[linux-2.6-block.git] / kernel / futex / syscalls.c

// SPDX-License-Identifier: GPL-2.0-or-later

#include <linux/syscalls.h>
#include <linux/time_namespace.h>

#include "futex.h"

/*
 * Support for robust futexes: the kernel cleans up held futexes at
 * thread exit time.
 *
 * Implementation: user-space maintains a per-thread list of locks it
 * is holding. Upon do_exit(), the kernel carefully walks this list,
 * and marks all locks that are owned by this thread with the
 * FUTEX_OWNER_DIED bit, and wakes up a waiter (if any). The list is
 * always manipulated with the lock held, so the list is private and
 * per-thread. Userspace also maintains a per-thread 'list_op_pending'
 * field, to allow the kernel to clean up if the thread dies after
 * acquiring the lock, but just before it could have added itself to
 * the list. There can only be one such pending lock.
 */

/**
 * sys_set_robust_list() - Set the robust-futex list head of a task
 * @head:	pointer to the list-head
 * @len:	length of the list-head, as userspace expects
 */
SYSCALL_DEFINE2(set_robust_list, struct robust_list_head __user *, head,
		size_t, len)
{
	/*
	 * The kernel knows only one size for now:
	 */
	if (unlikely(len != sizeof(*head)))
		return -EINVAL;

	current->robust_list = head;

	return 0;
}

/**
 * sys_get_robust_list() - Get the robust-futex list head of a task
 * @pid:	pid of the process [zero for current task]
 * @head_ptr:	pointer to a list-head pointer, the kernel fills it in
 * @len_ptr:	pointer to a length field, the kernel fills in the header size
 */
SYSCALL_DEFINE3(get_robust_list, int, pid,
		struct robust_list_head __user * __user *, head_ptr,
		size_t __user *, len_ptr)
{
	struct robust_list_head __user *head;
	unsigned long ret;
	struct task_struct *p;

	rcu_read_lock();

	ret = -ESRCH;
	if (!pid)
		p = current;
	else {
		p = find_task_by_vpid(pid);
		if (!p)
			goto err_unlock;
	}

	ret = -EPERM;
	if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
		goto err_unlock;

	head = p->robust_list;
	rcu_read_unlock();

	if (put_user(sizeof(*head), len_ptr))
		return -EFAULT;
	return put_user(head, head_ptr);

err_unlock:
	rcu_read_unlock();

	return ret;
}

long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
		u32 __user *uaddr2, u32 val2, u32 val3)
{
	unsigned int flags = futex_to_flags(op);
	int cmd = op & FUTEX_CMD_MASK;

	if (flags & FLAGS_CLOCKRT) {
		if (cmd != FUTEX_WAIT_BITSET &&
		    cmd != FUTEX_WAIT_REQUEUE_PI &&
		    cmd != FUTEX_LOCK_PI2)
			return -ENOSYS;
	}

	switch (cmd) {
	case FUTEX_WAIT:
		val3 = FUTEX_BITSET_MATCH_ANY;
		fallthrough;
	case FUTEX_WAIT_BITSET:
		return futex_wait(uaddr, flags, val, timeout, val3);
	case FUTEX_WAKE:
		val3 = FUTEX_BITSET_MATCH_ANY;
		fallthrough;
	case FUTEX_WAKE_BITSET:
		return futex_wake(uaddr, flags, val, val3);
	case FUTEX_REQUEUE:
		return futex_requeue(uaddr, flags, uaddr2, val, val2, NULL, 0);
	case FUTEX_CMP_REQUEUE:
		return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 0);
	case FUTEX_WAKE_OP:
		return futex_wake_op(uaddr, flags, uaddr2, val, val2, val3);
	case FUTEX_LOCK_PI:
		flags |= FLAGS_CLOCKRT;
		fallthrough;
	case FUTEX_LOCK_PI2:
		return futex_lock_pi(uaddr, flags, timeout, 0);
	case FUTEX_UNLOCK_PI:
		return futex_unlock_pi(uaddr, flags);
	case FUTEX_TRYLOCK_PI:
		return futex_lock_pi(uaddr, flags, NULL, 1);
	case FUTEX_WAIT_REQUEUE_PI:
		val3 = FUTEX_BITSET_MATCH_ANY;
		return futex_wait_requeue_pi(uaddr, flags, val, timeout, val3,
					     uaddr2);
	case FUTEX_CMP_REQUEUE_PI:
		return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 1);
	}
	return -ENOSYS;
}

