bpf-for-netdev

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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Daniel Borkmann says:

====================
pull-request: bpf 2023-03-06

We've added 8 non-merge commits during the last 7 day(s) which contain
a total of 9 files changed, 64 insertions(+), 18 deletions(-).

The main changes are:

1) Fix BTF resolver for DATASEC sections when a VAR points at a modifier,
   that is, keep resolving such instances instead of bailing out,
   from Lorenz Bauer.

2) Fix BPF test framework with regards to xdp_frame info misplacement
   in the "live packet" code, from Alexander Lobakin.

3) Fix an infinite loop in BPF sockmap code for TCP/UDP/AF_UNIX,
   from Liu Jian.

4) Fix a build error for riscv BPF JIT under PERF_EVENTS=n,
   from Randy Dunlap.

5) Several BPF doc fixes with either broken links or external instead
   of internal doc links, from Bagas Sanjaya.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  selftests/bpf: check that modifier resolves after pointer
  btf: fix resolving BTF_KIND_VAR after ARRAY, STRUCT, UNION, PTR
  bpf, test_run: fix &xdp_frame misplacement for LIVE_FRAMES
  bpf, doc: Link to submitting-patches.rst for general patch submission info
  bpf, doc: Do not link to docs.kernel.org for kselftest link
  bpf, sockmap: Fix an infinite loop error when len is 0 in tcp_bpf_recvmsg_parser()
  riscv, bpf: Fix patch_text implicit declaration
  bpf, docs: Fix link to BTF doc
====================

Link: https://lore.kernel.org/r/20230306215944.11981-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/bpf/bpf_devel_QA.rst

@@ -7,8 +7,8 @@ workflows related to reporting bugs, submitting patches, and queueing
 patches for stable kernels.
 
 For general information about submitting patches, please refer to
-`Documentation/process/`_. This document only describes additional specifics
-related to BPF.
+Documentation/process/submitting-patches.rst. This document only describes
+additional specifics related to BPF.
 
 .. contents::
     :local:
@@ -461,15 +461,15 @@ needed::
 
   $ sudo make run_tests
 
-See the kernels selftest `Documentation/dev-tools/kselftest.rst`_
-document for further documentation.
+See :doc:`kernel selftest documentation </dev-tools/kselftest>`
+for details.
 
 To maximize the number of tests passing, the .config of the kernel
 under test should match the config file fragment in
 tools/testing/selftests/bpf as closely as possible.
 
 Finally to ensure support for latest BPF Type Format features -
-discussed in `Documentation/bpf/btf.rst`_ - pahole version 1.16
+discussed in Documentation/bpf/btf.rst - pahole version 1.16
 is required for kernels built with CONFIG_DEBUG_INFO_BTF=y.
 pahole is delivered in the dwarves package or can be built
 from source at
@@ -684,12 +684,8 @@ when:
 
 
 .. Links
-.. _Documentation/process/: https://www.kernel.org/doc/html/latest/process/
 .. _netdev-FAQ: Documentation/process/maintainer-netdev.rst
 .. _selftests:
    https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/
-.. _Documentation/dev-tools/kselftest.rst:
-   https://www.kernel.org/doc/html/latest/dev-tools/kselftest.html
-.. _Documentation/bpf/btf.rst: btf.rst
 
 Happy BPF hacking!

arch/riscv/net/bpf_jit_comp64.c

@@ -10,6 +10,7 @@
 #include <linux/filter.h>
 #include <linux/memory.h>
 #include <linux/stop_machine.h>
+#include <asm/patch.h>
 #include "bpf_jit.h"
 
 #define RV_REG_TCC RV_REG_A6

kernel/bpf/btf.c

@@ -4569,6 +4569,7 @@ static int btf_datasec_resolve(struct btf_verifier_env *env,
 	struct btf *btf = env->btf;
 	u16 i;
 
+	env->resolve_mode = RESOLVE_TBD;
 	for_each_vsi_from(i, v->next_member, v->t, vsi) {
 		u32 var_type_id = vsi->type, type_id, type_size = 0;
 		const struct btf_type *var_type = btf_type_by_id(env->btf,

net/bpf/test_run.c

@@ -97,8 +97,11 @@ reset:
 struct xdp_page_head {
 	struct xdp_buff orig_ctx;
 	struct xdp_buff ctx;
-	struct xdp_frame frm;
-	u8 data[];
+	union {
+		/* ::data_hard_start starts here */
+		DECLARE_FLEX_ARRAY(struct xdp_frame, frame);
+		DECLARE_FLEX_ARRAY(u8, data);
+	};
 };
 
 struct xdp_test_data {
@@ -113,6 +116,10 @@ struct xdp_test_data {
 	u32 frame_cnt;
 };
 
+/* tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c:%MAX_PKT_SIZE
+ * must be updated accordingly this gets changed, otherwise BPF selftests
+ * will fail.
+ */
 #define TEST_XDP_FRAME_SIZE (PAGE_SIZE - sizeof(struct xdp_page_head))
 #define TEST_XDP_MAX_BATCH 256
 
