Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Alexei Starovoitov says:

====================
pull-request: bpf 2018-07-07

The following pull-request contains BPF updates for your *net* tree.

Plenty of fixes for different components:

1) A set of critical fixes for sockmap and sockhash, from John Fastabend.

2) fixes for several race conditions in af_xdp, from Magnus Karlsson.

3) hash map refcnt fix, from Mauricio Vasquez.

4) samples/bpf fixes, from Taeung Song.

5) ifup+mtu check for xdp_redirect, from Toshiaki Makita.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/filter.h

@@ -765,8 +765,8 @@ static inline bool bpf_dump_raw_ok(void)
 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
 				       const struct bpf_insn *patch, u32 len);
 
-static inline int __xdp_generic_ok_fwd_dev(struct sk_buff *skb,
-					   struct net_device *fwd)
+static inline int xdp_ok_fwd_dev(const struct net_device *fwd,
+				 unsigned int pktlen)
 {
 	unsigned int len;
 
@@ -774,7 +774,7 @@ static inline int __xdp_generic_ok_fwd_dev(struct sk_buff *skb,
 		return -ENETDOWN;
 
 	len = fwd->mtu + fwd->hard_header_len + VLAN_HLEN;
-	if (skb->len > len)
+	if (pktlen > len)
 		return -EMSGSIZE;
 
 	return 0;

include/net/tcp.h

@@ -828,6 +828,10 @@ struct tcp_skb_cb {
 
 #define TCP_SKB_CB(__skb)	((struct tcp_skb_cb *)&((__skb)->cb[0]))
 
+static inline void bpf_compute_data_end_sk_skb(struct sk_buff *skb)
+{
+	TCP_SKB_CB(skb)->bpf.data_end = skb->data + skb_headlen(skb);
+}
 
 #if IS_ENABLED(CONFIG_IPV6)
 /* This is the variant of inet6_iif() that must be used by TCP,

include/net/xdp_sock.h

@@ -60,6 +60,10 @@ struct xdp_sock {
 	bool zc;
 	/* Protects multiple processes in the control path */
 	struct mutex mutex;
+	/* Mutual exclusion of NAPI TX thread and sendmsg error paths
+	 * in the SKB destructor callback.
+	 */
+	spinlock_t tx_completion_lock;
 	u64 rx_dropped;
 };
 

kernel/bpf/devmap.c

@@ -334,10 +334,15 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp,
 {
 	struct net_device *dev = dst->dev;
 	struct xdp_frame *xdpf;
+	int err;
 
 	if (!dev->netdev_ops->ndo_xdp_xmit)
 		return -EOPNOTSUPP;
 
+	err = xdp_ok_fwd_dev(dev, xdp->data_end - xdp->data);
+	if (unlikely(err))
+		return err;
+
 	xdpf = convert_to_xdp_frame(xdp);
 	if (unlikely(!xdpf))
 		return -EOVERFLOW;
@@ -350,7 +355,7 @@ int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,
 {
 	int err;
 
-	err = __xdp_generic_ok_fwd_dev(skb, dst->dev);
+	err = xdp_ok_fwd_dev(dst->dev, skb->len);
 	if (unlikely(err))
 		return err;
 	skb->dev = dst->dev;

kernel/bpf/hashtab.c

@@ -747,13 +747,15 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
 				 * old element will be freed immediately.
 				 * Otherwise return an error
 				 */
-				atomic_dec(&htab->count);
-				return ERR_PTR(-E2BIG);
+				l_new = ERR_PTR(-E2BIG);
+				goto dec_count;
 			}
 		l_new = kmalloc_node(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN,
 				     htab->map.numa_node);
-		if (!l_new)
-			return ERR_PTR(-ENOMEM);
+		if (!l_new) {
+			l_new = ERR_PTR(-ENOMEM);
+			goto dec_count;
+		}
 	}
 
 	memcpy(l_new->key, key, key_size);
@@ -766,7 +768,8 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
 						  GFP_ATOMIC | __GFP_NOWARN);
 			if (!pptr) {
 				kfree(l_new);
-				return ERR_PTR(-ENOMEM);
+				l_new = ERR_PTR(-ENOMEM);
+				goto dec_count;
 			}
 		}
 