static __always_inline bool futex_cmd_has_timeout(u32 cmd)
{
	switch (cmd) {
	case FUTEX_WAIT:
	case FUTEX_LOCK_PI:
	case FUTEX_LOCK_PI2:
	case FUTEX_WAIT_BITSET:
	case FUTEX_WAIT_REQUEUE_PI:
		return true;
	}
	return false;
}

static __always_inline int
futex_init_timeout(u32 cmd, u32 op, struct timespec64 *ts, ktime_t *t)
{
	if (!timespec64_valid(ts))
		return -EINVAL;

	*t = timespec64_to_ktime(*ts);
	if (cmd == FUTEX_WAIT)
		*t = ktime_add_safe(ktime_get(), *t);
	else if (cmd != FUTEX_LOCK_PI && !(op & FUTEX_CLOCK_REALTIME))
		*t = timens_ktime_to_host(CLOCK_MONOTONIC, *t);
	return 0;
}

SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
		const struct __kernel_timespec __user *, utime,
		u32 __user *, uaddr2, u32, val3)
{
	int ret, cmd = op & FUTEX_CMD_MASK;
	ktime_t t, *tp = NULL;
	struct timespec64 ts;

	if (utime && futex_cmd_has_timeout(cmd)) {
		if (unlikely(should_fail_futex(!(op & FUTEX_PRIVATE_FLAG))))
			return -EFAULT;
		if (get_timespec64(&ts, utime))
			return -EFAULT;
		ret = futex_init_timeout(cmd, op, &ts, &t);
		if (ret)
			return ret;
		tp = &t;
	}

	return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3);
}

#define FUTEX2_VALID_MASK (FUTEX2_SIZE_MASK | FUTEX2_PRIVATE)

/**
 * futex_parse_waitv - Parse a waitv array from userspace
 * @futexv:	Kernel side list of waiters to be filled
 * @uwaitv:     Userspace list to be parsed
 * @nr_futexes: Length of futexv
 *
 * Return: Error code on failure, 0 on success
 */
static int futex_parse_waitv(struct futex_vector *futexv,
			     struct futex_waitv __user *uwaitv,
			     unsigned int nr_futexes)
{
	struct futex_waitv aux;
	unsigned int i;

	for (i = 0; i < nr_futexes; i++) {
		unsigned int flags;

		if (copy_from_user(&aux, &uwaitv[i], sizeof(aux)))
			return -EFAULT;

		if ((aux.flags & ~FUTEX2_VALID_MASK) || aux.__reserved)
			return -EINVAL;

		flags = futex2_to_flags(aux.flags);
		if (!futex_flags_valid(flags))
			return -EINVAL;

		futexv[i].w.flags = flags;
		futexv[i].w.val = aux.val;
		futexv[i].w.uaddr = aux.uaddr;
		futexv[i].q = futex_q_init;
	}

