Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
pull-request: bpf-next 2020-12-14

1) Expose bpf_sk_storage_*() helpers to iterator programs, from Florent Revest.

2) Add AF_XDP selftests based on veth devs to BPF selftests, from Weqaar Janjua.

3) Support for finding BTF based kernel attach targets through libbpf's
   bpf_program__set_attach_target() API, from Andrii Nakryiko.

4) Permit pointers on stack for helper calls in the verifier, from Yonghong Song.

5) Fix overflows in hash map elem size after rlimit removal, from Eric Dumazet.

6) Get rid of direct invocation of llc in BPF selftests, from Andrew Delgadillo.

7) Fix xsk_recvmsg() to reorder socket state check before access, from Björn Töpel.

8) Add new libbpf API helper to retrieve ring buffer epoll fd, from Brendan Jackman.

9) Batch of minor BPF selftest improvements all over the place, from Florian Lehner,
   KP Singh, Jiri Olsa and various others.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (31 commits)
  selftests/bpf: Add a test for ptr_to_map_value on stack for helper access
  bpf: Permits pointers on stack for helper calls
  libbpf: Expose libbpf ring_buffer epoll_fd
  selftests/bpf: Add set_attach_target() API selftest for module target
  libbpf: Support modules in bpf_program__set_attach_target() API
  selftests/bpf: Silence ima_setup.sh when not running in verbose mode.
  selftests/bpf: Drop the need for LLVM's llc
  selftests/bpf: fix bpf_testmod.ko recompilation logic
  samples/bpf: Fix possible hang in xdpsock with multiple threads
  selftests/bpf: Make selftest compilation work on clang 11
  selftests/bpf: Xsk selftests - adding xdpxceiver to .gitignore
  selftests/bpf: Drop tcp-{client,server}.py from Makefile
  selftests/bpf: Xsk selftests - Bi-directional Sockets - SKB, DRV
  selftests/bpf: Xsk selftests - Socket Teardown - SKB, DRV
  selftests/bpf: Xsk selftests - DRV POLL, NOPOLL
  selftests/bpf: Xsk selftests - SKB POLL, NOPOLL
  selftests/bpf: Xsk selftests framework
  bpf: Only provide bpf_sock_from_file with CONFIG_NET
  bpf: Return -ENOTSUPP when attaching to non-kernel BTF
  xsk: Validate socket state in xsk_recvmsg, prior touching socket members
  ...
====================

Link: https://lore.kernel.org/r/20201214214316.20642-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

40 files changed, 2063 insertions, 114 deletions

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 73c346e503d7..19499b7bb82c 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -416,12 +416,11 @@ static inline void ep_set_busy_poll_napi_id(struct epitem *epi)
 	unsigned int napi_id;
 	struct socket *sock;
 	struct sock *sk;
-	int err;
 
 	if (!net_busy_loop_on())
 		return;
 
-	sock = sock_from_file(epi->ffd.file, &err);
+	sock = sock_from_file(epi->ffd.file);
 	if (!sock)
 		return;
 
diff --git a/fs/io_uring.c b/fs/io_uring.c
index a2a7c65a77aa..a97488c7b2cf 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4356,9 +4356,9 @@ static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
 	unsigned flags;
 	int ret;
 
-	sock = sock_from_file(req->file, &ret);
+	sock = sock_from_file(req->file);
 	if (unlikely(!sock))
-		return ret;
+		return -ENOTSOCK;
 
 	if (req->async_data) {
 		kmsg = req->async_data;
@@ -4405,9 +4405,9 @@ static int io_send(struct io_kiocb *req, bool force_nonblock,
 	unsigned flags;
 	int ret;
 
-	sock = sock_from_file(req->file, &ret);
+	sock = sock_from_file(req->file);
 	if (unlikely(!sock))
-		return ret;
+		return -ENOTSOCK;
 
 	ret = import_single_range(WRITE, sr->buf, sr->len, &iov, &msg.msg_iter);
 	if (unlikely(ret))
@@ -4585,9 +4585,9 @@ static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
 	unsigned flags;
 	int ret, cflags = 0;
 