@@ -780,6 +783,9 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
 
 	l_new->hash = hash;
 	return l_new;
+dec_count:
+	atomic_dec(&htab->count);
+	return l_new;
 }
 
 static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,

kernel/bpf/sockmap.c

@@ -312,10 +312,12 @@ static void bpf_tcp_close(struct sock *sk, long timeout)
 	struct smap_psock *psock;
 	struct sock *osk;
 
+	lock_sock(sk);
 	rcu_read_lock();
 	psock = smap_psock_sk(sk);
 	if (unlikely(!psock)) {
 		rcu_read_unlock();
+		release_sock(sk);
 		return sk->sk_prot->close(sk, timeout);
 	}
 
@@ -371,6 +373,7 @@ static void bpf_tcp_close(struct sock *sk, long timeout)
 		e = psock_map_pop(sk, psock);
 	}
 	rcu_read_unlock();
+	release_sock(sk);
 	close_fun(sk, timeout);
 }
 
@@ -568,7 +571,8 @@ static int free_sg(struct sock *sk, int start, struct sk_msg_buff *md)
 	while (sg[i].length) {
 		free += sg[i].length;
 		sk_mem_uncharge(sk, sg[i].length);
-		put_page(sg_page(&sg[i]));
+		if (!md->skb)
+			put_page(sg_page(&sg[i]));
 		sg[i].length = 0;
 		sg[i].page_link = 0;
 		sg[i].offset = 0;
@@ -577,6 +581,8 @@ static int free_sg(struct sock *sk, int start, struct sk_msg_buff *md)
 		if (i == MAX_SKB_FRAGS)
 			i = 0;
 	}
+	if (md->skb)
+		consume_skb(md->skb);
 
 	return free;
 }
@@ -1230,7 +1236,7 @@ static int smap_verdict_func(struct smap_psock *psock, struct sk_buff *skb)
 	 */
 	TCP_SKB_CB(skb)->bpf.sk_redir = NULL;
 	skb->sk = psock->sock;
-	bpf_compute_data_pointers(skb);
+	bpf_compute_data_end_sk_skb(skb);
 	preempt_disable();
 	rc = (*prog->bpf_func)(skb, prog->insnsi);
 	preempt_enable();
@@ -1485,7 +1491,7 @@ static int smap_parse_func_strparser(struct strparser *strp,
 	 * any socket yet.
 	 */
 	skb->sk = psock->sock;
-	bpf_compute_data_pointers(skb);
+	bpf_compute_data_end_sk_skb(skb);
 	rc = (*prog->bpf_func)(skb, prog->insnsi);
 	skb->sk = NULL;
 	rcu_read_unlock();
@@ -1896,7 +1902,7 @@ static int __sock_map_ctx_update_elem(struct bpf_map *map,
 		e = kzalloc(sizeof(*e), GFP_ATOMIC | __GFP_NOWARN);
 		if (!e) {
 			err = -ENOMEM;
-			goto out_progs;
+			goto out_free;
 		}
 	}
 
@@ -2069,7 +2075,13 @@ static int sock_map_update_elem(struct bpf_map *map,
 		return -EOPNOTSUPP;
 	}
 
+	lock_sock(skops.sk);
+	preempt_disable();
+	rcu_read_lock();
 	err = sock_map_ctx_update_elem(&skops, map, key, flags);
+	rcu_read_unlock();
+	preempt_enable();
+	release_sock(skops.sk);
 	fput(socket->file);
 	return err;
 }
@@ -2342,7 +2354,10 @@ static int sock_hash_ctx_update_elem(struct bpf_sock_ops_kern *skops,
 	if (err)
 		goto err;
 
