1af8cc960SPeter Zijlstra // SPDX-License-Identifier: GPL-2.0-or-later
2af8cc960SPeter Zijlstra
3af8cc960SPeter Zijlstra #include <linux/compat.h>
4af8cc960SPeter Zijlstra #include <linux/syscalls.h>
5af8cc960SPeter Zijlstra #include <linux/time_namespace.h>
6af8cc960SPeter Zijlstra
7af8cc960SPeter Zijlstra #include "futex.h"
8af8cc960SPeter Zijlstra
9af8cc960SPeter Zijlstra /*
10af8cc960SPeter Zijlstra * Support for robust futexes: the kernel cleans up held futexes at
11af8cc960SPeter Zijlstra * thread exit time.
12af8cc960SPeter Zijlstra *
13af8cc960SPeter Zijlstra * Implementation: user-space maintains a per-thread list of locks it
14af8cc960SPeter Zijlstra * is holding. Upon do_exit(), the kernel carefully walks this list,
15af8cc960SPeter Zijlstra * and marks all locks that are owned by this thread with the
16af8cc960SPeter Zijlstra * FUTEX_OWNER_DIED bit, and wakes up a waiter (if any). The list is
17af8cc960SPeter Zijlstra * always manipulated with the lock held, so the list is private and
18af8cc960SPeter Zijlstra * per-thread. Userspace also maintains a per-thread 'list_op_pending'
19af8cc960SPeter Zijlstra * field, to allow the kernel to clean up if the thread dies after
20af8cc960SPeter Zijlstra * acquiring the lock, but just before it could have added itself to
21af8cc960SPeter Zijlstra * the list. There can only be one such pending lock.
22af8cc960SPeter Zijlstra */
23af8cc960SPeter Zijlstra
24af8cc960SPeter Zijlstra /**
25af8cc960SPeter Zijlstra * sys_set_robust_list() - Set the robust-futex list head of a task
26af8cc960SPeter Zijlstra * @head: pointer to the list-head
27af8cc960SPeter Zijlstra * @len: length of the list-head, as userspace expects
28af8cc960SPeter Zijlstra */
SYSCALL_DEFINE2(set_robust_list,struct robust_list_head __user *,head,size_t,len)29af8cc960SPeter Zijlstra SYSCALL_DEFINE2(set_robust_list, struct robust_list_head __user *, head,
30af8cc960SPeter Zijlstra size_t, len)
31af8cc960SPeter Zijlstra {
32af8cc960SPeter Zijlstra /*
33af8cc960SPeter Zijlstra * The kernel knows only one size for now:
34af8cc960SPeter Zijlstra */
35af8cc960SPeter Zijlstra if (unlikely(len != sizeof(*head)))
36af8cc960SPeter Zijlstra return -EINVAL;
37af8cc960SPeter Zijlstra
38af8cc960SPeter Zijlstra current->robust_list = head;
39af8cc960SPeter Zijlstra
40af8cc960SPeter Zijlstra return 0;
41af8cc960SPeter Zijlstra }
42af8cc960SPeter Zijlstra
43af8cc960SPeter Zijlstra /**
44af8cc960SPeter Zijlstra * sys_get_robust_list() - Get the robust-futex list head of a task
45af8cc960SPeter Zijlstra * @pid: pid of the process [zero for current task]
46af8cc960SPeter Zijlstra * @head_ptr: pointer to a list-head pointer, the kernel fills it in
47af8cc960SPeter Zijlstra * @len_ptr: pointer to a length field, the kernel fills in the header size
48af8cc960SPeter Zijlstra */
SYSCALL_DEFINE3(get_robust_list,int,pid,struct robust_list_head __user * __user *,head_ptr,size_t __user *,len_ptr)49af8cc960SPeter Zijlstra SYSCALL_DEFINE3(get_robust_list, int, pid,
50af8cc960SPeter Zijlstra struct robust_list_head __user * __user *, head_ptr,