@@ -132,8 +139,8 @@ static void xdp_test_run_init_page(struct page *page, void *arg)
 	headroom -= meta_len;
 
 	new_ctx = &head->ctx;
-	frm = &head->frm;
-	data = &head->data;
+	frm = head->frame;
+	data = head->data;
 	memcpy(data + headroom, orig_ctx->data_meta, frm_len);
 
 	xdp_init_buff(new_ctx, TEST_XDP_FRAME_SIZE, &xdp->rxq);
@@ -223,7 +230,7 @@ static void reset_ctx(struct xdp_page_head *head)
 	head->ctx.data = head->orig_ctx.data;
 	head->ctx.data_meta = head->orig_ctx.data_meta;
 	head->ctx.data_end = head->orig_ctx.data_end;
-	xdp_update_frame_from_buff(&head->ctx, &head->frm);
+	xdp_update_frame_from_buff(&head->ctx, head->frame);
 }
 
 static int xdp_recv_frames(struct xdp_frame **frames, int nframes,
@@ -285,7 +292,7 @@ static int xdp_test_run_batch(struct xdp_test_data *xdp, struct bpf_prog *prog,
 		head = phys_to_virt(page_to_phys(page));
 		reset_ctx(head);
 		ctx = &head->ctx;
-		frm = &head->frm;
+		frm = head->frame;
 		xdp->frame_cnt++;
 
 		act = bpf_prog_run_xdp(prog, ctx);

net/ipv4/tcp_bpf.c

@@ -186,6 +186,9 @@ static int tcp_bpf_recvmsg_parser(struct sock *sk,
 	if (unlikely(flags & MSG_ERRQUEUE))
 		return inet_recv_error(sk, msg, len, addr_len);
 
+	if (!len)
+		return 0;
+
 	psock = sk_psock_get(sk);
 	if (unlikely(!psock))
 		return tcp_recvmsg(sk, msg, len, flags, addr_len);
@@ -244,6 +247,9 @@ static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 	if (unlikely(flags & MSG_ERRQUEUE))
 		return inet_recv_error(sk, msg, len, addr_len);
 
+	if (!len)
+		return 0;
+
 	psock = sk_psock_get(sk);
 	if (unlikely(!psock))
 		return tcp_recvmsg(sk, msg, len, flags, addr_len);

net/ipv4/udp_bpf.c

@@ -68,6 +68,9 @@ static int udp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 	if (unlikely(flags & MSG_ERRQUEUE))
 		return inet_recv_error(sk, msg, len, addr_len);
 
+	if (!len)
+		return 0;
+
 	psock = sk_psock_get(sk);
 	if (unlikely(!psock))
 		return sk_udp_recvmsg(sk, msg, len, flags, addr_len);

net/unix/unix_bpf.c

@@ -54,6 +54,9 @@ static int unix_bpf_recvmsg(struct sock *sk, struct msghdr *msg,
 	struct sk_psock *psock;
 	int copied;
 
+	if (!len)
+		return 0;
+
 	psock = sk_psock_get(sk);
 	if (unlikely(!psock))
 		return __unix_recvmsg(sk, msg, len, flags);

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

@@ -879,6 +879,34 @@ static struct btf_raw_test raw_tests[] = {
 	.btf_load_err = true,
 	.err_str = "Invalid elem",
 },
+{
+	.descr = "var after datasec, ptr followed by modifier",
+	.raw_types = {
+		/* .bss section */				/* [1] */
+		BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 2),
+			sizeof(void*)+4),
+		BTF_VAR_SECINFO_ENC(4, 0, sizeof(void*)),
+		BTF_VAR_SECINFO_ENC(6, sizeof(void*), 4),
+		/* int */					/* [2] */
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),
+		/* int* */					/* [3] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 2),
+		BTF_VAR_ENC(NAME_TBD, 3, 0),			/* [4] */
+		/* const int */					/* [5] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_CONST, 0, 0), 2),
+		BTF_VAR_ENC(NAME_TBD, 5, 0),			/* [6] */
+		BTF_END_RAW,
+	},
+	.str_sec = "\0a\0b\0c\0",
+	.str_sec_size = sizeof("\0a\0b\0c\0"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = ".bss",
+	.key_size = sizeof(int),
+	.value_size = sizeof(void*)+4,
+	.key_type_id = 0,
+	.value_type_id = 1,
+	.max_entries = 1,
+},
 /* Test member exceeds the size of struct.
  *
  * struct A {

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

@@ -65,12 +65,13 @@ static int attach_tc_prog(struct bpf_tc_hook *hook, int fd)
 }
 
 /* The maximum permissible size is: PAGE_SIZE - sizeof(struct xdp_page_head) -
- * sizeof(struct skb_shared_info) - XDP_PACKET_HEADROOM = 3368 bytes
+ * SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) - XDP_PACKET_HEADROOM =
+ * 3408 bytes for 64-byte cacheline and 3216 for 256-byte one.
  */
 #if defined(__s390x__)
-#define MAX_PKT_SIZE 3176
+#define MAX_PKT_SIZE 3216
 #else
-#define MAX_PKT_SIZE 3368
+#define MAX_PKT_SIZE 3408
 #endif
 static void test_max_pkt_size(int fd)
 {