-	/* bpf_map_update_elem() can be called in_irq() */
+	/* psock is valid here because otherwise above *ctx_update_elem would
+	 * have thrown an error. It is safe to skip error check.
+	 */
+	psock = smap_psock_sk(sock);
 	raw_spin_lock_bh(&b->lock);
 	l_old = lookup_elem_raw(head, hash, key, key_size);
 	if (l_old && map_flags == BPF_NOEXIST) {
@@ -2360,12 +2375,6 @@ static int sock_hash_ctx_update_elem(struct bpf_sock_ops_kern *skops,
 		goto bucket_err;
 	}
 
-	psock = smap_psock_sk(sock);
-	if (unlikely(!psock)) {
-		err = -EINVAL;
-		goto bucket_err;
-	}
-
 	rcu_assign_pointer(e->hash_link, l_new);
 	rcu_assign_pointer(e->htab,
 			   container_of(map, struct bpf_htab, map));
@@ -2388,12 +2397,10 @@ static int sock_hash_ctx_update_elem(struct bpf_sock_ops_kern *skops,
 	raw_spin_unlock_bh(&b->lock);
 	return 0;
 bucket_err:
+	smap_release_sock(psock, sock);
 	raw_spin_unlock_bh(&b->lock);
 err:
 	kfree(e);
-	psock = smap_psock_sk(sock);
-	if (psock)
-		smap_release_sock(psock, sock);
 	return err;
 }
 
@@ -2415,7 +2422,13 @@ static int sock_hash_update_elem(struct bpf_map *map,
 		return -EINVAL;
 	}
 
+	lock_sock(skops.sk);
+	preempt_disable();
+	rcu_read_lock();
 	err = sock_hash_ctx_update_elem(&skops, map, key, flags);
+	rcu_read_unlock();
+	preempt_enable();
+	release_sock(skops.sk);
 	fput(socket->file);
 	return err;
 }
@@ -2472,10 +2485,8 @@ struct sock  *__sock_hash_lookup_elem(struct bpf_map *map, void *key)
 	b = __select_bucket(htab, hash);
 	head = &b->head;
 
-	raw_spin_lock_bh(&b->lock);
 	l = lookup_elem_raw(head, hash, key, key_size);
 	sk = l ? l->sk : NULL;
-	raw_spin_unlock_bh(&b->lock);
 	return sk;
 }
 

kernel/bpf/syscall.c

@@ -735,7 +735,9 @@ static int map_update_elem(union bpf_attr *attr)
 	if (bpf_map_is_dev_bound(map)) {
 		err = bpf_map_offload_update_elem(map, key, value, attr->flags);
 		goto out;
-	} else if (map->map_type == BPF_MAP_TYPE_CPUMAP) {
+	} else if (map->map_type == BPF_MAP_TYPE_CPUMAP ||
+		   map->map_type == BPF_MAP_TYPE_SOCKHASH ||
+		   map->map_type == BPF_MAP_TYPE_SOCKMAP) {
 		err = map->ops->map_update_elem(map, key, value, attr->flags);
 		goto out;
 	}

net/core/filter.c

@@ -1762,6 +1762,37 @@ static const struct bpf_func_proto bpf_skb_pull_data_proto = {
 	.arg2_type	= ARG_ANYTHING,
 };
 