-	sock = sock_from_file(req->file, &ret);
+	sock = sock_from_file(req->file);
 	if (unlikely(!sock))
-		return ret;
+		return -ENOTSOCK;
 
 	if (req->async_data) {
 		kmsg = req->async_data;
@@ -4648,9 +4648,9 @@ static int io_recv(struct io_kiocb *req, bool force_nonblock,
 	unsigned flags;
 	int ret, cflags = 0;
 
-	sock = sock_from_file(req->file, &ret);
+	sock = sock_from_file(req->file);
 	if (unlikely(!sock))
-		return ret;
+		return -ENOTSOCK;
 
 	if (req->flags & REQ_F_BUFFER_SELECT) {
 		kbuf = io_recv_buffer_select(req, !force_nonblock);
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index d05e75ed8c1b..07cb5d15e743 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1859,6 +1859,7 @@ extern const struct bpf_func_proto bpf_snprintf_btf_proto;
 extern const struct bpf_func_proto bpf_per_cpu_ptr_proto;
 extern const struct bpf_func_proto bpf_this_cpu_ptr_proto;
 extern const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto;
+extern const struct bpf_func_proto bpf_sock_from_file_proto;
 
 const struct bpf_func_proto *bpf_tracing_func_proto(
 	enum bpf_func_id func_id, const struct bpf_prog *prog);
diff --git a/include/linux/net.h b/include/linux/net.h
index 0dcd51feef02..9e2324efc26a 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -240,7 +240,7 @@ int sock_sendmsg(struct socket *sock, struct msghdr *msg);
 int sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags);
 struct file *sock_alloc_file(struct socket *sock, int flags, const char *dname);
 struct socket *sockfd_lookup(int fd, int *err);
-struct socket *sock_from_file(struct file *file, int *err);
+struct socket *sock_from_file(struct file *file);
 #define		     sockfd_put(sock) fput(sock->file)
 int net_ratelimit(void);
 
diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h
index cd24e8a59529..76a97176ab81 100644
--- a/include/trace/events/xdp.h
+++ b/include/trace/events/xdp.h
@@ -145,17 +145,17 @@ DEFINE_EVENT(xdp_redirect_template, xdp_redirect_err,
 	TP_ARGS(dev, xdp, tgt, err, map, index)
 );
 
-#define _trace_xdp_redirect(dev, xdp, to)		\
-	 trace_xdp_redirect(dev, xdp, NULL, 0, NULL, to);
+#define _trace_xdp_redirect(dev, xdp, to)				\
+	 trace_xdp_redirect(dev, xdp, NULL, 0, NULL, to)
 
-#define _trace_xdp_redirect_err(dev, xdp, to, err)	\
-	 trace_xdp_redirect_err(dev, xdp, NULL, err, NULL, to);
+#define _trace_xdp_redirect_err(dev, xdp, to, err)			\
+	 trace_xdp_redirect_err(dev, xdp, NULL, err, NULL, to)
 
 #define _trace_xdp_redirect_map(dev, xdp, to, map, index)		\
-	 trace_xdp_redirect(dev, xdp, to, 0, map, index);
+	 trace_xdp_redirect(dev, xdp, to, 0, map, index)
 
 #define _trace_xdp_redirect_map_err(dev, xdp, to, map, index, err)	\
-	 trace_xdp_redirect_err(dev, xdp, to, err, map, index);
+	 trace_xdp_redirect_err(dev, xdp, to, err, map, index)
 
