftype));
	int err = netlink_send_ext(nlmsg, sock, 0, NULL, dofail);
	if (err < 0) {
	}
	return err;
}

static int nl80211_join_ibss(struct nlmsg* nlmsg, int sock, int nl80211_family, uint32_t ifindex,
			     struct join_ibss_props* props, bool dofail)
{
	struct genlmsghdr genlhdr;
	memset(&genlhdr, 0, sizeof(genlhdr));
	genlhdr.cmd = NL80211_CMD_JOIN_IBSS;
	netlink_init(nlmsg, nl80211_family, 0, &genlhdr, sizeof(genlhdr));
	netlink_attr(nlmsg, NL80211_ATTR_IFINDEX, &ifindex, sizeof(ifindex));
	netlink_attr(nlmsg, NL80211_ATTR_SSID, props->ssid, props->ssid_len);
	netlink_attr(nlmsg, NL80211_ATTR_WIPHY_FREQ, &(props->wiphy_freq), sizeof(props->wiphy_freq));
	if (props->mac)
		netlink_attr(nlmsg, NL80211_ATTR_MAC, props->mac, ETH_ALEN);
	if (props->wiphy_freq_fixed)
		netlink_attr(nlmsg, NL80211_ATTR_FREQ_FIXED, NULL, 0);
	int err = netlink_send_ext(nlmsg, sock, 0, NULL, dofail);
	if (err < 0) {
	}
	return err;
}

static int get_ifla_operstate(struct nlmsg* nlmsg, int ifindex, bool dofail)
{
	struct ifinfomsg info;
	memset(&info, 0, sizeof(info));
	info.ifi_family = AF_UNSPEC;
	info.ifi_index = ifindex;
	int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
	if (sock == -1) {
		return -1;
	}
	netlink_init(nlmsg, RTM_GETLINK, 0, &info, sizeof(info));
	int n;
	int err = netlink_send_ext(nlmsg, sock, RTM_NEWLINK, &n, dofail);
	close(sock);
	if (err) {
		return -1;
	}
	struct rtattr* attr = IFLA_RTA(NLMSG_DATA(nlmsg->buf));
	for (; RTA_OK(attr, n); attr = RTA_NEXT(attr, n)) {
		if (attr->rta_type == IFLA_OPERSTATE)
			return *((int32_t*)RTA_DATA(attr));
	}
	return -1;
}

static int await_ifla_operstate(struct nlmsg* nlmsg, char* interface, int operstate, bool dofail)
{
	int ifindex = if_nametoindex(interface);
	while (true) {
		usleep(1000);
		int ret = get_ifla_operstate(nlmsg, ifindex, dofail);
		if (ret < 0)
			return ret;
		if (ret == operstate)
			return 0;
	}
	return 0;
}

static int nl80211_setup_ibss_interface(struct nlmsg* nlmsg, int sock, int nl80211_family_id, char* interface,
					struct join_ibss_props* ibss_props, bool dofail)
{
	int ifindex = if_nametoindex(interface);
	if (ifindex == 0) {
		return -1;
	}
	int ret = nl80211_set_interface(nlmsg, sock, nl80211_family_id, ifindex, NL80211_IFTYPE_ADHOC, dofail);
	if (ret < 0) {
		return -1;
	}
	ret = set_interface_state(interface, 1);
	if (ret < 0) {
		return -1;
	}
	ret = nl80211_join_ibss(nlmsg, sock, nl80211_family_id, ifindex, ibss_props, dofail);
	if (ret < 0) {
		return -1;
	}
	return 0;
}

