1 files changed, 320 insertions, 60 deletions

diff --git a/kernel/futex.c b/kernel/futex.c
index 3e2de8fc1891..c3b73b0311bc 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -44,6 +44,7 @@
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
+#include <linux/compat.h>
 #include <linux/slab.h>
 #include <linux/poll.h>
 #include <linux/fs.h>
@@ -65,8 +66,9 @@
 #include <linux/sched/mm.h>
 #include <linux/hugetlb.h>
 #include <linux/freezer.h>
-#include <linux/bootmem.h>
+#include <linux/memblock.h>
 #include <linux/fault-inject.h>
+#include <linux/refcount.h>
 
 #include <asm/futex.h>
 
@@ -173,8 +175,10 @@
  * double_lock_hb() and double_unlock_hb(), respectively.
  */
 
-#ifndef CONFIG_HAVE_FUTEX_CMPXCHG
-int __read_mostly futex_cmpxchg_enabled;
+#ifdef CONFIG_HAVE_FUTEX_CMPXCHG
+#define futex_cmpxchg_enabled 1
+#else
+static int  __read_mostly futex_cmpxchg_enabled;
 #endif
 
 /*
@@ -209,7 +213,7 @@ struct futex_pi_state {
 	struct rt_mutex pi_mutex;
 
 	struct task_struct *owner;
-	atomic_t refcount;
+	refcount_t refcount;
 
 	union futex_key key;
 } __randomize_layout;
@@ -318,12 +322,8 @@ static int __init fail_futex_debugfs(void)
 	if (IS_ERR(dir))
 		return PTR_ERR(dir);
 
-	if (!debugfs_create_bool("ignore-private", mode, dir,
-				 &fail_futex.ignore_private)) {
-		debugfs_remove_recursive(dir);
-		return -ENOMEM;
-	}
-
+	debugfs_create_bool("ignore-private", mode, dir,
+			    &fail_futex.ignore_private);
 	return 0;
 }
 
@@ -478,13 +478,18 @@ static void drop_futex_key_refs(union futex_key *key)
 	}
 }
 
+enum futex_access {
+	FUTEX_READ,
+	FUTEX_WRITE
+};
+
 /**
  * get_futex_key() - Get parameters which are the keys for a futex
  * @uaddr:	virtual address of the futex
  * @fshared:	0 for a PROCESS_PRIVATE futex, 1 for PROCESS_SHARED
  * @key:	address where result is stored.
- * @rw:		mapping needs to be read/write (values: VERIFY_READ,
- *              VERIFY_WRITE)
+ * @rw:		mapping needs to be read/write (values: FUTEX_READ,
+ *              FUTEX_WRITE)
  *
  * Return: a negative error code or 0
  *
@@ -497,7 +502,7 @@ static void drop_futex_key_refs(union futex_key *key)
  * lock_page() might sleep, the caller should not hold a spinlock.
  */
 static int
-get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
+get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, enum futex_access rw)
 {
 	unsigned long address = (unsigned long)uaddr;
 	struct mm_struct *mm = current->mm;
@@ -513,7 +518,7 @@ get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
 		return -EINVAL;
 	address -= key->both.offset;
 
-	if (unlikely(!access_ok(rw, uaddr, sizeof(u32))))
+	if (unlikely(!access_ok(uaddr, sizeof(u32))))
 		return -EFAULT;
 
 	if (unlikely(should_fail_futex(fshared)))
@@ -543,7 +548,7 @@ again:
 	 * If write access is not required (eg. FUTEX_WAIT), try
 	 * and get read-only access.
 	 */
-	if (err == -EFAULT && rw == VERIFY_READ) {
+	if (err == -EFAULT && rw == FUTEX_READ) {
 		err = get_user_pages_fast(address, 1, 0, &page);
 		ro = 1;
 	}
@@ -795,7 +800,7 @@ static int refill_pi_state_cache(void)
 	INIT_LIST_HEAD(&pi_state->list);
 	/* pi_mutex gets initialized later */
 	pi_state->owner = NULL;
-	atomic_set(&pi_state->refcount, 1);
+	refcount_set(&pi_state->refcount, 1);
 	pi_state->key = FUTEX_KEY_INIT;
 
 	current->pi_state_cache = pi_state;
@@ -815,7 +820,7 @@ static struct futex_pi_state *alloc_pi_state(void)
 
 static void get_pi_state(struct futex_pi_state *pi_state)
 {
-	WARN_ON_ONCE(!atomic_inc_not_zero(&pi_state->refcount));
+	WARN_ON_ONCE(!refcount_inc_not_zero(&pi_state->refcount));
 }
 
