1 files changed, 93 insertions, 70 deletions

diff --git a/ipc/sem.c b/ipc/sem.c
index f6c30a85dadf..a39cdc7bf88f 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -36,7 +36,7 @@
  * - two Linux specific semctl() commands: SEM_STAT, SEM_INFO.
  * - undo adjustments at process exit are limited to 0..SEMVMX.
  * - namespace are supported.
- * - SEMMSL, SEMMNS, SEMOPM and SEMMNI can be configured at runtine by writing
+ * - SEMMSL, SEMMNS, SEMOPM and SEMMNI can be configured at runtime by writing
  *   to /proc/sys/kernel/sem.
  * - statistics about the usage are reported in /proc/sysvipc/sem.
  *
@@ -152,7 +152,7 @@ struct sem_undo {
 	struct list_head	list_id;	/* per semaphore array list:
 						 * all undos for one array */
 	int			semid;		/* semaphore set identifier */
-	short			*semadj;	/* array of adjustments */
+	short			semadj[];	/* array of adjustments */
 						/* one per semaphore */
 };
 
@@ -217,6 +217,8 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it);
  * this smp_load_acquire(), this is guaranteed because the smp_load_acquire()
  * is inside a spin_lock() and after a write from 0 to non-zero a
  * spin_lock()+spin_unlock() is done.
+ * To prevent the compiler/cpu temporarily writing 0 to use_global_lock,
+ * READ_ONCE()/WRITE_ONCE() is used.
  *
  * 2) queue.status: (SEM_BARRIER_2)
  * Initialization is done while holding sem_lock(), so no further barrier is
@@ -224,7 +226,7 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it);
  * Setting it to a result code is a RELEASE, this is ensured by both a
  * smp_store_release() (for case a) and while holding sem_lock()
  * (for case b).
- * The AQUIRE when reading the result code without holding sem_lock() is
+ * The ACQUIRE when reading the result code without holding sem_lock() is
  * achieved by using READ_ONCE() + smp_acquire__after_ctrl_dep().
  * (case a above).
  * Reading the result code while holding sem_lock() needs no further barriers,
@@ -342,10 +344,10 @@ static void complexmode_enter(struct sem_array *sma)
 		 * Nothing to do, just reset the
 		 * counter until we return to simple mode.
 		 */
-		sma->use_global_lock = USE_GLOBAL_LOCK_HYSTERESIS;
+		WRITE_ONCE(sma->use_global_lock, USE_GLOBAL_LOCK_HYSTERESIS);
 		return;
 	}
-	sma->use_global_lock = USE_GLOBAL_LOCK_HYSTERESIS;
+	WRITE_ONCE(sma->use_global_lock, USE_GLOBAL_LOCK_HYSTERESIS);
 
 	for (i = 0; i < sma->sem_nsems; i++) {
 		sem = &sma->sems[i];
@@ -371,7 +373,8 @@ static void complexmode_tryleave(struct sem_array *sma)
 		/* See SEM_BARRIER_1 for purpose/pairing */
 		smp_store_release(&sma->use_global_lock, 0);
 	} else {
-		sma->use_global_lock--;
+		WRITE_ONCE(sma->use_global_lock,
+				sma->use_global_lock-1);
 	}
 }
 
@@ -412,7 +415,7 @@ static inline int sem_lock(struct sem_array *sma, struct sembuf *sops,
 	 * Initial check for use_global_lock. Just an optimization,
 	 * no locking, no memory barrier.
 	 */
-	if (!sma->use_global_lock) {
+	if (!READ_ONCE(sma->use_global_lock)) {
 		/*
 		 * It appears that no complex operation is around.
 		 * Acquire the per-semaphore lock.
@@ -511,7 +514,7 @@ static struct sem_array *sem_alloc(size_t nsems)
 	if (nsems > (INT_MAX - sizeof(*sma)) / sizeof(sma->sems[0]))
 		return NULL;
 
-	sma = kvzalloc(struct_size(sma, sems, nsems), GFP_KERNEL);
+	sma = kvzalloc(struct_size(sma, sems, nsems), GFP_KERNEL_ACCOUNT);
 	if (unlikely(!sma))
 		return NULL;
 