static int hwsim80211_create_device(struct nlmsg* nlmsg, int sock, int hwsim_family, uint8_t mac_addr[ETH_ALEN])
{
	struct genlmsghdr genlhdr;
	memset(&genlhdr, 0, sizeof(genlhdr));
	genlhdr.cmd = HWSIM_CMD_NEW_RADIO;
	netlink_init(nlmsg, hwsim_family, 0, &genlhdr, sizeof(genlhdr));
	netlink_attr(nlmsg, HWSIM_ATTR_SUPPORT_P2P_DEVICE, NULL, 0);
	netlink_attr(nlmsg, HWSIM_ATTR_PERM_ADDR, mac_addr, ETH_ALEN);
	int err = netlink_send(nlmsg, sock);
	if (err < 0) {
	}
	return err;
}

static void initialize_wifi_devices(void)
{
	int rfkill = open("/dev/rfkill", O_RDWR);
	if (rfkill == -1)
	exit(1);
	struct rfkill_event event = {0};
	event.type = RFKILL_TYPE_ALL;
	event.op = RFKILL_OP_CHANGE_ALL;
	if (write(rfkill, &event, sizeof(event)) != (ssize_t)(sizeof(event)))
	exit(1);
	close(rfkill);
	uint8_t mac_addr[6] = WIFI_MAC_BASE;
	int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC);
	if (sock < 0)
	exit(1);
	int hwsim_family_id = netlink_query_family_id(&nlmsg, sock, "MAC80211_HWSIM", true);
	int nl80211_family_id = netlink_query_family_id(&nlmsg, sock, "nl80211", true);
	if (hwsim_family_id < 0 || nl80211_family_id < 0)
	exit(1);
	uint8_t ssid[] = WIFI_IBSS_SSID;
	uint8_t bssid[] = WIFI_IBSS_BSSID;
	struct join_ibss_props ibss_props = {
	    .wiphy_freq = WIFI_DEFAULT_FREQUENCY, .wiphy_freq_fixed = true, .mac = bssid, .ssid = ssid, .ssid_len = sizeof(ssid)};
	for (int device_id = 0; device_id < WIFI_INITIAL_DEVICE_COUNT; device_id++) {
		mac_addr[5] = device_id;
		int ret = hwsim80211_create_device(&nlmsg, sock, hwsim_family_id, mac_addr);
		if (ret < 0)
	exit(1);
		char interface[6] = "wlan0";
		interface[4] += device_id;
		if (nl80211_setup_ibss_interface(&nlmsg, sock, nl80211_family_id, interface, &ibss_props, true) < 0)
	exit(1);
	}
	for (int device_id = 0; device_id < WIFI_INITIAL_DEVICE_COUNT; device_id++) {
		char interface[6] = "wlan0";
		interface[4] += device_id;
		int ret = await_ifla_operstate(&nlmsg, interface, IF_OPER_UP, true);
		if (ret < 0)
	exit(1);
	}
	close(sock);
}

static int runcmdline(char* cmdline)
{
	int ret = system(cmdline);
	if (ret) {
	}
	return ret;
}

#define MAX_FDS 30

static long syz_open_dev(volatile long a0, volatile long a1, volatile long a2)
{
	if (a0 == 0xc || a0 == 0xb) {
		char buf[128];
		sprintf(buf, "/dev/%s/%d:%d", a0 == 0xc ? "char" : "block", (uint8_t)a1, (uint8_t)a2);
		return open(buf, O_RDWR, 0);
	} else {
		unsigned long nb = a1;
		char buf[1024];
		char* hash;
		strncpy(buf, (char*)a0, sizeof(buf) - 1);
		buf[sizeof(buf) - 1] = 0;
		while ((hash = strchr(buf, '#'))) {
			*hash = '0' + (char)(nb % 10);
			nb /= 10;
		}
		return open(buf, a2 & ~O_CREAT, 0);
	}
}