 /*
@@ -827,7 +832,7 @@ static void put_pi_state(struct futex_pi_state *pi_state)
 	if (!pi_state)
 		return;
 
-	if (!atomic_dec_and_test(&pi_state->refcount))
+	if (!refcount_dec_and_test(&pi_state->refcount))
 		return;
 
 	/*
@@ -857,7 +862,7 @@ static void put_pi_state(struct futex_pi_state *pi_state)
 		 * refcount is at 0 - put it back to 1.
 		 */
 		pi_state->owner = NULL;
-		atomic_set(&pi_state->refcount, 1);
+		refcount_set(&pi_state->refcount, 1);
 		current->pi_state_cache = pi_state;
 	}
 }
@@ -900,7 +905,7 @@ void exit_pi_state_list(struct task_struct *curr)
 		 * In that case; drop the locks to let put_pi_state() make
 		 * progress and retry the loop.
 		 */
-		if (!atomic_inc_not_zero(&pi_state->refcount)) {
+		if (!refcount_inc_not_zero(&pi_state->refcount)) {
 			raw_spin_unlock_irq(&curr->pi_lock);
 			cpu_relax();
 			raw_spin_lock_irq(&curr->pi_lock);
@@ -1056,7 +1061,7 @@ static int attach_to_pi_state(u32 __user *uaddr, u32 uval,
 	 * and futex_wait_requeue_pi() as it cannot go to 0 and consequently
 	 * free pi_state before we can take a reference ourselves.
 	 */
-	WARN_ON(!atomic_read(&pi_state->refcount));
+	WARN_ON(!refcount_read(&pi_state->refcount));
 
 	/*
 	 * Now that we have a pi_state, we can acquire wait_lock
@@ -1148,11 +1153,65 @@ out_error:
 	return ret;
 }
 
+static int handle_exit_race(u32 __user *uaddr, u32 uval,
+			    struct task_struct *tsk)
+{
+	u32 uval2;
+
+	/*
+	 * If PF_EXITPIDONE is not yet set, then try again.
+	 */
+	if (tsk && !(tsk->flags & PF_EXITPIDONE))
+		return -EAGAIN;
+
+	/*
+	 * Reread the user space value to handle the following situation:
+	 *
+	 * CPU0				CPU1
+	 *
+	 * sys_exit()			sys_futex()
+	 *  do_exit()			 futex_lock_pi()
+	 *                                futex_lock_pi_atomic()
+	 *   exit_signals(tsk)		    No waiters:
+	 *    tsk->flags |= PF_EXITING;	    *uaddr == 0x00000PID
+	 *  mm_release(tsk)		    Set waiter bit
+	 *   exit_robust_list(tsk) {	    *uaddr = 0x80000PID;
+	 *      Set owner died		    attach_to_pi_owner() {
+	 *    *uaddr = 0xC0000000;	     tsk = get_task(PID);
+	 *   }				     if (!tsk->flags & PF_EXITING) {
+	 *  ...				       attach();
+	 *  tsk->flags |= PF_EXITPIDONE;     } else {
+	 *				       if (!(tsk->flags & PF_EXITPIDONE))
+	 *				         return -EAGAIN;
+	 *				       return -ESRCH; <--- FAIL
+	 *				     }
+	 *
+	 * Returning ESRCH unconditionally is wrong here because the
+	 * user space value has been changed by the exiting task.
+	 *
+	 * The same logic applies to the case where the exiting task is
+	 * already gone.
+	 */
+	if (get_futex_value_locked(&uval2, uaddr))
+		return -EFAULT;
+
+	/* If the user space value has changed, try again. */
+	if (uval2 != uval)
+		return -EAGAIN;
+
+	/*
+	 * The exiting task did not have a robust list, the robust list was
+	 * corrupted or the user space value in *uaddr is simply bogus.
+	 * Give up and tell user space.
+	 */
+	return -ESRCH;
+}
+
 /*
  * Lookup the task for the TID provided from user space and attach to
  * it after doing proper sanity checks.
  */
-static int attach_to_pi_owner(u32 uval, union futex_key *key,
+static int attach_to_pi_owner(u32 __user *uaddr, u32 uval, union futex_key *key,
 			      struct futex_pi_state **ps)
 {
 	pid_t pid = uval & FUTEX_TID_MASK;
@@ -1162,12 +1221,15 @@ static int attach_to_pi_owner(u32 uval, union futex_key *key,
 	/*
 	 * We are the first waiter - try to look up the real owner and attach
 	 * the new pi_state to it, but bail out when TID = 0 [1]
+	 *
+	 * The !pid check is paranoid. None of the call sites should end up
+	 * with pid == 0, but better safe than sorry. Let the caller retry
 	 */
 	if (!pid)
-		return -ESRCH;
+		return -EAGAIN;
 	p = find_get_task_by_vpid(pid);
 	if (!p)
-		return -ESRCH;
+		return handle_exit_race(uaddr, uval, NULL);
 