 /* not used anymore, but kept around so as not to break old programs */
 DEFINE_EVENT(xdp_redirect_template, xdp_redirect_map,
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 7e9931b6c735..77d7c1bb2923 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3822,6 +3822,14 @@ union bpf_attr {
  *		The **hash_algo** is returned on success,
  *		**-EOPNOTSUP** if IMA is disabled or **-EINVAL** if
  *		invalid arguments are passed.
+ *
+ * struct socket *bpf_sock_from_file(struct file *file)
+ *	Description
+ *		If the given file represents a socket, returns the associated
+ *		socket.
+ *	Return
+ *		A pointer to a struct socket on success or NULL if the file is
+ *		not a socket.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -3986,6 +3994,7 @@ union bpf_attr {
 	FN(bprm_opts_set),		\
 	FN(ktime_get_coarse_ns),	\
 	FN(ima_inode_hash),		\
+	FN(sock_from_file),		\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index fe7a0733a63a..7e848200cd26 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -224,7 +224,7 @@ static void *fd_htab_map_get_ptr(const struct bpf_map *map, struct htab_elem *l)
 
 static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i)
 {
-	return (struct htab_elem *) (htab->elems + i * htab->elem_size);
+	return (struct htab_elem *) (htab->elems + i * (u64)htab->elem_size);
 }
 
 static void htab_free_elems(struct bpf_htab *htab)
@@ -280,7 +280,7 @@ static int prealloc_init(struct bpf_htab *htab)
 	if (!htab_is_percpu(htab) && !htab_is_lru(htab))
 		num_entries += num_possible_cpus();
 
-	htab->elems = bpf_map_area_alloc(htab->elem_size * num_entries,
+	htab->elems = bpf_map_area_alloc((u64)htab->elem_size * num_entries,
 					 htab->map.numa_node);
 	if (!htab->elems)
 		return -ENOMEM;
@@ -1412,7 +1412,7 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map,
 	void *keys = NULL, *values = NULL, *value, *dst_key, *dst_val;
 	void __user *uvalues = u64_to_user_ptr(attr->batch.values);
 	void __user *ukeys = u64_to_user_ptr(attr->batch.keys);
-	void *ubatch = u64_to_user_ptr(attr->batch.in_batch);
+	void __user *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;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 0cd3cc2af9c1..287be337d5f6 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2121,8 +2121,11 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
 			if (IS_ERR(attach_btf))
 				return -EINVAL;
 			if (!btf_is_kernel(attach_btf)) {
+				/* attaching through specifying bpf_prog's BTF
+				 * objects directly might be supported eventually
+				 */
 				btf_put(attach_btf);
-				return -EINVAL;
+				return -ENOTSUPP;
 			}
 		}
 	} else if (attr->attach_btf_id) {
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index d43b30c92c7d..17270b8404f1 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3767,7 +3767,8 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno,
 			goto mark;
 
 		if (state->stack[spi].slot_type[0] == STACK_SPILL &&
-		    state->stack[spi].spilled_ptr.type == SCALAR_VALUE) {
+		    (state->stack[spi].spilled_ptr.type == SCALAR_VALUE ||
+		     env->allow_ptr_leaks)) {
 			__mark_reg_unknown(env, &state->stack[spi].spilled_ptr);
 			for (j = 0; j < BPF_REG_SIZE; j++)
 				state->stack[spi].slot_type[j] = STACK_MISC;
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index fb2fbcbf6de6..4be771df5549 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1758,6 +1758,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_sk_storage_get_tracing_proto;
 	case BPF_FUNC_sk_storage_delete:
 		return &bpf_sk_storage_delete_tracing_proto;
+	case BPF_FUNC_sock_from_file:
+		return &bpf_sock_from_file_proto;
 #endif
 	case BPF_FUNC_seq_printf:
 		return prog->expected_attach_type == BPF_TRACE_ITER ?
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index a32037daa933..4edd033e899c 100644
--- a/net/core/bpf_sk_storage.c
+++ b/net/core/bpf_sk_storage.c
@@ -394,6 +394,7 @@ static bool bpf_sk_storage_tracing_allowed(const struct bpf_prog *prog)
 	 * use the bpf_sk_storage_(get|delete) helper.
 	 */
 	switch (prog->expected_attach_type) {
+	case BPF_TRACE_ITER:
 	case BPF_TRACE_RAW_TP:
 		/* bpf_sk_storage has no trace point */
 		return true;
diff --git a/net/core/filter.c b/net/core/filter.c
index 77001a35768f..255aeee72402 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -10413,6 +10413,24 @@ const struct bpf_func_proto bpf_skc_to_udp6_sock_proto = {
 	.ret_btf_id		= &btf_sock_ids[BTF_SOCK_TYPE_UDP6],
 };
 