+static inline int sk_skb_try_make_writable(struct sk_buff *skb,
+					   unsigned int write_len)
+{
+	int err = __bpf_try_make_writable(skb, write_len);
+
+	bpf_compute_data_end_sk_skb(skb);
+	return err;
+}
+
+BPF_CALL_2(sk_skb_pull_data, struct sk_buff *, skb, u32, len)
+{
+	/* Idea is the following: should the needed direct read/write
+	 * test fail during runtime, we can pull in more data and redo
+	 * again, since implicitly, we invalidate previous checks here.
+	 *
+	 * Or, since we know how much we need to make read/writeable,
+	 * this can be done once at the program beginning for direct
+	 * access case. By this we overcome limitations of only current
+	 * headroom being accessible.
+	 */
+	return sk_skb_try_make_writable(skb, len ? : skb_headlen(skb));
+}
+
+static const struct bpf_func_proto sk_skb_pull_data_proto = {
+	.func		= sk_skb_pull_data,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_ANYTHING,
+};
+
 BPF_CALL_5(bpf_l3_csum_replace, struct sk_buff *, skb, u32, offset,
 	   u64, from, u64, to, u64, flags)
 {
@@ -2779,7 +2810,8 @@ static int bpf_skb_net_shrink(struct sk_buff *skb, u32 len_diff)
 
 static u32 __bpf_skb_max_len(const struct sk_buff *skb)
 {
-	return skb->dev->mtu + skb->dev->hard_header_len;
+	return skb->dev ? skb->dev->mtu + skb->dev->hard_header_len :
+			  SKB_MAX_ALLOC;
 }
 
 static int bpf_skb_adjust_net(struct sk_buff *skb, s32 len_diff)
@@ -2863,8 +2895,8 @@ static int bpf_skb_trim_rcsum(struct sk_buff *skb, unsigned int new_len)
 	return __skb_trim_rcsum(skb, new_len);
 }
 
-BPF_CALL_3(bpf_skb_change_tail, struct sk_buff *, skb, u32, new_len,
-	   u64, flags)
+static inline int __bpf_skb_change_tail(struct sk_buff *skb, u32 new_len,
+					u64 flags)
 {
 	u32 max_len = __bpf_skb_max_len(skb);
 	u32 min_len = __bpf_skb_min_len(skb);
@@ -2900,6 +2932,13 @@ BPF_CALL_3(bpf_skb_change_tail, struct sk_buff *, skb, u32, new_len,
 		if (!ret && skb_is_gso(skb))
 			skb_gso_reset(skb);
 	}
+	return ret;
+}
+
+BPF_CALL_3(bpf_skb_change_tail, struct sk_buff *, skb, u32, new_len,
+	   u64, flags)
+{
+	int ret = __bpf_skb_change_tail(skb, new_len, flags);
 
 	bpf_compute_data_pointers(skb);
 	return ret;
@@ -2914,8 +2953,26 @@ static const struct bpf_func_proto bpf_skb_change_tail_proto = {
 	.arg3_type	= ARG_ANYTHING,
 };
 
-BPF_CALL_3(bpf_skb_change_head, struct sk_buff *, skb, u32, head_room,
+BPF_CALL_3(sk_skb_change_tail, struct sk_buff *, skb, u32, new_len,
 	   u64, flags)
+{
+	int ret = __bpf_skb_change_tail(skb, new_len, flags);
+
+	bpf_compute_data_end_sk_skb(skb);
+	return ret;
+}
+
+static const struct bpf_func_proto sk_skb_change_tail_proto = {
+	.func		= sk_skb_change_tail,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+static inline int __bpf_skb_change_head(struct sk_buff *skb, u32 head_room,
+					u64 flags)
 {
 	u32 max_len = __bpf_skb_max_len(skb);
 	u32 new_len = skb->len + head_room;
@@ -2941,8 +2998,16 @@ BPF_CALL_3(bpf_skb_change_head, struct sk_buff *, skb, u32, head_room,
 		skb_reset_mac_header(skb);
 	}
 
+	return ret;
+}
+
+BPF_CALL_3(bpf_skb_change_head, struct sk_buff *, skb, u32, head_room,
+	   u64, flags)
+{
+	int ret = __bpf_skb_change_head(skb, head_room, flags);
+
 	bpf_compute_data_pointers(skb);
-	return 0;
+	return ret;
 }
 
 static const struct bpf_func_proto bpf_skb_change_head_proto = {
@@ -2954,6 +3019,23 @@ static const struct bpf_func_proto bpf_skb_change_head_proto = {
 	.arg3_type	= ARG_ANYTHING,
 };
 