 	if (unlikely(p->flags & PF_KTHREAD)) {
 		put_task_struct(p);
@@ -1187,7 +1249,7 @@ static int attach_to_pi_owner(u32 uval, union futex_key *key,
 		 * set, we know that the task has finished the
 		 * cleanup:
 		 */
-		int ret = (p->flags & PF_EXITPIDONE) ? -ESRCH : -EAGAIN;
+		int ret = handle_exit_race(uaddr, uval, p);
 
 		raw_spin_unlock_irq(&p->pi_lock);
 		put_task_struct(p);
@@ -1244,7 +1306,7 @@ static int lookup_pi_state(u32 __user *uaddr, u32 uval,
 	 * We are the first waiter - try to look up the owner based on
 	 * @uval and attach to it.
 	 */
-	return attach_to_pi_owner(uval, key, ps);
+	return attach_to_pi_owner(uaddr, uval, key, ps);
 }
 
 static int lock_pi_update_atomic(u32 __user *uaddr, u32 uval, u32 newval)
@@ -1352,7 +1414,7 @@ static int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb,
 	 * attach to the owner. If that fails, no harm done, we only
 	 * set the FUTEX_WAITERS bit in the user space variable.
 	 */
-	return attach_to_pi_owner(uval, key, ps);
+	return attach_to_pi_owner(uaddr, newval, key, ps);
 }
 
 /**
@@ -1387,11 +1449,7 @@ static void mark_wake_futex(struct wake_q_head *wake_q, struct futex_q *q)
 	if (WARN(q->pi_state || q->rt_waiter, "refusing to wake PI futex\n"))
 		return;
 
-	/*
-	 * Queue the task for later wakeup for after we've released
-	 * the hb->lock. wake_q_add() grabs reference to p.
-	 */
-	wake_q_add(wake_q, p);
+	get_task_struct(p);
 	__unqueue_futex(q);
 	/*
 	 * The waiting task can free the futex_q as soon as q->lock_ptr = NULL
@@ -1401,6 +1459,12 @@ static void mark_wake_futex(struct wake_q_head *wake_q, struct futex_q *q)
 	 * plist_del in __unqueue_futex().
 	 */
 	smp_store_release(&q->lock_ptr, NULL);
+
+	/*
+	 * Queue the task for later wakeup for after we've released
+	 * the hb->lock. wake_q_add() grabs reference to p.
+	 */
+	wake_q_add_safe(wake_q, p);
 }
 
 /*
@@ -1523,7 +1587,7 @@ futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset)
 	if (!bitset)
 		return -EINVAL;
 
-	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key, VERIFY_READ);
+	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key, FUTEX_READ);
 	if (unlikely(ret != 0))
 		goto out;
 