+BPF_CALL_1(bpf_sock_from_file, struct file *, file)
+{
+	return (unsigned long)sock_from_file(file);
+}
+
+BTF_ID_LIST(bpf_sock_from_file_btf_ids)
+BTF_ID(struct, socket)
+BTF_ID(struct, file)
+
+const struct bpf_func_proto bpf_sock_from_file_proto = {
+	.func		= bpf_sock_from_file,
+	.gpl_only	= false,
+	.ret_type	= RET_PTR_TO_BTF_ID_OR_NULL,
+	.ret_btf_id	= &bpf_sock_from_file_btf_ids[0],
+	.arg1_type	= ARG_PTR_TO_BTF_ID,
+	.arg1_btf_id	= &bpf_sock_from_file_btf_ids[1],
+};
+
 static const struct bpf_func_proto *
 bpf_sk_base_func_proto(enum bpf_func_id func_id)
 {
diff --git a/net/core/netclassid_cgroup.c b/net/core/netclassid_cgroup.c
index 41b24cd31562..b49c57d35a88 100644
--- a/net/core/netclassid_cgroup.c
+++ b/net/core/netclassid_cgroup.c
@@ -68,9 +68,8 @@ struct update_classid_context {
 
 static int update_classid_sock(const void *v, struct file *file, unsigned n)
 {
-	int err;
 	struct update_classid_context *ctx = (void *)v;
-	struct socket *sock = sock_from_file(file, &err);
+	struct socket *sock = sock_from_file(file);
 
 	if (sock) {
 		spin_lock(&cgroup_sk_update_lock);
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index 9bd4cab7d510..99a431c56f23 100644
--- a/net/core/netprio_cgroup.c
+++ b/net/core/netprio_cgroup.c
@@ -220,8 +220,7 @@ static ssize_t write_priomap(struct kernfs_open_file *of,
 
 static int update_netprio(const void *v, struct file *file, unsigned n)
 {
-	int err;
-	struct socket *sock = sock_from_file(file, &err);
+	struct socket *sock = sock_from_file(file);
 	if (sock) {
 		spin_lock(&cgroup_sk_update_lock);
 		sock_cgroup_set_prioidx(&sock->sk->sk_cgrp_data,
diff --git a/net/core/sock.c b/net/core/sock.c
index 4fd7e785f177..bbcd4b97eddd 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2827,14 +2827,8 @@ EXPORT_SYMBOL(sock_no_mmap);
 void __receive_sock(struct file *file)
 {
 	struct socket *sock;
-	int error;
 
-	/*
-	 * The resulting value of "error" is ignored here since we only
-	 * need to take action when the file is a socket and testing
-	 * "sock" for NULL is sufficient.
-	 */
-	sock = sock_from_file(file, &error);
+	sock = sock_from_file(file);
 	if (sock) {
 		sock_update_netprioidx(&sock->sk->sk_cgrp_data);
 		sock_update_classid(&sock->sk->sk_cgrp_data);
diff --git a/net/socket.c b/net/socket.c
index bfef11ba35b8..9a240b45bdf3 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -445,17 +445,15 @@ static int sock_map_fd(struct socket *sock, int flags)
 /**
  *	sock_from_file - Return the &socket bounded to @file.
  *	@file: file
- *	@err: pointer to an error code return
  *
- *	On failure returns %NULL and assigns -ENOTSOCK to @err.
+ *	On failure returns %NULL.
  */
 
-struct socket *sock_from_file(struct file *file, int *err)
+struct socket *sock_from_file(struct file *file)
 {
 	if (file->f_op == &socket_file_ops)
 		return file->private_data;	/* set in sock_map_fd */
 
-	*err = -ENOTSOCK;
 	return NULL;
 }
 EXPORT_SYMBOL(sock_from_file);
@@ -484,9 +482,11 @@ struct socket *sockfd_lookup(int fd, int *err)
 		return NULL;
 	}
 