+BPF_CALL_3(sk_skb_change_head, struct sk_buff *, skb, u32, head_room,
+	   u64, flags)
+{
+	int ret = __bpf_skb_change_head(skb, head_room, flags);
+
+	bpf_compute_data_end_sk_skb(skb);
+	return ret;
+}
+
+static const struct bpf_func_proto sk_skb_change_head_proto = {
+	.func		= sk_skb_change_head,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_ANYTHING,
+};
 static unsigned long xdp_get_metalen(const struct xdp_buff *xdp)
 {
 	return xdp_data_meta_unsupported(xdp) ? 0 :
@@ -3046,12 +3128,16 @@ static int __bpf_tx_xdp(struct net_device *dev,
 			u32 index)
 {
 	struct xdp_frame *xdpf;
-	int sent;
+	int err, sent;
 
 	if (!dev->netdev_ops->ndo_xdp_xmit) {
 		return -EOPNOTSUPP;
 	}
 
+	err = xdp_ok_fwd_dev(dev, xdp->data_end - xdp->data);
+	if (unlikely(err))
+		return err;
+
 	xdpf = convert_to_xdp_frame(xdp);
 	if (unlikely(!xdpf))
 		return -EOVERFLOW;
@@ -3285,7 +3371,8 @@ int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb,
 		goto err;
 	}
 
-	if (unlikely((err = __xdp_generic_ok_fwd_dev(skb, fwd))))
+	err = xdp_ok_fwd_dev(fwd, skb->len);
+	if (unlikely(err))
 		goto err;
 
 	skb->dev = fwd;
@@ -4617,9 +4704,12 @@ bool bpf_helper_changes_pkt_data(void *func)
 	    func == bpf_skb_store_bytes ||
 	    func == bpf_skb_change_proto ||
 	    func == bpf_skb_change_head ||
+	    func == sk_skb_change_head ||
 	    func == bpf_skb_change_tail ||
+	    func == sk_skb_change_tail ||
 	    func == bpf_skb_adjust_room ||
 	    func == bpf_skb_pull_data ||
+	    func == sk_skb_pull_data ||
 	    func == bpf_clone_redirect ||
 	    func == bpf_l3_csum_replace ||
 	    func == bpf_l4_csum_replace ||
@@ -4871,11 +4961,11 @@ sk_skb_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 	case BPF_FUNC_skb_load_bytes:
 		return &bpf_skb_load_bytes_proto;
 	case BPF_FUNC_skb_pull_data:
-		return &bpf_skb_pull_data_proto;
+		return &sk_skb_pull_data_proto;
 	case BPF_FUNC_skb_change_tail:
-		return &bpf_skb_change_tail_proto;
+		return &sk_skb_change_tail_proto;
 	case BPF_FUNC_skb_change_head:
-		return &bpf_skb_change_head_proto;
+		return &sk_skb_change_head_proto;
 	case BPF_FUNC_get_socket_cookie:
 		return &bpf_get_socket_cookie_proto;
 	case BPF_FUNC_get_socket_uid:

net/xdp/xsk.c

@@ -199,8 +199,11 @@ static void xsk_destruct_skb(struct sk_buff *skb)
 {
 	u64 addr = (u64)(long)skb_shinfo(skb)->destructor_arg;
 	struct xdp_sock *xs = xdp_sk(skb->sk);
+	unsigned long flags;
 
+	spin_lock_irqsave(&xs->tx_completion_lock, flags);
 	WARN_ON_ONCE(xskq_produce_addr(xs->umem->cq, addr));
+	spin_unlock_irqrestore(&xs->tx_completion_lock, flags);
 
 	sock_wfree(skb);
 }
@@ -268,15 +271,15 @@ static int xsk_generic_xmit(struct sock *sk, struct msghdr *m,
 		skb->destructor = xsk_destruct_skb;
 
 		err = dev_direct_xmit(skb, xs->queue_id);
+		xskq_discard_desc(xs->tx);
 		/* Ignore NET_XMIT_CN as packet might have been sent */
 		if (err == NET_XMIT_DROP || err == NETDEV_TX_BUSY) {
-			err = -EAGAIN;
-			/* SKB consumed by dev_direct_xmit() */
+			/* SKB completed but not sent */
+			err = -EBUSY;
 			goto out;
 		}
 
 		sent_frame = true;
-		xskq_discard_desc(xs->tx);
 	}
 
 out:
@@ -755,6 +758,7 @@ static int xsk_create(struct net *net, struct socket *sock, int protocol,
 
 	xs = xdp_sk(sk);
 	mutex_init(&xs->mutex);
+	spin_lock_init(&xs->tx_completion_lock);
 
 	local_bh_disable();
 	sock_prot_inuse_add(net, &xsk_proto, 1);

net/xdp/xsk_queue.h

@@ -62,14 +62,9 @@ static inline u32 xskq_nb_avail(struct xsk_queue *q, u32 dcnt)
 	return (entries > dcnt) ? dcnt : entries;
 }
 
-static inline u32 xskq_nb_free_lazy(struct xsk_queue *q, u32 producer)
-{
-	return q->nentries - (producer - q->cons_tail);
-}
-
 static inline u32 xskq_nb_free(struct xsk_queue *q, u32 producer, u32 dcnt)
 {
-	u32 free_entries = xskq_nb_free_lazy(q, producer);
+	u32 free_entries = q->nentries - (producer - q->cons_tail);
 
 	if (free_entries >= dcnt)
 		return free_entries;
@@ -129,7 +124,7 @@ static inline int xskq_produce_addr(struct xsk_queue *q, u64 addr)
 {
 	struct xdp_umem_ring *ring = (struct xdp_umem_ring *)q->ring;
 
-	if (xskq_nb_free(q, q->prod_tail, LAZY_UPDATE_THRESHOLD) == 0)
+	if (xskq_nb_free(q, q->prod_tail, 1) == 0)
 		return -ENOSPC;
 
 	ring->desc[q->prod_tail++ & q->ring_mask] = addr;

samples/bpf/.gitignore

@@ -0,0 +1,49 @@
+cpustat
+fds_example
+lathist
+load_sock_ops
+lwt_len_hist
+map_perf_test
+offwaketime
+per_socket_stats_example
+sampleip
+sock_example
+sockex1
+sockex2
+sockex3
+spintest
+syscall_nrs.h
+syscall_tp
+task_fd_query
+tc_l2_redirect
+test_cgrp2_array_pin
+test_cgrp2_attach
+test_cgrp2_attach2
+test_cgrp2_sock
+test_cgrp2_sock2
+test_current_task_under_cgroup
+test_lru_dist
+test_map_in_map
+test_overhead
+test_probe_write_user
+trace_event
+trace_output
+tracex1
+tracex2
+tracex3
+tracex4
+tracex5
+tracex6
+tracex7
+xdp1
+xdp2
+xdp_adjust_tail
+xdp_fwd
+xdp_monitor
+xdp_redirect
+xdp_redirect_cpu
+xdp_redirect_map
+xdp_router_ipv4
+xdp_rxq_info
+xdp_tx_iptunnel
+xdpsock

samples/bpf/parse_varlen.c

@@ -6,6 +6,7 @@
  */
 #define KBUILD_MODNAME "foo"
 #include <linux/if_ether.h>
+#include <linux/if_vlan.h>
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <linux/in.h>
@@ -108,11 +109,6 @@ static int parse_ipv6(void *data, uint64_t nh_off, void *data_end)
 	return 0;
 }
 
-struct vlan_hdr {
-	uint16_t h_vlan_TCI;
-	uint16_t h_vlan_encapsulated_proto;
-};
-
 SEC("varlen")
 int handle_ingress(struct __sk_buff *skb)
 {

samples/bpf/test_overhead_user.c

@@ -6,6 +6,7 @@
  */
 #define _GNU_SOURCE
 #include <sched.h>
+#include <errno.h>
 #include <stdio.h>
 #include <sys/types.h>
 #include <asm/unistd.h>
@@ -44,8 +45,13 @@ static void test_task_rename(int cpu)
 		exit(1);
 	}
 	start_time = time_get_ns();
-	for (i = 0; i < MAX_CNT; i++)
-		write(fd, buf, sizeof(buf));
+	for (i = 0; i < MAX_CNT; i++) {
+		if (write(fd, buf, sizeof(buf)) < 0) {
+			printf("task rename failed: %s\n", strerror(errno));
+			close(fd);
+			return;
+		}
+	}
 	printf("task_rename:%d: %lld events per sec\n",
 	       cpu, MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
 	close(fd);
@@ -63,8 +69,13 @@ static void test_urandom_read(int cpu)
 		exit(1);
 	}
 	start_time = time_get_ns();
-	for (i = 0; i < MAX_CNT; i++)
-		read(fd, buf, sizeof(buf));
+	for (i = 0; i < MAX_CNT; i++) {
+		if (read(fd, buf, sizeof(buf)) < 0) {
+			printf("failed to read from /dev/urandom: %s\n", strerror(errno));
+			close(fd);
+			return;
+		}
+	}
 	printf("urandom_read:%d: %lld events per sec\n",
 	       cpu, MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
 	close(fd);

samples/bpf/trace_event_user.c

@@ -122,6 +122,16 @@ static void print_stacks(void)
 	}
 }
 
+static inline int generate_load(void)
+{
+	if (system("dd if=/dev/zero of=/dev/null count=5000k status=none") < 0) {
+		printf("failed to generate some load with dd: %s\n", strerror(errno));
+		return -1;
+	}
+
+	return 0;
+}
+
 static void test_perf_event_all_cpu(struct perf_event_attr *attr)
 {
 	int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
@@ -142,7 +152,11 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
 		assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
 		assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE) == 0);
 	}
-	system("dd if=/dev/zero of=/dev/null count=5000k status=none");
+
+	if (generate_load() < 0) {
+		error = 1;
+		goto all_cpu_err;
+	}
 	print_stacks();
 all_cpu_err:
 	for (i--; i >= 0; i--) {
@@ -156,7 +170,7 @@ all_cpu_err:
 
 static void test_perf_event_task(struct perf_event_attr *attr)
 {
-	int pmu_fd;
+	int pmu_fd, error = 0;
 
 	/* per task perf event, enable inherit so the "dd ..." command can be traced properly.
 	 * Enabling inherit will cause bpf_perf_prog_read_time helper failure.
@@ -171,10 +185,17 @@ static void test_perf_event_task(struct perf_event_attr *attr)
 	}
 	assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
 	assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE) == 0);
-	system("dd if=/dev/zero of=/dev/null count=5000k status=none");
+
+	if (generate_load() < 0) {
+		error = 1;
+		goto err;
+	}
 	print_stacks();
+err:
 	ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);
 	close(pmu_fd);
+	if (error)
+		int_exit(0);
 }
 
 static void test_bpf_perf_event(void)

samples/bpf/xdpsock_user.c

@@ -729,7 +729,7 @@ static void kick_tx(int fd)
 	int ret;
 
 	ret = sendto(fd, NULL, 0, MSG_DONTWAIT, NULL, 0);
-	if (ret >= 0 || errno == ENOBUFS || errno == EAGAIN)
+	if (ret >= 0 || errno == ENOBUFS || errno == EAGAIN || errno == EBUSY)
 		return;
 	lassert(0);
 }