@@ -1582,7 +1646,7 @@ static int futex_atomic_op_inuser(unsigned int encoded_op, u32 __user *uaddr)
 		oparg = 1 << oparg;
 	}
 
-	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
+	if (!access_ok(uaddr, sizeof(u32)))
 		return -EFAULT;
 
 	ret = arch_futex_atomic_op_inuser(op, oparg, &oldval, uaddr);
@@ -1622,10 +1686,10 @@ futex_wake_op(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2,
 	DEFINE_WAKE_Q(wake_q);
 
 retry:
-	ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, VERIFY_READ);
+	ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, FUTEX_READ);
 	if (unlikely(ret != 0))
 		goto out;
-	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, VERIFY_WRITE);
+	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, FUTEX_WRITE);
 	if (unlikely(ret != 0))
 		goto out_put_key1;
 
@@ -1901,11 +1965,11 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
 	}
 
 retry:
-	ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, VERIFY_READ);
+	ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, FUTEX_READ);
 	if (unlikely(ret != 0))
 		goto out;
 	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2,
-			    requeue_pi ? VERIFY_WRITE : VERIFY_READ);
+			    requeue_pi ? FUTEX_WRITE : FUTEX_READ);
 	if (unlikely(ret != 0))
 		goto out_put_key1;
 
@@ -2153,11 +2217,11 @@ static inline struct futex_hash_bucket *queue_lock(struct futex_q *q)
 	 * decrement the counter at queue_unlock() when some error has
 	 * occurred and we don't end up adding the task to the list.
 	 */
-	hb_waiters_inc(hb);
+	hb_waiters_inc(hb); /* implies smp_mb(); (A) */
 
 	q->lock_ptr = &hb->lock;
 
-	spin_lock(&hb->lock); /* implies smp_mb(); (A) */
+	spin_lock(&hb->lock);
 	return hb;
 }
 
@@ -2574,7 +2638,7 @@ static int futex_wait_setup(u32 __user *uaddr, u32 val, unsigned int flags,
 	 * while the syscall executes.
 	 */
 retry:
-	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q->key, VERIFY_READ);
+	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q->key, FUTEX_READ);
 	if (unlikely(ret != 0))
 		return ret;
 
@@ -2733,7 +2797,7 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
 	}
 
 retry:
-	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q.key, VERIFY_WRITE);
+	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q.key, FUTEX_WRITE);
 	if (unlikely(ret != 0))
 		goto out;
 
@@ -2793,35 +2857,39 @@ retry_private:
 	 * and BUG when futex_unlock_pi() interleaves with this.
 	 *
 	 * Therefore acquire wait_lock while holding hb->lock, but drop the
-	 * latter before calling rt_mutex_start_proxy_lock(). This still fully
-	 * serializes against futex_unlock_pi() as that does the exact same
-	 * lock handoff sequence.
+	 * latter before calling __rt_mutex_start_proxy_lock(). This
+	 * interleaves with futex_unlock_pi() -- which does a similar lock
+	 * handoff -- such that the latter can observe the futex_q::pi_state
+	 * before __rt_mutex_start_proxy_lock() is done.
 	 */
 	raw_spin_lock_irq(&q.pi_state->pi_mutex.wait_lock);
 	spin_unlock(q.lock_ptr);
+	/*
+	 * __rt_mutex_start_proxy_lock() unconditionally enqueues the @rt_waiter
+	 * such that futex_unlock_pi() is guaranteed to observe the waiter when
+	 * it sees the futex_q::pi_state.
+	 */
 	ret = __rt_mutex_start_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter, current);
 	raw_spin_unlock_irq(&q.pi_state->pi_mutex.wait_lock);
 
 	if (ret) {
 		if (ret == 1)
 			ret = 0;
-
-		spin_lock(q.lock_ptr);
-		goto no_block;
+		goto cleanup;
 	}
 
-
 	if (unlikely(to))
 		hrtimer_start_expires(&to->timer, HRTIMER_MODE_ABS);
 
 	ret = rt_mutex_wait_proxy_lock(&q.pi_state->pi_mutex, to, &rt_waiter);
 