-	sock = sock_from_file(file, err);
-	if (!sock)
+	sock = sock_from_file(file);
+	if (!sock) {
+		*err = -ENOTSOCK;
 		fput(file);
+	}
 	return sock;
 }
 EXPORT_SYMBOL(sockfd_lookup);
@@ -498,11 +498,12 @@ static struct socket *sockfd_lookup_light(int fd, int *err, int *fput_needed)
 
 	*err = -EBADF;
 	if (f.file) {
-		sock = sock_from_file(f.file, err);
+		sock = sock_from_file(f.file);
 		if (likely(sock)) {
 			*fput_needed = f.flags & FDPUT_FPUT;
 			return sock;
 		}
+		*err = -ENOTSOCK;
 		fdput(f);
 	}
 	return NULL;
@@ -1693,9 +1694,11 @@ int __sys_accept4_file(struct file *file, unsigned file_flags,
 	if (SOCK_NONBLOCK != O_NONBLOCK && (flags & SOCK_NONBLOCK))
 		flags = (flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
 
-	sock = sock_from_file(file, &err);
-	if (!sock)
+	sock = sock_from_file(file);
+	if (!sock) {
+		err = -ENOTSOCK;
 		goto out;
+	}
 
 	err = -ENFILE;
 	newsock = sock_alloc();
@@ -1818,9 +1821,11 @@ int __sys_connect_file(struct file *file, struct sockaddr_storage *address,
 	struct socket *sock;
 	int err;
 
-	sock = sock_from_file(file, &err);
-	if (!sock)
+	sock = sock_from_file(file);
+	if (!sock) {
+		err = -ENOTSOCK;
 		goto out;
+	}
 
 	err =
 	    security_socket_connect(sock, (struct sockaddr *)address, addrlen);
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 310cfc68875a..ac4a317038f1 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -564,12 +564,12 @@ static int xsk_recvmsg(struct socket *sock, struct msghdr *m, size_t len, int fl
 	struct sock *sk = sock->sk;
 	struct xdp_sock *xs = xdp_sk(sk);
 
+	if (unlikely(!xsk_is_bound(xs)))
+		return -ENXIO;
 	if (unlikely(!(xs->dev->flags & IFF_UP)))
 		return -ENETDOWN;
 	if (unlikely(!xs->rx))
 		return -ENOBUFS;
-	if (unlikely(!xsk_is_bound(xs)))
-		return -ENXIO;
 	if (unlikely(need_wait))
 		return -EOPNOTSUPP;
 
diff --git a/samples/bpf/xdpsock_user.c b/samples/bpf/xdpsock_user.c
index 568f9815bb1b..db0cb73513a5 100644
--- a/samples/bpf/xdpsock_user.c
+++ b/samples/bpf/xdpsock_user.c
@@ -1275,6 +1275,8 @@ static void tx_only(struct xsk_socket_info *xsk, u32 *frame_nb, int batch_size)
 	while (xsk_ring_prod__reserve(&xsk->tx, batch_size, &idx) <
 				      batch_size) {
 		complete_tx_only(xsk, batch_size);
+		if (benchmark_done)
+			return;
 	}
 