static void setup_gadgetfs();
static void setup_binderfs();
static void setup_fusectl();
static void sandbox_common_mount_tmpfs(void)
{
	write_file("/proc/sys/fs/mount-max", "100000");
	if (mkdir("./syz-tmp", 0777))
	exit(1);
	if (mount("", "./syz-tmp", "tmpfs", 0, NULL))
	exit(1);
	if (mkdir("./syz-tmp/newroot", 0777))
	exit(1);
	if (mkdir("./syz-tmp/newroot/dev", 0700))
	exit(1);
	unsigned bind_mount_flags = MS_BIND | MS_REC | MS_PRIVATE;
	if (mount("/dev", "./syz-tmp/newroot/dev", NULL, bind_mount_flags, NULL))
	exit(1);
	if (mkdir("./syz-tmp/newroot/proc", 0700))
	exit(1);
	if (mount("syz-proc", "./syz-tmp/newroot/proc", "proc", 0, NULL))
	exit(1);
	if (mkdir("./syz-tmp/newroot/selinux", 0700))
	exit(1);
	const char* selinux_path = "./syz-tmp/newroot/selinux";
	if (mount("/selinux", selinux_path, NULL, bind_mount_flags, NULL)) {
		if (errno != ENOENT)
	exit(1);
		if (mount("/sys/fs/selinux", selinux_path, NULL, bind_mount_flags, NULL) && errno != ENOENT)
	exit(1);
	}
	if (mkdir("./syz-tmp/newroot/sys", 0700))
	exit(1);
	if (mount("/sys", "./syz-tmp/newroot/sys", 0, bind_mount_flags, NULL))
	exit(1);
	if (mount("/sys/kernel/debug", "./syz-tmp/newroot/sys/kernel/debug", NULL, bind_mount_flags, NULL) && errno != ENOENT)
	exit(1);
	if (mount("/sys/fs/smackfs", "./syz-tmp/newroot/sys/fs/smackfs", NULL, bind_mount_flags, NULL) && errno != ENOENT)
	exit(1);
	if (mount("/proc/sys/fs/binfmt_misc", "./syz-tmp/newroot/proc/sys/fs/binfmt_misc", NULL, bind_mount_flags, NULL) && errno != ENOENT)
	exit(1);
	if (mkdir("./syz-tmp/newroot/syz-inputs", 0700))
	exit(1);
	if (mount("/syz-inputs", "./syz-tmp/newroot/syz-inputs", NULL, bind_mount_flags | MS_RDONLY, NULL) && errno != ENOENT)
	exit(1);
	if (mkdir("./syz-tmp/pivot", 0777))
	exit(1);
	if (syscall(SYS_pivot_root, "./syz-tmp", "./syz-tmp/pivot")) {
		if (chdir("./syz-tmp"))
	exit(1);
	} else {
		if (chdir("/"))
	exit(1);
		if (umount2("./pivot", MNT_DETACH))
	exit(1);
	}
	if (chroot("./newroot"))
	exit(1);
	if (chdir("/"))
	exit(1);
	setup_gadgetfs();
	setup_binderfs();
	setup_fusectl();
}

static void setup_gadgetfs()
{
	if (mkdir("/dev/gadgetfs", 0777)) {
	}
	if (mount("gadgetfs", "/dev/gadgetfs", "gadgetfs", 0, NULL)) {
	}
}

static void setup_fusectl()
{
	if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) {
	}
}

static void setup_binderfs()
{
	if (mkdir("/dev/binderfs", 0777)) {
	}
	if (mount("binder", "/dev/binderfs", "binder", 0, NULL)) {
	}
}

static void loop();

