Merge branch 'libbpf:master' into master

Syncing latest libbpf commits from kernel repository.
Baseline bpf-next commit:   c628747cc8800cf6d33d09f7f42c8b6f91e64dc7
Checkpoint bpf-next commit: a3e7e6b17946f48badce98d7ac360678a0ea7393
Baseline bpf commit:        496720b7cfb6574a8f6f4d434f23e3d1e6cfaeb9
Checkpoint bpf commit:      496720b7cfb6574a8f6f4d434f23e3d1e6cfaeb9

Andrii Nakryiko (1):
  libbpf: Fix realloc API handling in zero-sized edge cases

John Sanpe (1):
  libbpf: Remove HASHMAP_INIT static initialization helper

 src/hashmap.h | 10 ----------
 src/libbpf.c  | 15 ++++++++++++---
 src/usdt.c    |  5 ++++-
 3 files changed, 16 insertions(+), 14 deletions(-)

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

.gitattributes

@@ -1 +1 @@
-assets/ export-ignore
+assets/** export-ignore

.github/actions/build-selftests/build_selftests.sh

@@ -40,6 +40,7 @@ else
 fi
 
 cd ${REPO_ROOT}/${REPO_PATH}
+make headers
 make \
 	CLANG=clang-${LLVM_VERSION} \
 	LLC=llc-${LLVM_VERSION} \

BPF-CHECKPOINT-COMMIT

@@ -1 +1 @@
-71b547f561247897a0a14f3082730156c0533fed
+496720b7cfb6574a8f6f4d434f23e3d1e6cfaeb9

CHECKPOINT-COMMIT

@@ -1 +1 @@
-2ddade322925641ee2a75f13665c51f2e74d7791
+a3e7e6b17946f48badce98d7ac360678a0ea7393

ci/diffs/0001-selftests-bpf-Check-whether-to-run-selftest.patch

@@ -0,0 +1,37 @@
+From ff8be5401b359e23ec2b74184034082564bac7c5 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Daniel=20M=C3=BCller?= <deso@posteo.net>
+Date: Thu, 25 May 2023 16:04:20 -0700
+Subject: [PATCH] selftests/bpf: Check whether to run selftest
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+The sockopt test invokes test__start_subtest and then unconditionally
+asserts the success. That means that even if deny-listed, any test will
+still run and potentially fail.
+Evaluate the return value of test__start_subtest() to achieve the
+desired behavior, as other tests do.
+
+Signed-off-by: Daniel Müller <deso@posteo.net>
+---
+ tools/testing/selftests/bpf/prog_tests/sockopt.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/tools/testing/selftests/bpf/prog_tests/sockopt.c b/tools/testing/selftests/bpf/prog_tests/sockopt.c
+index 33dd45..9e6a5e 100644
+--- a/tools/testing/selftests/bpf/prog_tests/sockopt.c
++++ b/tools/testing/selftests/bpf/prog_tests/sockopt.c
+@@ -1060,7 +1060,9 @@ void test_sockopt(void)
+ 		return;
+ 
+ 	for (i = 0; i < ARRAY_SIZE(tests); i++) {
+-		test__start_subtest(tests[i].descr);
++		if (!test__start_subtest(tests[i].descr))
++			continue;
++
+ 		ASSERT_OK(run_test(cgroup_fd, &tests[i]), tests[i].descr);
+ 	}
+ 
+-- 
+2.34.1
+

ci/diffs/0001-tracing-fprobe-Initialize-ret-valiable-to-fix-smatch.patch

@@ -0,0 +1,68 @@
+From d3484f640bc82cff459beb85a00f7ebab20f0a41 Mon Sep 17 00:00:00 2001
+From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
+Date: Sun, 9 Apr 2023 11:28:31 +0900
+Subject: [PATCH] tracing: fprobe: Initialize ret valiable to fix smatch error
+
+The commit 39d954200bf6 ("fprobe: Skip exit_handler if entry_handler returns
+!0") introduced a hidden dependency of 'ret' local variable in the
+fprobe_handler(), Smatch warns the `ret` can be accessed without
+initialization.
+
+	kernel/trace/fprobe.c:59 fprobe_handler()
+	error: uninitialized symbol 'ret'.
+
+kernel/trace/fprobe.c
+    49                 fpr->entry_ip = ip;
+    50                 if (fp->entry_data_size)
+    51                         entry_data = fpr->data;
+    52         }
+    53
+    54         if (fp->entry_handler)
+    55                 ret = fp->entry_handler(fp, ip, ftrace_get_regs(fregs), entry_data);
+
+ret is only initialized if there is an ->entry_handler
+
+    56
+    57         /* If entry_handler returns !0, nmissed is not counted. */
+    58         if (rh) {
+
+rh is only true if there is an ->exit_handler.  Presumably if you have
+and ->exit_handler that means you also have a ->entry_handler but Smatch
+is not smart enough to figure it out.
+
+--> 59                 if (ret)
+                           ^^^
+Warning here.
+
+    60                         rethook_recycle(rh);
+    61                 else
+    62                         rethook_hook(rh, ftrace_get_regs(fregs), true);
+    63         }
+    64 out:
+    65         ftrace_test_recursion_unlock(bit);
+    66 }
+
+Reported-by: Dan Carpenter <error27@gmail.com>
+Link: https://lore.kernel.org/all/85429a5c-a4b9-499e-b6c0-cbd313291c49@kili.mountain
+Fixes: 39d954200bf6 ("fprobe: Skip exit_handler if entry_handler returns !0")
+Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
+---
+ kernel/trace/fprobe.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
+index 9abb3905bc8e..293184227394 100644
+--- a/kernel/trace/fprobe.c
++++ b/kernel/trace/fprobe.c
+@@ -27,7 +27,7 @@ static void fprobe_handler(unsigned long ip, unsigned long parent_ip,
+ 	struct rethook_node *rh = NULL;
+ 	struct fprobe *fp;
+ 	void *entry_data = NULL;
+-	int bit, ret;
++	int bit, ret = 0;
+ 
+ 	fp = container_of(ops, struct fprobe, ops);
+ 	if (fprobe_disabled(fp))
+-- 
+2.34.1
+