51af8cc960SPeter Zijlstra size_t __user *, len_ptr)
52af8cc960SPeter Zijlstra {
53af8cc960SPeter Zijlstra struct robust_list_head __user *head;
54af8cc960SPeter Zijlstra unsigned long ret;
55af8cc960SPeter Zijlstra struct task_struct *p;
56af8cc960SPeter Zijlstra
57af8cc960SPeter Zijlstra rcu_read_lock();
58af8cc960SPeter Zijlstra
59af8cc960SPeter Zijlstra ret = -ESRCH;
60af8cc960SPeter Zijlstra if (!pid)
61af8cc960SPeter Zijlstra p = current;
62af8cc960SPeter Zijlstra else {
63af8cc960SPeter Zijlstra p = find_task_by_vpid(pid);
64af8cc960SPeter Zijlstra if (!p)
65af8cc960SPeter Zijlstra goto err_unlock;
66af8cc960SPeter Zijlstra }
67af8cc960SPeter Zijlstra
68af8cc960SPeter Zijlstra ret = -EPERM;
69af8cc960SPeter Zijlstra if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
70af8cc960SPeter Zijlstra goto err_unlock;
71af8cc960SPeter Zijlstra
72af8cc960SPeter Zijlstra head = p->robust_list;
73af8cc960SPeter Zijlstra rcu_read_unlock();
74af8cc960SPeter Zijlstra
75af8cc960SPeter Zijlstra if (put_user(sizeof(*head), len_ptr))
76af8cc960SPeter Zijlstra return -EFAULT;
77af8cc960SPeter Zijlstra return put_user(head, head_ptr);
78af8cc960SPeter Zijlstra
79af8cc960SPeter Zijlstra err_unlock:
80af8cc960SPeter Zijlstra rcu_read_unlock();
81af8cc960SPeter Zijlstra
82af8cc960SPeter Zijlstra return ret;
83af8cc960SPeter Zijlstra }
84af8cc960SPeter Zijlstra
do_futex(u32 __user * uaddr,int op,u32 val,ktime_t * timeout,u32 __user * uaddr2,u32 val2,u32 val3)85af8cc960SPeter Zijlstra long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
86af8cc960SPeter Zijlstra u32 __user *uaddr2, u32 val2, u32 val3)
87af8cc960SPeter Zijlstra {
88af8cc960SPeter Zijlstra int cmd = op & FUTEX_CMD_MASK;
89af8cc960SPeter Zijlstra unsigned int flags = 0;
90af8cc960SPeter Zijlstra
91af8cc960SPeter Zijlstra if (!(op & FUTEX_PRIVATE_FLAG))
92af8cc960SPeter Zijlstra flags |= FLAGS_SHARED;
93af8cc960SPeter Zijlstra
94af8cc960SPeter Zijlstra if (op & FUTEX_CLOCK_REALTIME) {
95af8cc960SPeter Zijlstra flags |= FLAGS_CLOCKRT;
96af8cc960SPeter Zijlstra if (cmd != FUTEX_WAIT_BITSET && cmd != FUTEX_WAIT_REQUEUE_PI &&
97af8cc960SPeter Zijlstra cmd != FUTEX_LOCK_PI2)
98af8cc960SPeter Zijlstra return -ENOSYS;
99af8cc960SPeter Zijlstra }
100af8cc960SPeter Zijlstra
101af8cc960SPeter Zijlstra switch (cmd) {
102af8cc960SPeter Zijlstra case FUTEX_WAIT:
103af8cc960SPeter Zijlstra val3 = FUTEX_BITSET_MATCH_ANY;
104af8cc960SPeter Zijlstra fallthrough;
105af8cc960SPeter Zijlstra case FUTEX_WAIT_BITSET:
106af8cc960SPeter Zijlstra return futex_wait(uaddr, flags, val, timeout, val3);
107af8cc960SPeter Zijlstra case FUTEX_WAKE:
108af8cc960SPeter Zijlstra val3 = FUTEX_BITSET_MATCH_ANY;
109af8cc960SPeter Zijlstra fallthrough;
110af8cc960SPeter Zijlstra case FUTEX_WAKE_BITSET:
111af8cc960SPeter Zijlstra return futex_wake(uaddr, flags, val, val3);
112af8cc960SPeter Zijlstra case FUTEX_REQUEUE:
113af8cc960SPeter Zijlstra return futex_requeue(uaddr, flags, uaddr2, val, val2, NULL, 0);
114af8cc960SPeter Zijlstra case FUTEX_CMP_REQUEUE:
115af8cc960SPeter Zijlstra return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 0);
116af8cc960SPeter Zijlstra case FUTEX_WAKE_OP:
117af8cc960SPeter Zijlstra return futex_wake_op(uaddr, flags, uaddr2, val, val2, val3);
118af8cc960SPeter Zijlstra case FUTEX_LOCK_PI:
119af8cc960SPeter Zijlstra flags |= FLAGS_CLOCKRT;
120af8cc960SPeter Zijlstra fallthrough;
121af8cc960SPeter Zijlstra case FUTEX_LOCK_PI2:
122af8cc960SPeter Zijlstra return futex_lock_pi(uaddr, flags, timeout, 0);
123af8cc960SPeter Zijlstra case FUTEX_UNLOCK_PI:
124af8cc960SPeter Zijlstra return futex_unlock_pi(uaddr, flags);
125af8cc960SPeter Zijlstra case FUTEX_TRYLOCK_PI:
126af8cc960SPeter Zijlstra return futex_lock_pi(uaddr, flags, NULL, 1);
127af8cc960SPeter Zijlstra case FUTEX_WAIT_REQUEUE_PI:
128af8cc960SPeter Zijlstra val3 = FUTEX_BITSET_MATCH_ANY;
129af8cc960SPeter Zijlstra return futex_wait_requeue_pi(uaddr, flags, val, timeout, val3,
130af8cc960SPeter Zijlstra uaddr2);
131af8cc960SPeter Zijlstra case FUTEX_CMP_REQUEUE_PI:
132af8cc960SPeter Zijlstra return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 1);
133af8cc960SPeter Zijlstra }
134af8cc960SPeter Zijlstra return -ENOSYS;
135af8cc960SPeter Zijlstra }
136af8cc960SPeter Zijlstra
futex_cmd_has_timeout(u32 cmd)137af8cc960SPeter Zijlstra static __always_inline bool futex_cmd_has_timeout(u32 cmd)
138af8cc960SPeter Zijlstra {
139af8cc960SPeter Zijlstra switch (cmd) {
140af8cc960SPeter Zijlstra case FUTEX_WAIT:
141af8cc960SPeter Zijlstra case FUTEX_LOCK_PI:
142af8cc960SPeter Zijlstra case FUTEX_LOCK_PI2:
143af8cc960SPeter Zijlstra case FUTEX_WAIT_BITSET:
144af8cc960SPeter Zijlstra case FUTEX_WAIT_REQUEUE_PI:
145af8cc960SPeter Zijlstra return true;
146af8cc960SPeter Zijlstra }
147af8cc960SPeter Zijlstra return false;
148af8cc960SPeter Zijlstra }
149af8cc960SPeter Zijlstra
150af8cc960SPeter Zijlstra static __always_inline int
futex_init_timeout(u32 cmd,u32 op,struct timespec64 * ts,ktime_t * t)151af8cc960SPeter Zijlstra futex_init_timeout(u32 cmd, u32 op, struct timespec64 *ts, ktime_t *t)
152af8cc960SPeter Zijlstra {
153af8cc960SPeter Zijlstra if (!timespec64_valid(ts))
154af8cc960SPeter Zijlstra return -EINVAL;
155af8cc960SPeter Zijlstra
156af8cc960SPeter Zijlstra *t = timespec64_to_ktime(*ts);
157af8cc960SPeter Zijlstra if (cmd == FUTEX_WAIT)
158af8cc960SPeter Zijlstra *t = ktime_add_safe(ktime_get(), *t);
159af8cc960SPeter Zijlstra else if (cmd != FUTEX_LOCK_PI && !(op & FUTEX_CLOCK_REALTIME))
160af8cc960SPeter Zijlstra *t = timens_ktime_to_host(CLOCK_MONOTONIC, *t);
161af8cc960SPeter Zijlstra return 0;
162af8cc960SPeter Zijlstra }
163af8cc960SPeter Zijlstra
SYSCALL_DEFINE6(futex,u32 __user *,uaddr,int,op,u32,val,const struct __kernel_timespec __user *,utime,u32 __user *,uaddr2,u32,val3)164af8cc960SPeter Zijlstra SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
165af8cc960SPeter Zijlstra const struct __kernel_timespec __user *, utime,
166af8cc960SPeter Zijlstra u32 __user *, uaddr2, u32, val3)
167af8cc960SPeter Zijlstra {
168af8cc960SPeter Zijlstra int ret, cmd = op & FUTEX_CMD_MASK;
169af8cc960SPeter Zijlstra ktime_t t, *tp = NULL;