static void sandbox_common()
{
	prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
	if (getppid() == 1)
	exit(1);
	struct rlimit rlim;
	rlim.rlim_cur = rlim.rlim_max = (200 << 20);
	setrlimit(RLIMIT_AS, &rlim);
	rlim.rlim_cur = rlim.rlim_max = 32 << 20;
	setrlimit(RLIMIT_MEMLOCK, &rlim);
	rlim.rlim_cur = rlim.rlim_max = 136 << 20;
	setrlimit(RLIMIT_FSIZE, &rlim);
	rlim.rlim_cur = rlim.rlim_max = 1 << 20;
	setrlimit(RLIMIT_STACK, &rlim);
	rlim.rlim_cur = rlim.rlim_max = 128 << 20;
	setrlimit(RLIMIT_CORE, &rlim);
	rlim.rlim_cur = rlim.rlim_max = 256;
	setrlimit(RLIMIT_NOFILE, &rlim);
	if (unshare(CLONE_NEWNS)) {
	}
	if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL)) {
	}
	if (unshare(CLONE_NEWIPC)) {
	}
	if (unshare(0x02000000)) {
	}
	if (unshare(CLONE_NEWUTS)) {
	}
	if (unshare(CLONE_SYSVSEM)) {
	}
	typedef struct {
		const char* name;
		const char* value;
	} sysctl_t;
	static const sysctl_t sysctls[] = {
	    {"/proc/sys/kernel/shmmax", "16777216"},
	    {"/proc/sys/kernel/shmall", "536870912"},
	    {"/proc/sys/kernel/shmmni", "1024"},
	    {"/proc/sys/kernel/msgmax", "8192"},
	    {"/proc/sys/kernel/msgmni", "1024"},
	    {"/proc/sys/kernel/msgmnb", "1024"},
	    {"/proc/sys/kernel/sem", "1024 1048576 500 1024"},
	};
	unsigned i;
	for (i = 0; i < sizeof(sysctls) / sizeof(sysctls[0]); i++)
		write_file(sysctls[i].name, sysctls[i].value);
}

static int wait_for_loop(int pid)
{
	if (pid < 0)
	exit(1);
	int status = 0;
	while (waitpid(-1, &status, __WALL) != pid) {
	}
	return WEXITSTATUS(status);
}

static void drop_caps(void)
{
	struct __user_cap_header_struct cap_hdr = {};
	struct __user_cap_data_struct cap_data[2] = {};
	cap_hdr.version = _LINUX_CAPABILITY_VERSION_3;
	cap_hdr.pid = getpid();
	if (syscall(SYS_capget, &cap_hdr, &cap_data))
	exit(1);
	const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE);
	cap_data[0].effective &= ~drop;
	cap_data[0].permitted &= ~drop;
	cap_data[0].inheritable &= ~drop;
	if (syscall(SYS_capset, &cap_hdr, &cap_data))
	exit(1);
}

static int do_sandbox_none(void)
{
	if (unshare(CLONE_NEWPID)) {
	}
	int pid = fork();
	if (pid != 0)
		return wait_for_loop(pid);
	sandbox_common();
	drop_caps();
	if (unshare(CLONE_NEWNET)) {
	}
	write_file("/proc/sys/net/ipv4/ping_group_range", "0 65535");
	initialize_wifi_devices();
	sandbox_common_mount_tmpfs();
	loop();
	exit(1);
}

#define FS_IOC_SETFLAGS _IOW('f', 2, long)
static void remove_dir(const char* dir)
{
	int iter = 0;
	DIR* dp = 0;
	const int umount_flags = MNT_FORCE | UMOUNT_NOFOLLOW;

retry:
		while (umount2(dir, umount_flags) == 0) {
		}
	dp = opendir(dir);
	if (dp == NULL) {
		if (errno == EMFILE) {
	exit(1);
		}
	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);
			while (umount2(filename, umount_flags) == 0) {
			}
		struct stat st;
		if (lstat(filename, &st))
	exit(1);
		if (S_ISDIR(st.st_mode)) {
			remove_dir(filename);
			continue;
		}
		int i;
		for (i = 0;; i++) {
			if (unlink(filename) == 0)
				break;
			if (errno == EPERM) {
				int fd = open(filename, O_RDONLY);
				if (fd != -1) {
					long flags = 0;
					if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0) {
					}
					close(fd);
					continue;
				}
			}
			if (errno == EROFS) {
				break;
			}
			if (errno != EBUSY || i > 100)
	exit(1);
				if (umount2(filename, umount_flags))
	exit(1);
		}
	}
	closedir(dp);
	for (int i = 0;; i++) {
		if (rmdir(dir) == 0)
			break;
		if (i < 100) {
			if (errno == EPERM) {
				int fd = open(dir, O_RDONLY);
				if (fd != -1) {
					long flags = 0;
					if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0) {
					}
					close(fd);
					continue;
				}
			}
			if (errno == EROFS) {
				break;
			}
			if (errno == EBUSY) {
					if (umount2(dir, umount_flags))
	exit(1);
				continue;
			}
			if (errno == ENOTEMPTY) {
				if (iter < 100) {
					iter++;
					goto retry;
				}
			}
		}
	exit(1);
	}
}