@@ -763,7 +766,6 @@ static int perform_atomic_semop(struct sem_array *sma, struct sem_queue *q)
 	for (sop = sops; sop < sops + nsops; sop++) {
 		curr = &sma->sems[sop->sem_num];
 		sem_op = sop->sem_op;
-		result = curr->semval;
 
 		if (sop->sem_flg & SEM_UNDO) {
 			int undo = un->semadj[sop->sem_num] - sem_op;
@@ -784,12 +786,14 @@ would_block:
 static inline void wake_up_sem_queue_prepare(struct sem_queue *q, int error,
 					     struct wake_q_head *wake_q)
 {
-	get_task_struct(q->sleeper);
+	struct task_struct *sleeper;
+
+	sleeper = get_task_struct(q->sleeper);
 
-	/* see SEM_BARRIER_2 for purpuse/pairing */
+	/* see SEM_BARRIER_2 for purpose/pairing */
 	smp_store_release(&q->status, error);
 
-	wake_q_add_safe(wake_q, q->sleeper);
+	wake_q_add_safe(wake_q, sleeper);
 }
 
 static void unlink_queue(struct sem_array *sma, struct sem_queue *q)
@@ -821,7 +825,7 @@ static inline int check_restart(struct sem_array *sma, struct sem_queue *q)
 
 	/* It is impossible that someone waits for the new value:
 	 * - complex operations always restart.
-	 * - wait-for-zero are handled seperately.
+	 * - wait-for-zero are handled separately.
 	 * - q is a previously sleeping simple operation that
 	 *   altered the array. It must be a decrement, because
 	 *   simple increments never sleep.
@@ -1046,7 +1050,7 @@ static void do_smart_update(struct sem_array *sma, struct sembuf *sops, int nsop
 			 * - No complex ops, thus all sleeping ops are
 			 *   decrease.
 			 * - if we decreased the value, then any sleeping
-			 *   semaphore ops wont be able to run: If the
+			 *   semaphore ops won't be able to run: If the
 			 *   previous value was too small, then the new
 			 *   value will be too small, too.
 			 */
@@ -1152,7 +1156,7 @@ static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
 		un->semid = -1;
 		list_del_rcu(&un->list_proc);
 		spin_unlock(&un->ulp->lock);
-		kfree_rcu(un, rcu);
+		kvfree_rcu(un, rcu);
 	}
 
 	/* Wake up all pending processes and let them fail with EIDRM. */
@@ -1425,7 +1429,6 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
 	if (err)
 		goto out_rcu_wakeup;
 
-	err = -EACCES;
 	switch (cmd) {
 	case GETALL:
 	{
@@ -1850,7 +1853,7 @@ static inline int get_undo_list(struct sem_undo_list **undo_listp)
 
 	undo_list = current->sysvsem.undo_list;
 	if (!undo_list) {
-		undo_list = kzalloc(sizeof(*undo_list), GFP_KERNEL);
+		undo_list = kzalloc(sizeof(*undo_list), GFP_KERNEL_ACCOUNT);
 		if (undo_list == NULL)
 			return -ENOMEM;
 		spin_lock_init(&undo_list->lock);
@@ -1935,7 +1938,7 @@ static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid)
 	rcu_read_unlock();
 
 	/* step 2: allocate new undo structure */
-	new = kzalloc(sizeof(struct sem_undo) + sizeof(short)*nsems, GFP_KERNEL);
+	new = kvzalloc(struct_size(new, semadj, nsems), GFP_KERNEL_ACCOUNT);
 	if (!new) {
 		ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
 		return ERR_PTR(-ENOMEM);
@@ -1947,7 +1950,7 @@ static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid)
 	if (!ipc_valid_object(&sma->sem_perm)) {
 		sem_unlock(sma, -1);
 		rcu_read_unlock();
-		kfree(new);
+		kvfree(new);
 		un = ERR_PTR(-EIDRM);
 		goto out;
 	}
@@ -1958,11 +1961,11 @@ static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid)
 	 */
 	un = lookup_undo(ulp, semid);
 	if (un) {
-		kfree(new);
+		spin_unlock(&ulp->lock);
+		kvfree(new);
 		goto success;
 	}
 	/* step 5: initialize & link new undo structure */
-	new->semadj = (short *) &new[1];
 	new->ulp = ulp;
 	new->semid = semid;
 	assert_spin_locked(&ulp->lock);
@@ -1970,54 +1973,42 @@ static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid)
 	ipc_assert_locked_object(&sma->sem_perm);
 	list_add(&new->list_id, &sma->list_id);
 	un = new;
-
-success:
 	spin_unlock(&ulp->lock);
+success:
 	sem_unlock(sma, -1);
 out:
 	return un;
 }
 