 	for (i = 0; i < batch_size; i++) {
diff --git a/scripts/bpf_helpers_doc.py b/scripts/bpf_helpers_doc.py
index 8b829748d488..867ada23281c 100755
--- a/scripts/bpf_helpers_doc.py
+++ b/scripts/bpf_helpers_doc.py
@@ -437,6 +437,8 @@ class PrinterHelpers(Printer):
             'struct path',
             'struct btf_ptr',
             'struct inode',
+            'struct socket',
+            'struct file',
     ]
     known_types = {
             '...',
@@ -482,6 +484,8 @@ class PrinterHelpers(Printer):
             'struct path',
             'struct btf_ptr',
             'struct inode',
+            'struct socket',
+            'struct file',
     }
     mapped_types = {
             'u8': '__u8',
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 7e9931b6c735..77d7c1bb2923 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3822,6 +3822,14 @@ union bpf_attr {
  *		The **hash_algo** is returned on success,
  *		**-EOPNOTSUP** if IMA is disabled or **-EINVAL** if
  *		invalid arguments are passed.
+ *
+ * struct socket *bpf_sock_from_file(struct file *file)
+ *	Description
+ *		If the given file represents a socket, returns the associated
+ *		socket.
+ *	Return
+ *		A pointer to a struct socket on success or NULL if the file is
+ *		not a socket.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -3986,6 +3994,7 @@ union bpf_attr {
 	FN(bprm_opts_set),		\
 	FN(ktime_get_coarse_ns),	\
 	FN(ima_inode_hash),		\
+	FN(sock_from_file),		\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 9be88a90a4aa..6ae748f6ea11 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2518,7 +2518,7 @@ static int bpf_object__finalize_btf(struct bpf_object *obj)
 	return 0;
 }
 
-static inline bool libbpf_prog_needs_vmlinux_btf(struct bpf_program *prog)
+static bool prog_needs_vmlinux_btf(struct bpf_program *prog)
 {
 	if (prog->type == BPF_PROG_TYPE_STRUCT_OPS ||
 	    prog->type == BPF_PROG_TYPE_LSM)
@@ -2533,37 +2533,43 @@ static inline bool libbpf_prog_needs_vmlinux_btf(struct bpf_program *prog)
 	return false;
 }
 
-static int bpf_object__load_vmlinux_btf(struct bpf_object *obj)
+static bool obj_needs_vmlinux_btf(const struct bpf_object *obj)
 {
-	bool need_vmlinux_btf = false;
 	struct bpf_program *prog;
-	int i, err;
+	int i;
 
 	/* CO-RE relocations need kernel BTF */
 	if (obj->btf_ext && obj->btf_ext->core_relo_info.len)
-		need_vmlinux_btf = true;
+		return true;
 
 	/* Support for typed ksyms needs kernel BTF */
 	for (i = 0; i < obj->nr_extern; i++) {
 		const struct extern_desc *ext;
 
 		ext = &obj->externs[i];
-		if (ext->type == EXT_KSYM && ext->ksym.type_id) {
-			need_vmlinux_btf = true;
-			break;
-		}
+		if (ext->type == EXT_KSYM && ext->ksym.type_id)
+			return true;
 	}
 
 	bpf_object__for_each_program(prog, obj) {
 		if (!prog->load)
 			continue;
-		if (libbpf_prog_needs_vmlinux_btf(prog)) {
-			need_vmlinux_btf = true;
-			break;
-		}
+		if (prog_needs_vmlinux_btf(prog))
+			return true;
 	}
 
-	if (!need_vmlinux_btf)
+	return false;
+}
+
+static int bpf_object__load_vmlinux_btf(struct bpf_object *obj, bool force)
+{
+	int err;
+
+	/* btf_vmlinux could be loaded earlier */
+	if (obj->btf_vmlinux)
+		return 0;
+
+	if (!force && !obj_needs_vmlinux_btf(obj))
 		return 0;
 
 	obj->btf_vmlinux = libbpf_find_kernel_btf();
@@ -7475,7 +7481,7 @@ int bpf_object__load_xattr(struct bpf_object_load_attr *attr)
 	}
 
 	err = bpf_object__probe_loading(obj);
-	err = err ? : bpf_object__load_vmlinux_btf(obj);
+	err = err ? : bpf_object__load_vmlinux_btf(obj, false);
 	err = err ? : bpf_object__resolve_externs(obj, obj->kconfig);
 	err = err ? : bpf_object__sanitize_and_load_btf(obj);
 	err = err ? : bpf_object__sanitize_maps(obj);
@@ -10870,23 +10876,33 @@ int bpf_program__set_attach_target(struct bpf_program *prog,
 				   int attach_prog_fd,
 				   const char *attach_func_name)
 {
-	int btf_id;
+	int btf_obj_fd = 0, btf_id = 0, err;
 
 	if (!prog || attach_prog_fd < 0 || !attach_func_name)
 		return -EINVAL;
 