	return 0;
}

/**
 * sys_futex_waitv - Wait on a list of futexes
 * @waiters:    List of futexes to wait on
 * @nr_futexes: Length of futexv
 * @flags:      Flag for timeout (monotonic/realtime)
 * @timeout:	Optional absolute timeout.
 * @clockid:	Clock to be used for the timeout, realtime or monotonic.
 *
 * Given an array of `struct futex_waitv`, wait on each uaddr. The thread wakes
 * if a futex_wake() is performed at any uaddr. The syscall returns immediately
 * if any waiter has *uaddr != val. *timeout is an optional timeout value for
 * the operation. Each waiter has individual flags. The `flags` argument for
 * the syscall should be used solely for specifying the timeout as realtime, if
 * needed. Flags for private futexes, sizes, etc. should be used on the
 * individual flags of each waiter.
 *
 * Returns the array index of one of the woken futexes. No further information
 * is provided: any number of other futexes may also have been woken by the
 * same event, and if more than one futex was woken, the retrned index may
 * refer to any one of them. (It is not necessaryily the futex with the
 * smallest index, nor the one most recently woken, nor...)
 */

SYSCALL_DEFINE5(futex_waitv, struct futex_waitv __user *, waiters,
		unsigned int, nr_futexes, unsigned int, flags,
		struct __kernel_timespec __user *, timeout, clockid_t, clockid)
{
	struct hrtimer_sleeper to;
	struct futex_vector *futexv;
	struct timespec64 ts;
	ktime_t time;
	int ret;

	/* This syscall supports no flags for now */
	if (flags)
		return -EINVAL;

	if (!nr_futexes || nr_futexes > FUTEX_WAITV_MAX || !waiters)
		return -EINVAL;

	if (timeout) {
		int flag_clkid = 0, flag_init = 0;

		if (clockid == CLOCK_REALTIME) {
			flag_clkid = FLAGS_CLOCKRT;
			flag_init = FUTEX_CLOCK_REALTIME;
		}

		if (clockid != CLOCK_REALTIME && clockid != CLOCK_MONOTONIC)
			return -EINVAL;

		if (get_timespec64(&ts, timeout))
			return -EFAULT;

		/*
		 * Since there's no opcode for futex_waitv, use
		 * FUTEX_WAIT_BITSET that uses absolute timeout as well
		 */
		ret = futex_init_timeout(FUTEX_WAIT_BITSET, flag_init, &ts, &time);
		if (ret)
			return ret;

		futex_setup_timer(&time, &to, flag_clkid, 0);
	}

	futexv = kcalloc(nr_futexes, sizeof(*futexv), GFP_KERNEL);
	if (!futexv) {
		ret = -ENOMEM;
		goto destroy_timer;
	}

	ret = futex_parse_waitv(futexv, waiters, nr_futexes);
	if (!ret)
		ret = futex_wait_multiple(futexv, nr_futexes, timeout ? &to : NULL);

	kfree(futexv);

destroy_timer:
	if (timeout) {
		hrtimer_cancel(&to.timer);
		destroy_hrtimer_on_stack(&to.timer);
	}
	return ret;
}

#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE2(set_robust_list,
		struct compat_robust_list_head __user *, head,
		compat_size_t, len)
{
	if (unlikely(len != sizeof(*head)))
		return -EINVAL;

	current->compat_robust_list = head;

	return 0;
}

COMPAT_SYSCALL_DEFINE3(get_robust_list, int, pid,
			compat_uptr_t __user *, head_ptr,
			compat_size_t __user *, len_ptr)
{
	struct compat_robust_list_head __user *head;
	unsigned long ret;
	struct task_struct *p;

	rcu_read_lock();

	ret = -ESRCH;
	if (!pid)
		p = current;
	else {
		p = find_task_by_vpid(pid);
		if (!p)
			goto err_unlock;
	}

	ret = -EPERM;
	if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
		goto err_unlock;

	head = p->compat_robust_list;
	rcu_read_unlock();

	if (put_user(sizeof(*head), len_ptr))
		return -EFAULT;
	return put_user(ptr_to_compat(head), head_ptr);

err_unlock:
	rcu_read_unlock();

	return ret;
}
#endif /* CONFIG_COMPAT */

#ifdef CONFIG_COMPAT_32BIT_TIME
SYSCALL_DEFINE6(futex_time32, u32 __user *, uaddr, int, op, u32, val,
		const struct old_timespec32 __user *, utime, u32 __user *, uaddr2,
		u32, val3)
{
	int ret, cmd = op & FUTEX_CMD_MASK;
	ktime_t t, *tp = NULL;
	struct timespec64 ts;