+cleanup:
 	spin_lock(q.lock_ptr);
 	/*
-	 * If we failed to acquire the lock (signal/timeout), we must
+	 * If we failed to acquire the lock (deadlock/signal/timeout), we must
 	 * first acquire the hb->lock before removing the lock from the
-	 * rt_mutex waitqueue, such that we can keep the hb and rt_mutex
-	 * wait lists consistent.
+	 * rt_mutex waitqueue, such that we can keep the hb and rt_mutex wait
+	 * lists consistent.
 	 *
 	 * In particular; it is important that futex_unlock_pi() can not
 	 * observe this inconsistency.
@@ -2912,7 +2980,7 @@ retry:
 	if ((uval & FUTEX_TID_MASK) != vpid)
 		return -EPERM;
 
-	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key, VERIFY_WRITE);
+	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key, FUTEX_WRITE);
 	if (ret)
 		return ret;
 
@@ -2945,6 +3013,10 @@ retry:
 		 * there is no point where we hold neither; and therefore
 		 * wake_futex_pi() must observe a state consistent with what we
 		 * observed.
+		 *
+		 * In particular; this forces __rt_mutex_start_proxy() to
+		 * complete such that we're guaranteed to observe the
+		 * rt_waiter. Also see the WARN in wake_futex_pi().
 		 */
 		raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
 		spin_unlock(&hb->lock);
@@ -3139,7 +3211,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
 	 */
 	rt_mutex_init_waiter(&rt_waiter);
 
-	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, VERIFY_WRITE);
+	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, FUTEX_WRITE);
 	if (unlikely(ret != 0))
 		goto out;
 
@@ -3360,7 +3432,7 @@ err_unlock:
  * Process a futex-list entry, check whether it's owned by the
  * dying task, and do notification if so:
  */
-int handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi)
+static int handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi)
 {
 	u32 uval, uninitialized_var(nval), mval;
 
@@ -3555,10 +3627,10 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
 
 
 SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
-		struct timespec __user *, utime, u32 __user *, uaddr2,
+		struct __kernel_timespec __user *, utime, u32 __user *, uaddr2,
 		u32, val3)
 {
-	struct timespec ts;
+	struct timespec64 ts;
 	ktime_t t, *tp = NULL;
 	u32 val2 = 0;
 	int cmd = op & FUTEX_CMD_MASK;
@@ -3568,12 +3640,12 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
 		      cmd == FUTEX_WAIT_REQUEUE_PI)) {
 		if (unlikely(should_fail_futex(!(op & FUTEX_PRIVATE_FLAG))))
 			return -EFAULT;
-		if (copy_from_user(&ts, utime, sizeof(ts)) != 0)
+		if (get_timespec64(&ts, utime))
 			return -EFAULT;
-		if (!timespec_valid(&ts))
+		if (!timespec64_valid(&ts))
 			return -EINVAL;
 
-		t = timespec_to_ktime(ts);
+		t = timespec64_to_ktime(ts);
 		if (cmd == FUTEX_WAIT)
 			t = ktime_add_safe(ktime_get(), t);
 		tp = &t;
@@ -3589,6 +3661,194 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
 	return do_futex(uaddr, op, val, tp, uaddr2, val2, val3);
 }
 