170af8cc960SPeter Zijlstra struct timespec64 ts;
171af8cc960SPeter Zijlstra
172af8cc960SPeter Zijlstra if (utime && futex_cmd_has_timeout(cmd)) {
173af8cc960SPeter Zijlstra if (unlikely(should_fail_futex(!(op & FUTEX_PRIVATE_FLAG))))
174af8cc960SPeter Zijlstra return -EFAULT;
175af8cc960SPeter Zijlstra if (get_timespec64(&ts, utime))
176af8cc960SPeter Zijlstra return -EFAULT;
177af8cc960SPeter Zijlstra ret = futex_init_timeout(cmd, op, &ts, &t);
178af8cc960SPeter Zijlstra if (ret)
179af8cc960SPeter Zijlstra return ret;
180af8cc960SPeter Zijlstra tp = &t;
181af8cc960SPeter Zijlstra }
182af8cc960SPeter Zijlstra
183af8cc960SPeter Zijlstra return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3);
184af8cc960SPeter Zijlstra }
185af8cc960SPeter Zijlstra
186bf69bad3SAndré Almeida /* Mask of available flags for each futex in futex_waitv list */
187bf69bad3SAndré Almeida #define FUTEXV_WAITER_MASK (FUTEX_32 | FUTEX_PRIVATE_FLAG)
188bf69bad3SAndré Almeida
189bf69bad3SAndré Almeida /**
190bf69bad3SAndré Almeida * futex_parse_waitv - Parse a waitv array from userspace
191bf69bad3SAndré Almeida * @futexv: Kernel side list of waiters to be filled
192bf69bad3SAndré Almeida * @uwaitv: Userspace list to be parsed
193bf69bad3SAndré Almeida * @nr_futexes: Length of futexv
194bf69bad3SAndré Almeida *
195bf69bad3SAndré Almeida * Return: Error code on failure, 0 on success
196bf69bad3SAndré Almeida */
futex_parse_waitv(struct futex_vector * futexv,struct futex_waitv __user * uwaitv,unsigned int nr_futexes)197bf69bad3SAndré Almeida static int futex_parse_waitv(struct futex_vector *futexv,
198bf69bad3SAndré Almeida struct futex_waitv __user *uwaitv,
199bf69bad3SAndré Almeida unsigned int nr_futexes)
200bf69bad3SAndré Almeida {
201bf69bad3SAndré Almeida struct futex_waitv aux;
202bf69bad3SAndré Almeida unsigned int i;
203bf69bad3SAndré Almeida
204bf69bad3SAndré Almeida for (i = 0; i < nr_futexes; i++) {
205bf69bad3SAndré Almeida if (copy_from_user(&aux, &uwaitv[i], sizeof(aux)))
206bf69bad3SAndré Almeida return -EFAULT;
207bf69bad3SAndré Almeida
208bf69bad3SAndré Almeida if ((aux.flags & ~FUTEXV_WAITER_MASK) || aux.__reserved)
209bf69bad3SAndré Almeida return -EINVAL;
210bf69bad3SAndré Almeida
211bf69bad3SAndré Almeida if (!(aux.flags & FUTEX_32))
212bf69bad3SAndré Almeida return -EINVAL;
213bf69bad3SAndré Almeida
214bf69bad3SAndré Almeida futexv[i].w.flags = aux.flags;
215bf69bad3SAndré Almeida futexv[i].w.val = aux.val;
216bf69bad3SAndré Almeida futexv[i].w.uaddr = aux.uaddr;
217bf69bad3SAndré Almeida futexv[i].q = futex_q_init;
218bf69bad3SAndré Almeida }
219bf69bad3SAndré Almeida
220bf69bad3SAndré Almeida return 0;
221bf69bad3SAndré Almeida }
222bf69bad3SAndré Almeida
223bf69bad3SAndré Almeida /**
224bf69bad3SAndré Almeida * sys_futex_waitv - Wait on a list of futexes
225bf69bad3SAndré Almeida * @waiters: List of futexes to wait on
226bf69bad3SAndré Almeida * @nr_futexes: Length of futexv
227bf69bad3SAndré Almeida * @flags: Flag for timeout (monotonic/realtime)
228bf69bad3SAndré Almeida * @timeout: Optional absolute timeout.