static void kill_and_wait(int pid, int* status)
{
	kill(-pid, SIGKILL);
	kill(pid, SIGKILL);
	for (int i = 0; i < 100; i++) {
		if (waitpid(-1, status, WNOHANG | __WALL) == pid)
			return;
		usleep(1000);
	}
	DIR* dir = opendir("/sys/fs/fuse/connections");
	if (dir) {
		for (;;) {
			struct dirent* ent = readdir(dir);
			if (!ent)
				break;
			if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0)
				continue;
			char abort[300];
			snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort", ent->d_name);
			int fd = open(abort, O_WRONLY);
			if (fd == -1) {
				continue;
			}
			if (write(fd, abort, 1) < 0) {
			}
			close(fd);
		}
		closedir(dir);
	} else {
	}
	while (waitpid(-1, status, __WALL) != pid) {
	}
}

static void setup_test()
{
	prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
	setpgrp();
	write_file("/proc/self/oom_score_adj", "1000");
	if (symlink("/dev/binderfs", "./binderfs")) {
	}
}

static void close_fds()
{
	for (int fd = 3; fd < MAX_FDS; fd++)
		close(fd);
}

#define SWAP_FILE "./swap-file"
#define SWAP_FILE_SIZE (128 * 1000 * 1000)

static const char* setup_swap()
{
	swapoff(SWAP_FILE);
	unlink(SWAP_FILE);
	int fd = open(SWAP_FILE, O_CREAT | O_WRONLY | O_CLOEXEC, 0600);
	if (fd == -1)
		return "swap file open failed";
	fallocate(fd, FALLOC_FL_ZERO_RANGE, 0, SWAP_FILE_SIZE);
	close(fd);
	char cmdline[64];
	sprintf(cmdline, "mkswap %s", SWAP_FILE);
	if (runcmdline(cmdline))
		return "mkswap failed";
	if (swapon(SWAP_FILE, SWAP_FLAG_PREFER) == 1)
		return "swapon failed";
	return NULL;
}

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)
{
	if (write(1, "executing program\n", sizeof("executing program\n") - 1)) {
	}
	int i, call, thread;
	for (call = 0; call < 4; 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);
	close_fds();
}

static void execute_one(void);

#define WAIT_FLAGS __WALL

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);
			setup_test();
			execute_one();
			exit(0);
		}
		int status = 0;
		uint64_t start = current_time_ms();
		for (;;) {
			sleep_ms(10);
			if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid)
				break;
			if (current_time_ms() - start < 5000)
				continue;
			kill_and_wait(pid, &status);
			break;
		}
		remove_dir(cwdbuf);
	}
}