+#ifdef CONFIG_COMPAT
+/*
+ * Fetch a robust-list pointer. Bit 0 signals PI futexes:
+ */
+static inline int
+compat_fetch_robust_entry(compat_uptr_t *uentry, struct robust_list __user **entry,
+		   compat_uptr_t __user *head, unsigned int *pi)
+{
+	if (get_user(*uentry, head))
+		return -EFAULT;
+
+	*entry = compat_ptr((*uentry) & ~1);
+	*pi = (unsigned int)(*uentry) & 1;
+
+	return 0;
+}
+
+static void __user *futex_uaddr(struct robust_list __user *entry,
+				compat_long_t futex_offset)
+{
+	compat_uptr_t base = ptr_to_compat(entry);
+	void __user *uaddr = compat_ptr(base + futex_offset);
+
+	return uaddr;
+}
+
+/*
+ * Walk curr->robust_list (very carefully, it's a userspace list!)
+ * and mark any locks found there dead, and notify any waiters.
+ *
+ * We silently return on any sign of list-walking problem.
+ */
+void compat_exit_robust_list(struct task_struct *curr)
+{
+	struct compat_robust_list_head __user *head = curr->compat_robust_list;
+	struct robust_list __user *entry, *next_entry, *pending;
+	unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
+	unsigned int uninitialized_var(next_pi);
+	compat_uptr_t uentry, next_uentry, upending;
+	compat_long_t futex_offset;
+	int rc;
+
+	if (!futex_cmpxchg_enabled)
+		return;
+
+	/*
+	 * Fetch the list head (which was registered earlier, via
+	 * sys_set_robust_list()):
+	 */
+	if (compat_fetch_robust_entry(&uentry, &entry, &head->list.next, &pi))
+		return;
+	/*
+	 * Fetch the relative futex offset:
+	 */
+	if (get_user(futex_offset, &head->futex_offset))
+		return;
+	/*
+	 * Fetch any possibly pending lock-add first, and handle it
+	 * if it exists:
+	 */
+	if (compat_fetch_robust_entry(&upending, &pending,
+			       &head->list_op_pending, &pip))
+		return;
+
+	next_entry = NULL;	/* avoid warning with gcc */
+	while (entry != (struct robust_list __user *) &head->list) {
+		/*
+		 * Fetch the next entry in the list before calling
+		 * handle_futex_death:
+		 */
+		rc = compat_fetch_robust_entry(&next_uentry, &next_entry,
+			(compat_uptr_t __user *)&entry->next, &next_pi);
+		/*
+		 * A pending lock might already be on the list, so
+		 * dont process it twice:
+		 */
+		if (entry != pending) {
+			void __user *uaddr = futex_uaddr(entry, futex_offset);
+
+			if (handle_futex_death(uaddr, curr, pi))
+				return;
+		}
+		if (rc)
+			return;
+		uentry = next_uentry;
+		entry = next_entry;
+		pi = next_pi;
+		/*
+		 * Avoid excessively long or circular lists:
+		 */
+		if (!--limit)
+			break;
+
+		cond_resched();
+	}
+	if (pending) {
+		void __user *uaddr = futex_uaddr(pending, futex_offset);
+
+		handle_futex_death(uaddr, curr, pip);
+	}
+}
+
+COMPAT_SYSCALL_DEFINE2(set_robust_list,
+		struct compat_robust_list_head __user *, head,
+		compat_size_t, len)
+{
+	if (!futex_cmpxchg_enabled)
+		return -ENOSYS;
+
+	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;
+
+	if (!futex_cmpxchg_enabled)
+		return -ENOSYS;
+
+	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,
+		struct old_timespec32 __user *, utime, u32 __user *, uaddr2,
+		u32, val3)
+{
+	struct timespec64 ts;
+	ktime_t t, *tp = NULL;
+	int val2 = 0;
+	int cmd = op & FUTEX_CMD_MASK;
+
+	if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI ||
+		      cmd == FUTEX_WAIT_BITSET ||
+		      cmd == FUTEX_WAIT_REQUEUE_PI)) {
+		if (get_old_timespec32(&ts, utime))
+			return -EFAULT;
+		if (!timespec64_valid(&ts))
+			return -EINVAL;
+
+		t = timespec64_to_ktime(ts);
+		if (cmd == FUTEX_WAIT)
+			t = ktime_add_safe(ktime_get(), t);
+		tp = &t;
+	}
+	if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE ||
+	    cmd == FUTEX_CMP_REQUEUE_PI || cmd == FUTEX_WAKE_OP)
+		val2 = (int) (unsigned long) utime;
+
+	return do_futex(uaddr, op, val, tp, uaddr2, val2, val3);
+}
+#endif /* CONFIG_COMPAT_32BIT_TIME */
+
 static void __init futex_detect_cmpxchg(void)
 {
 #ifndef CONFIG_HAVE_FUTEX_CMPXCHG