-static long do_semtimedop(int semid, struct sembuf __user *tsops,
-		unsigned nsops, const struct timespec64 *timeout)
+long __do_semtimedop(int semid, struct sembuf *sops,
+		unsigned nsops, const struct timespec64 *timeout,
+		struct ipc_namespace *ns)
 {
 	int error = -EINVAL;
 	struct sem_array *sma;
-	struct sembuf fast_sops[SEMOPM_FAST];
-	struct sembuf *sops = fast_sops, *sop;
+	struct sembuf *sop;
 	struct sem_undo *un;
 	int max, locknum;
 	bool undos = false, alter = false, dupsop = false;
 	struct sem_queue queue;
-	unsigned long dup = 0, jiffies_left = 0;
-	struct ipc_namespace *ns;
-
-	ns = current->nsproxy->ipc_ns;
+	unsigned long dup = 0;
+	ktime_t expires, *exp = NULL;
+	bool timed_out = false;
 
 	if (nsops < 1 || semid < 0)
 		return -EINVAL;
 	if (nsops > ns->sc_semopm)
 		return -E2BIG;
-	if (nsops > SEMOPM_FAST) {
-		sops = kvmalloc_array(nsops, sizeof(*sops), GFP_KERNEL);
-		if (sops == NULL)
-			return -ENOMEM;
-	}
-
-	if (copy_from_user(sops, tsops, nsops * sizeof(*tsops))) {
-		error =  -EFAULT;
-		goto out_free;
-	}
 
 	if (timeout) {
-		if (timeout->tv_sec < 0 || timeout->tv_nsec < 0 ||
-			timeout->tv_nsec >= 1000000000L) {
-			error = -EINVAL;
-			goto out_free;
-		}
-		jiffies_left = timespec64_to_jiffies(timeout);
+		if (!timespec64_valid(timeout))
+			return -EINVAL;
+		expires = ktime_add_safe(ktime_get(),
+				timespec64_to_ktime(*timeout));
+		exp = &expires;
 	}
 
+
 	max = 0;
 	for (sop = sops; sop < sops + nsops; sop++) {
 		unsigned long mask = 1ULL << ((sop->sem_num) % BITS_PER_LONG);
@@ -2046,7 +2037,7 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops,
 		un = find_alloc_undo(ns, semid);
 		if (IS_ERR(un)) {
 			error = PTR_ERR(un);
-			goto out_free;
+			goto out;
 		}
 	} else {
 		un = NULL;
@@ -2057,25 +2048,25 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops,
 	if (IS_ERR(sma)) {
 		rcu_read_unlock();
 		error = PTR_ERR(sma);
-		goto out_free;
+		goto out;
 	}
 
 	error = -EFBIG;
 	if (max >= sma->sem_nsems) {
 		rcu_read_unlock();
-		goto out_free;
+		goto out;
 	}
 
 	error = -EACCES;
 	if (ipcperms(ns, &sma->sem_perm, alter ? S_IWUGO : S_IRUGO)) {
 		rcu_read_unlock();
-		goto out_free;
+		goto out;
 	}
 
 	error = security_sem_semop(&sma->sem_perm, sops, nsops, alter);
 	if (error) {
 		rcu_read_unlock();
-		goto out_free;
+		goto out;
 	}
 
 	error = -EIDRM;
@@ -2089,7 +2080,7 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops,
 	 * entangled here and why it's RMID race safe on comments at sem_lock()
 	 */
 	if (!ipc_valid_object(&sma->sem_perm))
-		goto out_unlock_free;
+		goto out_unlock;
 	/*
 	 * semid identifiers are not unique - find_alloc_undo may have
 	 * allocated an undo structure, it was invalidated by an RMID
@@ -2098,7 +2089,7 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops,
 	 * "un" itself is guaranteed by rcu.
 	 */
 	if (un && un->semid == -1)
-		goto out_unlock_free;
+		goto out_unlock;
 
 	queue.sops = sops;
 	queue.nsops = nsops;
@@ -2108,7 +2099,7 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops,
 	queue.dupsop = dupsop;
 
 	error = perform_atomic_semop(sma, &queue);
-	if (error == 0) { /* non-blocking succesfull path */
+	if (error == 0) { /* non-blocking successful path */
 		DEFINE_WAKE_Q(wake_q);
 