void execute_call(int call)
{
		switch (call) {
	case 0:
//  syz_open_dev$dvb_dvr arguments: [
//    dev: ptr[in, buffer] {
//      buffer: {2f 64 65 76 2f 64 76 62 2f 61 64 61 70 74 65 72 23 2f 64 76 72 23 00} (length 0x17)
//    }
//    id: intptr = 0x0 (8 bytes)
//    flags: open_flags = 0x100 (8 bytes)
//  ]
//  returns fd_dvb_dvr
memcpy((void*)0x200000000440, "/dev/dvb/adapter#/dvr#\000", 23);
syz_open_dev(/*dev=*/0x200000000440, /*id=*/0, /*flags=O_NOCTTY*/0x100);
		break;
	case 1:
//  syz_open_dev$dvb_dvr arguments: [
//    dev: ptr[in, buffer] {
//      buffer: {2f 64 65 76 2f 64 76 62 2f 61 64 61 70 74 65 72 23 2f 64 76 72 23 00} (length 0x17)
//    }
//    id: intptr = 0x0 (8 bytes)
//    flags: open_flags = 0x80003 (8 bytes)
//  ]
//  returns fd_dvb_dvr
memcpy((void*)0x200000000000, "/dev/dvb/adapter#/dvr#\000", 23);
syz_open_dev(/*dev=*/0x200000000000, /*id=*/0, /*flags=O_CLOEXEC|O_RDWR|O_WRONLY*/0x80003);
		break;
	case 2:
//  syz_open_dev$dvb_demux arguments: [
//    dev: ptr[in, buffer] {
//      buffer: {2f 64 65 76 2f 64 76 62 2f 61 64 61 70 74 65 72 23 2f 64 65 6d 75 78 23 00} (length 0x19)
//    }
//    id: intptr = 0x0 (8 bytes)
//    flags: open_flags = 0x80 (8 bytes)
//  ]
//  returns fd_dvb_demux
memcpy((void*)0x2000000000c0, "/dev/dvb/adapter#/demux#\000", 25);
syz_open_dev(/*dev=*/0x2000000000c0, /*id=*/0, /*flags=O_EXCL*/0x80);
		break;
	case 3:
//  syz_open_dev$dvb_frontend arguments: [
//    dev: ptr[in, buffer] {
//      buffer: {2f 64 65 76 2f 64 76 62 2f 61 64 61 70 74 65 72 23 2f 66 72 6f 6e 74 65 6e 64 23 00} (length 0x1c)
//    }
//    id: intptr = 0x0 (8 bytes)
//    flags: open_flags = 0x102 (8 bytes)
//  ]
//  returns fd_dvb_frontend
memcpy((void*)0x200000000000, "/dev/dvb/adapter#/frontend#\000", 28);
syz_open_dev(/*dev=*/0x200000000000, /*id=*/0, /*flags=O_NOCTTY|O_RDWR*/0x102);
		break;
	}

}
int main(void)
{
		syscall(__NR_mmap, /*addr=*/0x1ffffffff000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul);
	syscall(__NR_mmap, /*addr=*/0x200000000000ul, /*len=*/0x1000000ul, /*prot=PROT_WRITE|PROT_READ|PROT_EXEC*/7ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul);
	syscall(__NR_mmap, /*addr=*/0x200001000000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul);
	const char* reason;
	(void)reason;
	if ((reason = setup_swap()))
		printf("the reproducer may not work as expected: swap setup failed: %s\n", reason);
	for (procid = 0; procid < 8; procid++) {
		if (fork() == 0) {
			use_temporary_dir();
			do_sandbox_none();
		}
	}
	sleep(1000000);
	return 0;
}

Attachment: [kasan-suaf-write-dvb_device_open] repro.syz
Description: Binary data

Attachment: [kfence-uaf-read-dvb_frontend_release] kernel.log
Description: Binary data

Attachment: [kfence-uaf-read-dvb_frontend_release] report
Description: Binary data

Attachment: [warning-_dmxdev_lock] kernel.log
Description: Binary data

Attachment: [warning-_dmxdev_lock] report
Description: Binary data

Attachment: [warning-_dmxdev_unlock] report
Description: Binary data

Attachment: [warning-_dmxdev_unlock] kernel.log
Description: Binary data

Attachment: syzkaller-ac3c71e7.patch
Description: Binary data

Attachment: [kasan-suaf-read-dvb_frontend_release] repro.syz
Description: Binary data