229bf69bad3SAndré Almeida * @clockid: Clock to be used for the timeout, realtime or monotonic.
230bf69bad3SAndré Almeida *
231bf69bad3SAndré Almeida * Given an array of `struct futex_waitv`, wait on each uaddr. The thread wakes
232bf69bad3SAndré Almeida * if a futex_wake() is performed at any uaddr. The syscall returns immediately
233bf69bad3SAndré Almeida * if any waiter has *uaddr != val. *timeout is an optional timeout value for
234bf69bad3SAndré Almeida * the operation. Each waiter has individual flags. The `flags` argument for
235bf69bad3SAndré Almeida * the syscall should be used solely for specifying the timeout as realtime, if
236bf69bad3SAndré Almeida * needed. Flags for private futexes, sizes, etc. should be used on the
237bf69bad3SAndré Almeida * individual flags of each waiter.
238bf69bad3SAndré Almeida *
239bf69bad3SAndré Almeida * Returns the array index of one of the woken futexes. No further information
240bf69bad3SAndré Almeida * is provided: any number of other futexes may also have been woken by the
241bf69bad3SAndré Almeida * same event, and if more than one futex was woken, the retrned index may
242bf69bad3SAndré Almeida * refer to any one of them. (It is not necessaryily the futex with the
243bf69bad3SAndré Almeida * smallest index, nor the one most recently woken, nor...)
244bf69bad3SAndré Almeida */
245bf69bad3SAndré Almeida
SYSCALL_DEFINE5(futex_waitv,struct futex_waitv __user *,waiters,unsigned int,nr_futexes,unsigned int,flags,struct __kernel_timespec __user *,timeout,clockid_t,clockid)246bf69bad3SAndré Almeida SYSCALL_DEFINE5(futex_waitv, struct futex_waitv __user *, waiters,
247bf69bad3SAndré Almeida unsigned int, nr_futexes, unsigned int, flags,
248bf69bad3SAndré Almeida struct __kernel_timespec __user *, timeout, clockid_t, clockid)
249bf69bad3SAndré Almeida {
250bf69bad3SAndré Almeida struct hrtimer_sleeper to;
251bf69bad3SAndré Almeida struct futex_vector *futexv;
252bf69bad3SAndré Almeida struct timespec64 ts;
253bf69bad3SAndré Almeida ktime_t time;
254bf69bad3SAndré Almeida int ret;
255bf69bad3SAndré Almeida
256bf69bad3SAndré Almeida /* This syscall supports no flags for now */
257bf69bad3SAndré Almeida if (flags)
258bf69bad3SAndré Almeida return -EINVAL;
259bf69bad3SAndré Almeida
260bf69bad3SAndré Almeida if (!nr_futexes || nr_futexes > FUTEX_WAITV_MAX || !waiters)
261bf69bad3SAndré Almeida return -EINVAL;
262bf69bad3SAndré Almeida
263bf69bad3SAndré Almeida if (timeout) {
264bf69bad3SAndré Almeida int flag_clkid = 0, flag_init = 0;
265bf69bad3SAndré Almeida
266bf69bad3SAndré Almeida if (clockid == CLOCK_REALTIME) {
267bf69bad3SAndré Almeida flag_clkid = FLAGS_CLOCKRT;
268bf69bad3SAndré Almeida flag_init = FUTEX_CLOCK_REALTIME;
