Merge tag 'v4.19.50-rt22' into toradex_4.19.y-rt

Linux 4.19.50-rt22

1 files changed, 34 insertions, 14 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 8c1abcba4cbd..78d34e0306e0 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -599,13 +599,18 @@ static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
 static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
 {
 	struct tun_prog *prog;
+	u32 numqueues;
 	u16 ret = 0;
 
+	numqueues = READ_ONCE(tun->numqueues);
+	if (!numqueues)
+		return 0;
+
 	prog = rcu_dereference(tun->steering_prog);
 	if (prog)
 		ret = bpf_prog_run_clear_cb(prog->prog, skb);
 
-	return ret % tun->numqueues;
+	return ret % numqueues;
 }
 
 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
@@ -703,6 +708,8 @@ static void __tun_detach(struct tun_file *tfile, bool clean)
 				   tun->tfiles[tun->numqueues - 1]);
 		ntfile = rtnl_dereference(tun->tfiles[index]);
 		ntfile->queue_index = index;
+		rcu_assign_pointer(tun->tfiles[tun->numqueues - 1],
+				   NULL);
 
 		--tun->numqueues;
 		if (clean) {
@@ -859,10 +866,6 @@ static int tun_attach(struct tun_struct *tun, struct file *file,
 		err = 0;
 	}
 
-	rcu_assign_pointer(tfile->tun, tun);
-	rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
-	tun->numqueues++;
-
 	if (tfile->detached) {
 		tun_enable_queue(tfile);
 	} else {
@@ -870,12 +873,18 @@ static int tun_attach(struct tun_struct *tun, struct file *file,
 		tun_napi_init(tun, tfile, napi, napi_frags);
 	}
 
-	tun_set_real_num_queues(tun);
-
 	/* device is allowed to go away first, so no need to hold extra
 	 * refcnt.
 	 */
 
+	/* Publish tfile->tun and tun->tfiles only after we've fully
+	 * initialized tfile; otherwise we risk using half-initialized
+	 * object.
+	 */
+	rcu_assign_pointer(tfile->tun, tun);
+	rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
+	tun->numqueues++;
+	tun_set_real_num_queues(tun);
 out:
 	return err;
 }
@@ -1083,7 +1092,7 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 	tfile = rcu_dereference(tun->tfiles[txq]);
 
 	/* Drop packet if interface is not attached */
-	if (txq >= tun->numqueues)
+	if (!tfile)
 		goto drop;
 
 	if (!rcu_dereference(tun->steering_prog))
@@ -1274,6 +1283,7 @@ static int tun_xdp_xmit(struct net_device *dev, int n,
 
 	rcu_read_lock();
 
+resample:
 	numqueues = READ_ONCE(tun->numqueues);
 	if (!numqueues) {
 		rcu_read_unlock();
@@ -1282,6 +1292,8 @@ static int tun_xdp_xmit(struct net_device *dev, int n,
 
 	tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
 					    numqueues]);
+	if (unlikely(!tfile))
+		goto resample;
 
 	spin_lock(&tfile->tx_ring.producer_lock);
 	for (i = 0; i < n; i++) {
@@ -1716,9 +1728,6 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 	int skb_xdp = 1;
 	bool frags = tun_napi_frags_enabled(tfile);
 
-	if (!(tun->dev->flags & IFF_UP))
-		return -EIO;
-
 	if (!(tun->flags & IFF_NO_PI)) {
 		if (len < sizeof(pi))
 			return -EINVAL;
@@ -1820,6 +1829,8 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 			err = skb_copy_datagram_from_iter(skb, 0, from, len);
 
 		if (err) {
+			err = -EFAULT;
+drop:
 			this_cpu_inc(tun->pcpu_stats->rx_dropped);
 			kfree_skb(skb);
 			if (frags) {
@@ -1827,7 +1838,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 				mutex_unlock(&tfile->napi_mutex);
 			}
 
-			return -EFAULT;
+			return err;
 		}
 	}
 
@@ -1911,6 +1922,13 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 	    !tfile->detached)
 		rxhash = __skb_get_hash_symmetric(skb);
 
+	rcu_read_lock();
+	if (unlikely(!(tun->dev->flags & IFF_UP))) {
+		err = -EIO;
+		rcu_read_unlock();
+		goto drop;
+	}
+
 	if (frags) {
 		/* Exercise flow dissector code path. */
 		u32 headlen = eth_get_headlen(skb->data, skb_headlen(skb));
@@ -1918,6 +1936,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 		if (unlikely(headlen > skb_headlen(skb))) {
 			this_cpu_inc(tun->pcpu_stats->rx_dropped);
 			napi_free_frags(&tfile->napi);
+			rcu_read_unlock();
 			mutex_unlock(&tfile->napi_mutex);
 			WARN_ON(1);
 			return -ENOMEM;
@@ -1945,6 +1964,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 	} else {
 		netif_rx_ni(skb);
 	}
+	rcu_read_unlock();
 
 	stats = get_cpu_ptr(tun->pcpu_stats);
 	u64_stats_update_begin(&stats->syncp);
@@ -2120,9 +2140,9 @@ static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
 	}
 
 	add_wait_queue(&tfile->wq.wait, &wait);
-	current->state = TASK_INTERRUPTIBLE;
 
 	while (1) {
+		set_current_state(TASK_INTERRUPTIBLE);
 		ptr = ptr_ring_consume(&tfile->tx_ring);
 		if (ptr)
 			break;
@@ -2138,7 +2158,7 @@ static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
 		schedule();
 	}
 
-	current->state = TASK_RUNNING;
+	__set_current_state(TASK_RUNNING);
 	remove_wait_queue(&tfile->wq.wait, &wait);
 
 out: