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

Alexei Starovoitov says:

====================
pull-request: bpf 2020-02-19

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

We've added 10 non-merge commits during the last 10 day(s) which contain
a total of 10 files changed, 93 insertions(+), 31 deletions(-).

The main changes are:

1) batched bpf hashtab fixes from Brian and Yonghong.

2) various selftests and libbpf fixes.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/bpf.h

@@ -1045,9 +1045,9 @@ union bpf_attr {
  * 		supports redirection to the egress interface, and accepts no
  * 		flag at all.
  *
- * 		The same effect can be attained with the more generic
- * 		**bpf_redirect_map**\ (), which requires specific maps to be
- * 		used but offers better performance.
+ * 		The same effect can also be attained with the more generic
+ * 		**bpf_redirect_map**\ (), which uses a BPF map to store the
+ * 		redirect target instead of providing it directly to the helper.
  * 	Return
  * 		For XDP, the helper returns **XDP_REDIRECT** on success or
  * 		**XDP_ABORTED** on error. For other program types, the values
@@ -1611,13 +1611,11 @@ union bpf_attr {
  * 		the caller. Any higher bits in the *flags* argument must be
  * 		unset.
  *
- * 		When used to redirect packets to net devices, this helper
- * 		provides a high performance increase over **bpf_redirect**\ ().
- * 		This is due to various implementation details of the underlying
- * 		mechanisms, one of which is the fact that **bpf_redirect_map**\
- * 		() tries to send packet as a "bulk" to the device.
+ * 		See also bpf_redirect(), which only supports redirecting to an
+ * 		ifindex, but doesn't require a map to do so.
  * 	Return
- * 		**XDP_REDIRECT** on success, or **XDP_ABORTED** on error.
+ * 		**XDP_REDIRECT** on success, or the value of the two lower bits
+ * 		of the **flags* argument on error.
  *
  * int bpf_sk_redirect_map(struct sk_buff *skb, struct bpf_map *map, u32 key, u64 flags)
  * 	Description

kernel/bpf/btf.c

@@ -4142,7 +4142,7 @@ int btf_distill_func_proto(struct bpf_verifier_log *log,
  * EFAULT - verifier bug
  * 0 - 99% match. The last 1% is validated by the verifier.
  */
-int btf_check_func_type_match(struct bpf_verifier_log *log,
+static int btf_check_func_type_match(struct bpf_verifier_log *log,
 				     struct btf *btf1, const struct btf_type *t1,
 				     struct btf *btf2, const struct btf_type *t2)
 {

kernel/bpf/hashtab.c

@@ -56,6 +56,7 @@ struct htab_elem {
 			union {
 				struct bpf_htab *htab;
 				struct pcpu_freelist_node fnode;
+				struct htab_elem *batch_flink;
 			};
 		};
 	};
@@ -126,6 +127,17 @@ static void htab_free_elems(struct bpf_htab *htab)
 	bpf_map_area_free(htab->elems);
 }
 
+/* The LRU list has a lock (lru_lock). Each htab bucket has a lock
+ * (bucket_lock). If both locks need to be acquired together, the lock
+ * order is always lru_lock -> bucket_lock and this only happens in
+ * bpf_lru_list.c logic. For example, certain code path of
+ * bpf_lru_pop_free(), which is called by function prealloc_lru_pop(),
+ * will acquire lru_lock first followed by acquiring bucket_lock.
+ *
+ * In hashtab.c, to avoid deadlock, lock acquisition of
+ * bucket_lock followed by lru_lock is not allowed. In such cases,
+ * bucket_lock needs to be released first before acquiring lru_lock.
+ */
 static struct htab_elem *prealloc_lru_pop(struct bpf_htab *htab, void *key,
 					  u32 hash)
 {
@@ -1256,10 +1268,12 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map,
 	void __user *ukeys = u64_to_user_ptr(attr->batch.keys);
 	void *ubatch = u64_to_user_ptr(attr->batch.in_batch);
 	u32 batch, max_count, size, bucket_size;
+	struct htab_elem *node_to_free = NULL;
 	u64 elem_map_flags, map_flags;
 	struct hlist_nulls_head *head;
 	struct hlist_nulls_node *n;
-	unsigned long flags;
+	unsigned long flags = 0;
+	bool locked = false;
 	struct htab_elem *l;
 	struct bucket *b;
 	int ret = 0;
@@ -1319,15 +1333,25 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map,
 	dst_val = values;
 	b = &htab->buckets[batch];
 	head = &b->head;
+	/* do not grab the lock unless need it (bucket_cnt > 0). */
+	if (locked)
 		raw_spin_lock_irqsave(&b->lock, flags);
 
 	bucket_cnt = 0;
 	hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
 		bucket_cnt++;
 
+	if (bucket_cnt && !locked) {
+		locked = true;
+		goto again_nocopy;
+	}
+
 	if (bucket_cnt > (max_count - total)) {
 		if (total == 0)
 			ret = -ENOSPC;
+		/* Note that since bucket_cnt > 0 here, it is implicit
+		 * that the locked was grabbed, so release it.
+		 */
 		raw_spin_unlock_irqrestore(&b->lock, flags);
 		rcu_read_unlock();
 		this_cpu_dec(bpf_prog_active);
@@ -1337,6 +1361,9 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map,
 
 	if (bucket_cnt > bucket_size) {
 		bucket_size = bucket_cnt;
+		/* Note that since bucket_cnt > 0 here, it is implicit
+		 * that the locked was grabbed, so release it.
+		 */
 		raw_spin_unlock_irqrestore(&b->lock, flags);
 		rcu_read_unlock();
 		this_cpu_dec(bpf_prog_active);
@@ -1346,6 +1373,10 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map,
 		goto alloc;
 	}
 
+	/* Next block is only safe to run if you have grabbed the lock */
+	if (!locked)
+		goto next_batch;
+
 	hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
 		memcpy(dst_key, l->key, key_size);
 
@@ -1370,16 +1401,33 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map,
 		}
 		if (do_delete) {
 			hlist_nulls_del_rcu(&l->hash_node);
-			if (is_lru_map)
-				bpf_lru_push_free(&htab->lru, &l->lru_node);
-			else
+
+			/* bpf_lru_push_free() will acquire lru_lock, which
+			 * may cause deadlock. See comments in function
+			 * prealloc_lru_pop(). Let us do bpf_lru_push_free()
+			 * after releasing the bucket lock.
+			 */
+			if (is_lru_map) {
+				l->batch_flink = node_to_free;
+				node_to_free = l;
+			} else {
 				free_htab_elem(htab, l);
 			}
+		}
 		dst_key += key_size;
 		dst_val += value_size;
 	}
 
 	raw_spin_unlock_irqrestore(&b->lock, flags);
+	locked = false;
+
+	while (node_to_free) {
+		l = node_to_free;
+		node_to_free = node_to_free->batch_flink;
+		bpf_lru_push_free(&htab->lru, &l->lru_node);
+	}
+
+next_batch:
 	/* If we are not copying data, we can go to next bucket and avoid
 	 * unlocking the rcu.
 	 */

kernel/bpf/offload.c

@@ -321,7 +321,7 @@ int bpf_prog_offload_info_fill(struct bpf_prog_info *info,
 
 	ulen = info->jited_prog_len;
 	info->jited_prog_len = aux->offload->jited_len;
-	if (info->jited_prog_len & ulen) {
+	if (info->jited_prog_len && ulen) {
 		uinsns = u64_to_user_ptr(info->jited_prog_insns);
 		ulen = min_t(u32, info->jited_prog_len, ulen);
 		if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) {

net/xdp/xsk.c

@@ -217,6 +217,7 @@ static int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
 static void xsk_flush(struct xdp_sock *xs)
 {
 	xskq_prod_submit(xs->rx);
+	__xskq_cons_release(xs->umem->fq);
 	sock_def_readable(&xs->sk);
 }
 
@@ -304,6 +305,7 @@ void xsk_umem_consume_tx_done(struct xdp_umem *umem)
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(xs, &umem->xsk_list, list) {
+		__xskq_cons_release(xs->tx);
 		xs->sk.sk_write_space(&xs->sk);
 	}
 	rcu_read_unlock();

net/xdp/xsk_queue.h

@@ -271,7 +271,8 @@ static inline void xskq_cons_release(struct xsk_queue *q)
 {
 	/* To improve performance, only update local state here.
 	 * Reflect this to global state when we get new entries
-	 * from the ring in xskq_cons_get_entries().
+	 * from the ring in xskq_cons_get_entries() and whenever
+	 * Rx or Tx processing are completed in the NAPI loop.
 	 */
 	q->cached_cons++;
 }