269bf69bad3SAndré Almeida }
270bf69bad3SAndré Almeida
271bf69bad3SAndré Almeida if (clockid != CLOCK_REALTIME && clockid != CLOCK_MONOTONIC)
272bf69bad3SAndré Almeida return -EINVAL;
273bf69bad3SAndré Almeida
274bf69bad3SAndré Almeida if (get_timespec64(&ts, timeout))
275bf69bad3SAndré Almeida return -EFAULT;
276bf69bad3SAndré Almeida
277bf69bad3SAndré Almeida /*
278bf69bad3SAndré Almeida * Since there's no opcode for futex_waitv, use
279bf69bad3SAndré Almeida * FUTEX_WAIT_BITSET that uses absolute timeout as well
280bf69bad3SAndré Almeida */
281bf69bad3SAndré Almeida ret = futex_init_timeout(FUTEX_WAIT_BITSET, flag_init, &ts, &time);
282bf69bad3SAndré Almeida if (ret)
283bf69bad3SAndré Almeida return ret;
284bf69bad3SAndré Almeida
285bf69bad3SAndré Almeida futex_setup_timer(&time, &to, flag_clkid, 0);
286bf69bad3SAndré Almeida }
287bf69bad3SAndré Almeida
288bf69bad3SAndré Almeida futexv = kcalloc(nr_futexes, sizeof(*futexv), GFP_KERNEL);
289*94cd8fa0SMathieu Desnoyers if (!futexv) {
290*94cd8fa0SMathieu Desnoyers ret = -ENOMEM;
291*94cd8fa0SMathieu Desnoyers goto destroy_timer;
292*94cd8fa0SMathieu Desnoyers }
293bf69bad3SAndré Almeida
294bf69bad3SAndré Almeida ret = futex_parse_waitv(futexv, waiters, nr_futexes);
295bf69bad3SAndré Almeida if (!ret)
296bf69bad3SAndré Almeida ret = futex_wait_multiple(futexv, nr_futexes, timeout ? &to : NULL);
297bf69bad3SAndré Almeida
298*94cd8fa0SMathieu Desnoyers kfree(futexv);
299*94cd8fa0SMathieu Desnoyers
300*94cd8fa0SMathieu Desnoyers destroy_timer:
301bf69bad3SAndré Almeida if (timeout) {
302bf69bad3SAndré Almeida hrtimer_cancel(&to.timer);
303bf69bad3SAndré Almeida destroy_hrtimer_on_stack(&to.timer);
304bf69bad3SAndré Almeida }
305bf69bad3SAndré Almeida return ret;
306bf69bad3SAndré Almeida }
307bf69bad3SAndré Almeida
308af8cc960SPeter Zijlstra #ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE2(set_robust_list,struct compat_robust_list_head __user *,head,compat_size_t,len)309af8cc960SPeter Zijlstra COMPAT_SYSCALL_DEFINE2(set_robust_list,
310af8cc960SPeter Zijlstra struct compat_robust_list_head __user *, head,
311af8cc960SPeter Zijlstra compat_size_t, len)
312af8cc960SPeter Zijlstra {
313af8cc960SPeter Zijlstra if (unlikely(len != sizeof(*head)))
314af8cc960SPeter Zijlstra return -EINVAL;
315af8cc960SPeter Zijlstra
316af8cc960SPeter Zijlstra current->compat_robust_list = head;
317af8cc960SPeter Zijlstra
318af8cc960SPeter Zijlstra return 0;
319af8cc960SPeter Zijlstra }
320af8cc960SPeter Zijlstra
COMPAT_SYSCALL_DEFINE3(get_robust_list,int,pid,compat_uptr_t __user *,head_ptr,compat_size_t __user *,len_ptr)321af8cc960SPeter Zijlstra COMPAT_SYSCALL_DEFINE3(get_robust_list, int, pid,
322af8cc960SPeter Zijlstra compat_uptr_t __user *, head_ptr,