	if (utime && futex_cmd_has_timeout(cmd)) {
		if (get_old_timespec32(&ts, utime))
			return -EFAULT;
		ret = futex_init_timeout(cmd, op, &ts, &t);
		if (ret)
			return ret;
		tp = &t;
	}

	return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3);
}
#endif /* CONFIG_COMPAT_32BIT_TIME */
Commit	Line	Data
af8cc960 PZ	1	// SPDX-License-Identifier: GPL-2.0-or-later
af8cc960 PZ	2
af8cc960 PZ	3	#include <linux/syscalls.h>
	4	#include <linux/time_namespace.h>
	5
	6	#include "futex.h"
	7
	8	/*
	9	* Support for robust futexes: the kernel cleans up held futexes at
	10	* thread exit time.
	11	*
	12	* Implementation: user-space maintains a per-thread list of locks it
	13	* is holding. Upon do_exit(), the kernel carefully walks this list,
	14	* and marks all locks that are owned by this thread with the
	15	* FUTEX_OWNER_DIED bit, and wakes up a waiter (if any). The list is
	16	* always manipulated with the lock held, so the list is private and
	17	* per-thread. Userspace also maintains a per-thread 'list_op_pending'
	18	* field, to allow the kernel to clean up if the thread dies after
	19	* acquiring the lock, but just before it could have added itself to
	20	* the list. There can only be one such pending lock.
	21	*/
	22
	23	/**
	24	* sys_set_robust_list() - Set the robust-futex list head of a task
	25	* @head: pointer to the list-head
	26	* @len: length of the list-head, as userspace expects
	27	*/
	28	SYSCALL_DEFINE2(set_robust_list, struct robust_list_head __user *, head,
	29	size_t, len)
	30	{
af8cc960 PZ	31	/*
	32	* The kernel knows only one size for now:
	33	*/
	34	if (unlikely(len != sizeof(*head)))
	35	return -EINVAL;
	36
	37	current->robust_list = head;
	38
	39	return 0;
	40	}
	41
	42	/**
	43	* sys_get_robust_list() - Get the robust-futex list head of a task
	44	* @pid: pid of the process [zero for current task]
	45	* @head_ptr: pointer to a list-head pointer, the kernel fills it in
	46	* @len_ptr: pointer to a length field, the kernel fills in the header size
	47	*/
	48	SYSCALL_DEFINE3(get_robust_list, int, pid,
	49	struct robust_list_head __user * __user *, head_ptr,
	50	size_t __user *, len_ptr)
	51	{
	52	struct robust_list_head __user *head;
	53	unsigned long ret;
	54	struct task_struct *p;
	55
af8cc960 PZ	56	rcu_read_lock();
	57
	58	ret = -ESRCH;
	59	if (!pid)
	60	p = current;
	61	else {
	62	p = find_task_by_vpid(pid);
	63	if (!p)
	64	goto err_unlock;
	65	}
	66
	67	ret = -EPERM;
	68	if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
	69	goto err_unlock;
	70
	71	head = p->robust_list;
	72	rcu_read_unlock();
	73
	74	if (put_user(sizeof(*head), len_ptr))
	75	return -EFAULT;
	76	return put_user(head, head_ptr);
	77
	78	err_unlock:
	79	rcu_read_unlock();
	80
	81	return ret;
	82	}
	83
	84	long do_futex(u32 __user uaddr, int op, u32 val, ktime_t timeout,
	85	u32 __user *uaddr2, u32 val2, u32 val3)
	86	{
5694289c	87	unsigned int flags = futex_to_flags(op);