 		/*
@@ -2124,10 +2115,10 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops,
 		rcu_read_unlock();
 		wake_up_q(&wake_q);
 
-		goto out_free;
+		goto out;
 	}
 	if (error < 0) /* non-blocking error path */
-		goto out_unlock_free;
+		goto out_unlock;
 
 	/*
 	 * We need to sleep on this operation, so we put the current
@@ -2172,10 +2163,8 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops,
 		sem_unlock(sma, locknum);
 		rcu_read_unlock();
 
-		if (timeout)
-			jiffies_left = schedule_timeout(jiffies_left);
-		else
-			schedule();
+		timed_out = !schedule_hrtimeout_range(exp,
+				current->timer_slack_ns, HRTIMER_MODE_ABS);
 
 		/*
 		 * fastpath: the semop has completed, either successfully or
@@ -2188,18 +2177,19 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops,
 		 * scenarios where we were awakened externally, during the
 		 * window between wake_q_add() and wake_up_q().
 		 */
+		rcu_read_lock();
 		error = READ_ONCE(queue.status);
 		if (error != -EINTR) {
 			/* see SEM_BARRIER_2 for purpose/pairing */
 			smp_acquire__after_ctrl_dep();
-			goto out_free;
+			rcu_read_unlock();
+			goto out;
 		}
 
-		rcu_read_lock();
 		locknum = sem_lock(sma, sops, nsops);
 
 		if (!ipc_valid_object(&sma->sem_perm))
-			goto out_unlock_free;
+			goto out_unlock;
 
 		/*
 		 * No necessity for any barrier: We are protect by sem_lock()
@@ -2211,24 +2201,56 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops,
 		 * Leave without unlink_queue(), but with sem_unlock().
 		 */
 		if (error != -EINTR)
-			goto out_unlock_free;
+			goto out_unlock;
 
 		/*
 		 * If an interrupt occurred we have to clean up the queue.
 		 */
-		if (timeout && jiffies_left == 0)
+		if (timed_out)
 			error = -EAGAIN;
 	} while (error == -EINTR && !signal_pending(current)); /* spurious */
 
 	unlink_queue(sma, &queue);
 
-out_unlock_free:
+out_unlock:
 	sem_unlock(sma, locknum);
 	rcu_read_unlock();
+out:
+	return error;
+}
+
+static long do_semtimedop(int semid, struct sembuf __user *tsops,
+		unsigned nsops, const struct timespec64 *timeout)
+{
+	struct sembuf fast_sops[SEMOPM_FAST];
+	struct sembuf *sops = fast_sops;
+	struct ipc_namespace *ns;
+	int ret;
+
+	ns = current->nsproxy->ipc_ns;
+	if (nsops > ns->sc_semopm)
+		return -E2BIG;
+	if (nsops < 1)
+		return -EINVAL;
+
+	if (nsops > SEMOPM_FAST) {
+		sops = kvmalloc_array(nsops, sizeof(*sops), GFP_KERNEL);
+		if (sops == NULL)
+			return -ENOMEM;
+	}
+
+	if (copy_from_user(sops, tsops, nsops * sizeof(*tsops))) {
+		ret =  -EFAULT;
+		goto out_free;
+	}
+
+	ret = __do_semtimedop(semid, sops, nsops, timeout, ns);
+
 out_free:
 	if (sops != fast_sops)
 		kvfree(sops);
-	return error;
+
+	return ret;
 }
 
 long ksys_semtimedop(int semid, struct sembuf __user *tsops,
@@ -2418,7 +2440,7 @@ void exit_sem(struct task_struct *tsk)
 		rcu_read_unlock();
 		wake_up_q(&wake_q);
 
-		kfree_rcu(un, rcu);
+		kvfree_rcu(un, rcu);
 	}
 	kfree(ulp);
 }
@@ -2433,7 +2455,8 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it)
 
 	/*
 	 * The proc interface isn't aware of sem_lock(), it calls
-	 * ipc_lock_object() directly (in sysvipc_find_ipc).
+	 * ipc_lock_object(), i.e. spin_lock(&sma->sem_perm.lock).
+	 * (in sysvipc_find_ipc)
 	 * In order to stay compatible with sem_lock(), we must
 	 * enter / leave complex_mode.
 	 */