323af8cc960SPeter Zijlstra compat_size_t __user *, len_ptr)
324af8cc960SPeter Zijlstra {
325af8cc960SPeter Zijlstra struct compat_robust_list_head __user *head;
326af8cc960SPeter Zijlstra unsigned long ret;
327af8cc960SPeter Zijlstra struct task_struct *p;
328af8cc960SPeter Zijlstra
329af8cc960SPeter Zijlstra rcu_read_lock();
330af8cc960SPeter Zijlstra
331af8cc960SPeter Zijlstra ret = -ESRCH;
332af8cc960SPeter Zijlstra if (!pid)
333af8cc960SPeter Zijlstra p = current;
334af8cc960SPeter Zijlstra else {
335af8cc960SPeter Zijlstra p = find_task_by_vpid(pid);
336af8cc960SPeter Zijlstra if (!p)
337af8cc960SPeter Zijlstra goto err_unlock;
338af8cc960SPeter Zijlstra }
339af8cc960SPeter Zijlstra
340af8cc960SPeter Zijlstra ret = -EPERM;
341af8cc960SPeter Zijlstra if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
342af8cc960SPeter Zijlstra goto err_unlock;
343af8cc960SPeter Zijlstra
344af8cc960SPeter Zijlstra head = p->compat_robust_list;
345af8cc960SPeter Zijlstra rcu_read_unlock();
346af8cc960SPeter Zijlstra
347af8cc960SPeter Zijlstra if (put_user(sizeof(*head), len_ptr))
348af8cc960SPeter Zijlstra return -EFAULT;
349af8cc960SPeter Zijlstra return put_user(ptr_to_compat(head), head_ptr);
350af8cc960SPeter Zijlstra
351af8cc960SPeter Zijlstra err_unlock:
352af8cc960SPeter Zijlstra rcu_read_unlock();
353af8cc960SPeter Zijlstra
354af8cc960SPeter Zijlstra return ret;
355af8cc960SPeter Zijlstra }
356af8cc960SPeter Zijlstra #endif /* CONFIG_COMPAT */
357af8cc960SPeter Zijlstra
358af8cc960SPeter Zijlstra #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)359af8cc960SPeter Zijlstra SYSCALL_DEFINE6(futex_time32, u32 __user *, uaddr, int, op, u32, val,
360af8cc960SPeter Zijlstra const struct old_timespec32 __user *, utime, u32 __user *, uaddr2,
361af8cc960SPeter Zijlstra u32, val3)
362af8cc960SPeter Zijlstra {
363af8cc960SPeter Zijlstra int ret, cmd = op & FUTEX_CMD_MASK;
364af8cc960SPeter Zijlstra ktime_t t, *tp = NULL;
365af8cc960SPeter Zijlstra struct timespec64 ts;
366af8cc960SPeter Zijlstra
367af8cc960SPeter Zijlstra if (utime && futex_cmd_has_timeout(cmd)) {
368af8cc960SPeter Zijlstra if (get_old_timespec32(&ts, utime))
369af8cc960SPeter Zijlstra return -EFAULT;
370af8cc960SPeter Zijlstra ret = futex_init_timeout(cmd, op, &ts, &t);
371af8cc960SPeter Zijlstra if (ret)
372af8cc960SPeter Zijlstra return ret;
373af8cc960SPeter Zijlstra tp = &t;
374af8cc960SPeter Zijlstra }
375af8cc960SPeter Zijlstra
376af8cc960SPeter Zijlstra return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3);
377af8cc960SPeter Zijlstra }
378af8cc960SPeter Zijlstra #endif /* CONFIG_COMPAT_32BIT_TIME */
379af8cc960SPeter Zijlstra
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