af8cc960	88	int cmd = op & FUTEX_CMD_MASK;
af8cc960	89
5694289c	90	if (flags & FLAGS_CLOCKRT) {
	91	if (cmd != FUTEX_WAIT_BITSET &&
	92	cmd != FUTEX_WAIT_REQUEUE_PI &&
af8cc960 PZ	93	cmd != FUTEX_LOCK_PI2)
	94	return -ENOSYS;
	95	}
	96
af8cc960 PZ	97	switch (cmd) {
	98	case FUTEX_WAIT:
	99	val3 = FUTEX_BITSET_MATCH_ANY;
	100	fallthrough;
	101	case FUTEX_WAIT_BITSET:
	102	return futex_wait(uaddr, flags, val, timeout, val3);
	103	case FUTEX_WAKE:
	104	val3 = FUTEX_BITSET_MATCH_ANY;
	105	fallthrough;
	106	case FUTEX_WAKE_BITSET:
	107	return futex_wake(uaddr, flags, val, val3);
	108	case FUTEX_REQUEUE:
	109	return futex_requeue(uaddr, flags, uaddr2, val, val2, NULL, 0);
	110	case FUTEX_CMP_REQUEUE:
	111	return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 0);
	112	case FUTEX_WAKE_OP:
	113	return futex_wake_op(uaddr, flags, uaddr2, val, val2, val3);
	114	case FUTEX_LOCK_PI:
	115	flags \|= FLAGS_CLOCKRT;
	116	fallthrough;
	117	case FUTEX_LOCK_PI2:
	118	return futex_lock_pi(uaddr, flags, timeout, 0);
	119	case FUTEX_UNLOCK_PI:
	120	return futex_unlock_pi(uaddr, flags);
	121	case FUTEX_TRYLOCK_PI:
	122	return futex_lock_pi(uaddr, flags, NULL, 1);
	123	case FUTEX_WAIT_REQUEUE_PI:
	124	val3 = FUTEX_BITSET_MATCH_ANY;
	125	return futex_wait_requeue_pi(uaddr, flags, val, timeout, val3,
	126	uaddr2);
	127	case FUTEX_CMP_REQUEUE_PI:
	128	return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 1);
	129	}
	130	return -ENOSYS;
	131	}
	132
	133	static __always_inline bool futex_cmd_has_timeout(u32 cmd)
	134	{
	135	switch (cmd) {
	136	case FUTEX_WAIT:
	137	case FUTEX_LOCK_PI:
	138	case FUTEX_LOCK_PI2:
	139	case FUTEX_WAIT_BITSET:
	140	case FUTEX_WAIT_REQUEUE_PI:
	141	return true;
	142	}
	143	return false;
	144	}
	145
	146	static __always_inline int
	147	futex_init_timeout(u32 cmd, u32 op, struct timespec64 ts, ktime_t t)
	148	{
	149	if (!timespec64_valid(ts))
	150	return -EINVAL;
	151
	152	t = timespec64_to_ktime(ts);
	153	if (cmd == FUTEX_WAIT)
	154	t = ktime_add_safe(ktime_get(), t);
	155	else if (cmd != FUTEX_LOCK_PI && !(op & FUTEX_CLOCK_REALTIME))
	156	t = timens_ktime_to_host(CLOCK_MONOTONIC, t);
	157	return 0;
	158	}
	159
	160	SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
161	const struct __kernel_timespec __user *, utime,
162	u32 __user *, uaddr2, u32, val3)
163	{
164	int ret, cmd = op & FUTEX_CMD_MASK;
165	ktime_t t, *tp = NULL;
166	struct timespec64 ts;
167
168	if (utime && futex_cmd_has_timeout(cmd)) {
169	if (unlikely(should_fail_futex(!(op & FUTEX_PRIVATE_FLAG))))
170	return -EFAULT;
171	if (get_timespec64(&ts, utime))
172	return -EFAULT;
173	ret = futex_init_timeout(cmd, op, &ts, &t);
174	if (ret)
175	return ret;
176	tp = &t;
177	}
178
179	return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3);
180	}
181
d6d08d24	182	#define FUTEX2_VALID_MASK (FUTEX2_SIZE_MASK \| FUTEX2_PRIVATE)
bf69bad3 AA	183
	184	/**