tools/include/uapi/linux/bpf.h

@@ -1045,9 +1045,9 @@ union bpf_attr {
  * 		supports redirection to the egress interface, and accepts no
  * 		flag at all.
  *
- * 		The same effect can be attained with the more generic
- * 		**bpf_redirect_map**\ (), which requires specific maps to be
- * 		used but offers better performance.
+ * 		The same effect can also be attained with the more generic
+ * 		**bpf_redirect_map**\ (), which uses a BPF map to store the
+ * 		redirect target instead of providing it directly to the helper.
  * 	Return
  * 		For XDP, the helper returns **XDP_REDIRECT** on success or
  * 		**XDP_ABORTED** on error. For other program types, the values
@@ -1611,13 +1611,11 @@ union bpf_attr {
  * 		the caller. Any higher bits in the *flags* argument must be
  * 		unset.
  *
- * 		When used to redirect packets to net devices, this helper
- * 		provides a high performance increase over **bpf_redirect**\ ().
- * 		This is due to various implementation details of the underlying
- * 		mechanisms, one of which is the fact that **bpf_redirect_map**\
- * 		() tries to send packet as a "bulk" to the device.
+ * 		See also bpf_redirect(), which only supports redirecting to an
+ * 		ifindex, but doesn't require a map to do so.
  * 	Return
- * 		**XDP_REDIRECT** on success, or **XDP_ABORTED** on error.
+ * 		**XDP_REDIRECT** on success, or the value of the two lower bits
+ * 		of the **flags* argument on error.
  *
  * int bpf_sk_redirect_map(struct sk_buff *skb, struct bpf_map *map, u32 key, u64 flags)
  * 	Description

tools/lib/bpf/libbpf.c

@@ -24,6 +24,7 @@
 #include <endian.h>
 #include <fcntl.h>
 #include <errno.h>
+#include <ctype.h>
 #include <asm/unistd.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
@@ -1283,7 +1284,7 @@ static size_t bpf_map_mmap_sz(const struct bpf_map *map)
 static char *internal_map_name(struct bpf_object *obj,
 			       enum libbpf_map_type type)
 {
-	char map_name[BPF_OBJ_NAME_LEN];
+	char map_name[BPF_OBJ_NAME_LEN], *p;
 	const char *sfx = libbpf_type_to_btf_name[type];
 	int sfx_len = max((size_t)7, strlen(sfx));
 	int pfx_len = min((size_t)BPF_OBJ_NAME_LEN - sfx_len - 1,
@@ -1292,6 +1293,11 @@ static char *internal_map_name(struct bpf_object *obj,
 	snprintf(map_name, sizeof(map_name), "%.*s%.*s", pfx_len, obj->name,
 		 sfx_len, libbpf_type_to_btf_name[type]);
 
+	/* sanitise map name to characters allowed by kernel */
+	for (p = map_name; *p && p < map_name + sizeof(map_name); p++)
+		if (!isalnum(*p) && *p != '_' && *p != '.')
+			*p = '_';
+
 	return strdup(map_name);
 }
 

tools/testing/selftests/bpf/prog_tests/select_reuseport.c

@@ -506,8 +506,10 @@ static void test_syncookie(int type, sa_family_t family)
 		.pass_on_failure = 0,
 	};
 
-	if (type != SOCK_STREAM)
+	if (type != SOCK_STREAM) {
+		test__skip();
 		return;
+	}
 
 	/*
 	 * +1 for TCP-SYN and
@@ -822,8 +824,10 @@ void test_select_reuseport(void)
 		goto out;
 
 	saved_tcp_fo = read_int_sysctl(TCP_FO_SYSCTL);
+	if (saved_tcp_fo < 0)
+		goto out;
 	saved_tcp_syncookie = read_int_sysctl(TCP_SYNCOOKIE_SYSCTL);
-	if (saved_tcp_syncookie < 0 || saved_tcp_syncookie < 0)
+	if (saved_tcp_syncookie < 0)
 		goto out;
 
 	if (enable_fastopen())

tools/testing/selftests/bpf/prog_tests/sockmap_basic.c

@@ -3,6 +3,11 @@
 
 #include "test_progs.h"
 
+#define TCP_REPAIR		19	/* TCP sock is under repair right now */
+
+#define TCP_REPAIR_ON		1
+#define TCP_REPAIR_OFF_NO_WP	-1	/* Turn off without window probes */
+
 static int connected_socket_v4(void)
 {
 	struct sockaddr_in addr = {