-	if (attach_prog_fd)
+	if (prog->obj->loaded)
+		return -EINVAL;
+
+	if (attach_prog_fd) {
 		btf_id = libbpf_find_prog_btf_id(attach_func_name,
 						 attach_prog_fd);
-	else
-		btf_id = libbpf_find_vmlinux_btf_id(attach_func_name,
-						    prog->expected_attach_type);
-
-	if (btf_id < 0)
-		return btf_id;
+		if (btf_id < 0)
+			return btf_id;
+	} else {
+		/* load btf_vmlinux, if not yet */
+		err = bpf_object__load_vmlinux_btf(prog->obj, true);
+		if (err)
+			return err;
+		err = find_kernel_btf_id(prog->obj, attach_func_name,
+					 prog->expected_attach_type,
+					 &btf_obj_fd, &btf_id);
+		if (err)
+			return err;
+	}
 
 	prog->attach_btf_id = btf_id;
-	prog->attach_btf_obj_fd = 0;
+	prog->attach_btf_obj_fd = btf_obj_fd;
 	prog->attach_prog_fd = attach_prog_fd;
 	return 0;
 }
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 6909ee81113a..3c35eb401931 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -536,6 +536,7 @@ LIBBPF_API int ring_buffer__add(struct ring_buffer *rb, int map_fd,
 				ring_buffer_sample_fn sample_cb, void *ctx);
 LIBBPF_API int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms);
 LIBBPF_API int ring_buffer__consume(struct ring_buffer *rb);
+LIBBPF_API int ring_buffer__epoll_fd(const struct ring_buffer *rb);
 
 /* Perf buffer APIs */
 struct perf_buffer;
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 7c4126542e2b..1c0fd2dd233a 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -346,6 +346,7 @@ LIBBPF_0.3.0 {
 		btf__parse_split;
 		btf__new_empty_split;
 		btf__new_split;
+		ring_buffer__epoll_fd;
 		xsk_setup_xdp_prog;
 		xsk_socket__update_xskmap;
 } LIBBPF_0.2.0;
diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
index 98537ff2679e..8caaafe7e312 100644
--- a/tools/lib/bpf/ringbuf.c
+++ b/tools/lib/bpf/ringbuf.c
@@ -282,3 +282,9 @@ int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms)
 	}
 	return cnt < 0 ? -errno : res;
 }
+
+/* Get an fd that can be used to sleep until data is available in the ring(s) */
+int ring_buffer__epoll_fd(const struct ring_buffer *rb)
+{
+	return rb->epoll_fd;
+}
diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore
index 752d8edddc66..f5b7ef93618c 100644
--- a/tools/testing/selftests/bpf/.gitignore
+++ b/tools/testing/selftests/bpf/.gitignore
@@ -36,3 +36,4 @@ test_cpp
 /runqslower
 /bench
 *.ko
+xdpxceiver
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index ac25ba5d0d6c..8c33e999319a 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -19,7 +19,6 @@ ifneq ($(wildcard $(GENHDR)),)
 endif
 
 CLANG		?= clang
-LLC		?= llc
 LLVM_OBJCOPY	?= llvm-objcopy
 BPF_GCC		?= $(shell command -v bpf-gcc;)
 SAN_CFLAGS	?=
@@ -46,7 +45,8 @@ endif
 
 TEST_GEN_FILES =
 TEST_FILES = test_lwt_ip_encap.o \
-	test_tc_edt.o
+	test_tc_edt.o \
+	xsk_prereqs.sh
 
 # Order correspond to 'make run_tests' order
 TEST_PROGS := test_kmod.sh \
@@ -70,17 +70,17 @@ TEST_PROGS := test_kmod.sh \
 	test_bpftool_build.sh \
 	test_bpftool.sh \
 	test_bpftool_metadata.sh \
+	test_xsk.sh
 
 TEST_PROGS_EXTENDED := with_addr.sh \
 	with_tunnels.sh