	185	* futex_parse_waitv - Parse a waitv array from userspace
	186	* @futexv: Kernel side list of waiters to be filled
	187	* @uwaitv: Userspace list to be parsed
	188	* @nr_futexes: Length of futexv
	189	*
	190	* Return: Error code on failure, 0 on success
	191	*/
	192	static int futex_parse_waitv(struct futex_vector *futexv,
	193	struct futex_waitv __user *uwaitv,
	194	unsigned int nr_futexes)
	195	{
	196	struct futex_waitv aux;
	197	unsigned int i;
	198
	199	for (i = 0; i < nr_futexes; i++) {
5694289c	200	unsigned int flags;
5694289c	201
bf69bad3 AA	202	if (copy_from_user(&aux, &uwaitv[i], sizeof(aux)))
	203	return -EFAULT;
	204
4923954b	205	if ((aux.flags & ~FUTEX2_VALID_MASK) \|\| aux.__reserved)
bf69bad3 AA	206	return -EINVAL;
bf69bad3 AA	207
5694289c	208	flags = futex2_to_flags(aux.flags);
5694289c	209	if (!futex_flags_valid(flags))
bf69bad3 AA	210	return -EINVAL;
bf69bad3 AA	211
5694289c	212	futexv[i].w.flags = flags;
bf69bad3 AA	213	futexv[i].w.val = aux.val;
	214	futexv[i].w.uaddr = aux.uaddr;
	215	futexv[i].q = futex_q_init;
	216	}
	217
	218	return 0;
	219	}
	220
	221	/**
	222	* sys_futex_waitv - Wait on a list of futexes
	223	* @waiters: List of futexes to wait on
	224	* @nr_futexes: Length of futexv
	225	* @flags: Flag for timeout (monotonic/realtime)
	226	* @timeout: Optional absolute timeout.
	227	* @clockid: Clock to be used for the timeout, realtime or monotonic.
	228	*
	229	* Given an array of `struct futex_waitv`, wait on each uaddr. The thread wakes
	230	* if a futex_wake() is performed at any uaddr. The syscall returns immediately
	231	* if any waiter has uaddr != val. timeout is an optional timeout value for
	232	* the operation. Each waiter has individual flags. The `flags` argument for
	233	* the syscall should be used solely for specifying the timeout as realtime, if
	234	* needed. Flags for private futexes, sizes, etc. should be used on the
	235	* individual flags of each waiter.
	236	*
	237	* Returns the array index of one of the woken futexes. No further information
	238	* is provided: any number of other futexes may also have been woken by the
	239	* same event, and if more than one futex was woken, the retrned index may
	240	* refer to any one of them. (It is not necessaryily the futex with the
	241	* smallest index, nor the one most recently woken, nor...)
	242	*/
	243
	244	SYSCALL_DEFINE5(futex_waitv, struct futex_waitv __user *, waiters,
	245	unsigned int, nr_futexes, unsigned int, flags,
	246	struct __kernel_timespec __user *, timeout, clockid_t, clockid)
	247	{
	248	struct hrtimer_sleeper to;
	249	struct futex_vector *futexv;
	250	struct timespec64 ts;
	251	ktime_t time;
	252	int ret;
	253
	254	/* This syscall supports no flags for now */
	255	if (flags)
	256	return -EINVAL;
	257
	258	if (!nr_futexes \|\| nr_futexes > FUTEX_WAITV_MAX \|\| !waiters)
	259	return -EINVAL;
	260
	261	if (timeout) {
	262	int flag_clkid = 0, flag_init = 0;
	263
	264	if (clockid == CLOCK_REALTIME) {
	265	flag_clkid = FLAGS_CLOCKRT;
	266	flag_init = FUTEX_CLOCK_REALTIME;
	267	}
	268
	269	if (clockid != CLOCK_REALTIME && clockid != CLOCK_MONOTONIC)
	270	return -EINVAL;
	271
	272	if (get_timespec64(&ts, timeout))
	273	return -EFAULT;
	274
	275	/*
	276	* Since there's no opcode for futex_waitv, use
277	* FUTEX_WAIT_BITSET that uses absolute timeout as well
278	*/
279	ret = futex_init_timeout(FUTEX_WAIT_BITSET, flag_init, &ts, &time);
280	if (ret)
281	return ret;
282
283	futex_setup_timer(&time, &to, flag_clkid, 0);
284	}
285
286	futexv = kcalloc(nr_futexes, sizeof(*futexv), GFP_KERNEL);
94cd8fa0 MD	287	if (!futexv) {
	288	ret = -ENOMEM;
	289	goto destroy_timer;
	290	}
bf69bad3 AA	291
	292	ret = futex_parse_waitv(futexv, waiters, nr_futexes);
	293	if (!ret)
	294	ret = futex_wait_multiple(futexv, nr_futexes, timeout ? &to : NULL);
	295
94cd8fa0 MD	296	kfree(futexv);
	297
	298	destroy_timer:
bf69bad3 AA	299	if (timeout) {
	300	hrtimer_cancel(&to.timer);
	301	destroy_hrtimer_on_stack(&to.timer);
	302	}
bf69bad3 AA	303	return ret;
	304	}
	305
af8cc960 PZ	306	#ifdef CONFIG_COMPAT
	307	COMPAT_SYSCALL_DEFINE2(set_robust_list,
	308	struct compat_robust_list_head __user *, head,
	309	compat_size_t, len)
	310	{
af8cc960 PZ	311	if (unlikely(len != sizeof(*head)))
	312	return -EINVAL;
	313
	314	current->compat_robust_list = head;
	315
	316	return 0;
	317	}
	318
	319	COMPAT_SYSCALL_DEFINE3(get_robust_list, int, pid,
	320	compat_uptr_t __user *, head_ptr,
	321	compat_size_t __user *, len_ptr)
	322	{
	323	struct compat_robust_list_head __user *head;
	324	unsigned long ret;
	325	struct task_struct *p;
	326
af8cc960 PZ	327	rcu_read_lock();
	328
	329	ret = -ESRCH;
	330	if (!pid)
	331	p = current;
	332	else {
	333	p = find_task_by_vpid(pid);
	334	if (!p)
	335	goto err_unlock;
	336	}
	337
	338	ret = -EPERM;
	339	if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
	340	goto err_unlock;
	341
	342	head = p->compat_robust_list;
	343	rcu_read_unlock();
	344
	345	if (put_user(sizeof(*head), len_ptr))
	346	return -EFAULT;
	347	return put_user(ptr_to_compat(head), head_ptr);
	348
	349	err_unlock:
	350	rcu_read_unlock();
	351
	352	return ret;
	353	}
	354	#endif /* CONFIG_COMPAT */
	355
	356	#ifdef CONFIG_COMPAT_32BIT_TIME
	357	SYSCALL_DEFINE6(futex_time32, u32 __user *, uaddr, int, op, u32, val,
	358	const struct old_timespec32 __user , utime, u32 __user , uaddr2,
	359	u32, val3)
	360	{
	361	int ret, cmd = op & FUTEX_CMD_MASK;
	362	ktime_t t, *tp = NULL;
	363	struct timespec64 ts;
	364
	365	if (utime && futex_cmd_has_timeout(cmd)) {
	366	if (get_old_timespec32(&ts, utime))
	367	return -EFAULT;
	368	ret = futex_init_timeout(cmd, op, &ts, &t);
	369	if (ret)
	370	return ret;
	371	tp = &t;
	372	}
	373
	374	return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3);
	375	}
	376	#endif /* CONFIG_COMPAT_32BIT_TIME */
	377