ci/vmtest/configs/ALLOWLIST-5.5.0

@@ -35,8 +35,6 @@ signal_pending
 skeleton
 sockmap_ktls
 sockopt
-sockopt_inherit
-sockopt_multi
 spinlock
 stacktrace_map
 stacktrace_map_raw_tp

ci/vmtest/configs/DENYLIST-5.5.0

@@ -78,6 +78,8 @@ sock_fields		# v5.10+
 socket_cookie		# v5.12+
 sockmap_basic		# uses new socket fields, 5.8+
 sockmap_listen		# no listen socket supportin SOCKMAP
+sockopt/getsockopt: ignore >PAGE_SIZE optlen
+sockopt/setsockopt: ignore >PAGE_SIZE optlen
 sockopt_sk
 sockopt_qos_to_cc	# v5.15+
 stacktrace_build_id	# v5.9+

ci/vmtest/configs/DENYLIST-latest

@@ -1 +1,4 @@
 decap_sanity  # weird failure with decap_sanity_ns netns already existing, TBD
+bpf_nf/tc-bpf-ct # test consistently failing on x86: https://github.com/libbpf/libbpf/pull/698#issuecomment-1590341200
+bpf_nf/xdp-ct   # test consistently failing on x86: https://github.com/libbpf/libbpf/pull/698#issuecomment-1590341200
+kprobe_multi_bench_attach # suspected to cause crashes in CI

ci/vmtest/configs/DENYLIST-latest.s390x

@@ -1,3 +1,4 @@
 # TEMPORARY
+sockmap_listen/sockhash VSOCK test_vsock_redir
 usdt/basic                               # failing verifier due to bounds check after LLVM update
 usdt/multispec                           # same as above

ci/vmtest/run_selftests.sh

@@ -13,7 +13,7 @@ read_lists() {
 		if [[ -s "$path" ]]; then
 			cat "$path"
 		fi;
-	done) | cut -d'#' -f1 | tr -s ' \t\n' ','
+	done) | cut -d'#' -f1 | sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//' | tr -s '\n' ','
 }
 
 test_progs() {
@@ -22,7 +22,7 @@ test_progs() {
 		# "&& true" does not change the return code (it is not executed
 		# if the Python script fails), but it prevents exiting on a
 		# failure due to the "set -e".
-		./test_progs ${DENYLIST:+-d$DENYLIST} ${ALLOWLIST:+-a$ALLOWLIST} && true
+		./test_progs ${DENYLIST:+-d"$DENYLIST"} ${ALLOWLIST:+-a"$ALLOWLIST"} && true
 		echo "test_progs:$?" >> "${STATUS_FILE}"
 		foldable end test_progs
 	fi
@@ -30,7 +30,7 @@ test_progs() {
 
 test_progs_no_alu32() {
 	foldable start test_progs-no_alu32 "Testing test_progs-no_alu32"
-	./test_progs-no_alu32 ${DENYLIST:+-d$DENYLIST} ${ALLOWLIST:+-a$ALLOWLIST} && true
+	./test_progs-no_alu32 ${DENYLIST:+-d"$DENYLIST"} ${ALLOWLIST:+-a"$ALLOWLIST"} && true
 	echo "test_progs-no_alu32:$?" >> "${STATUS_FILE}"
 	foldable end test_progs-no_alu32
 }
@@ -55,6 +55,13 @@ test_verifier() {
 
 foldable end vm_init
 
+foldable start kernel_config "Kconfig"
+
+zcat /proc/config.gz
+
+foldable end kernel_config
+
+
 configs_path=/${PROJECT_NAME}/selftests/bpf
 local_configs_path=${PROJECT_NAME}/vmtest/configs
 DENYLIST=$(read_lists \

include/uapi/linux/bpf.h

@@ -986,6 +986,7 @@ enum bpf_prog_type {
 	BPF_PROG_TYPE_LSM,
 	BPF_PROG_TYPE_SK_LOOKUP,
 	BPF_PROG_TYPE_SYSCALL, /* a program that can execute syscalls */
+	BPF_PROG_TYPE_NETFILTER,
 };
 
 enum bpf_attach_type {
@@ -1034,6 +1035,7 @@ enum bpf_attach_type {
 	BPF_TRACE_KPROBE_MULTI,
 	BPF_LSM_CGROUP,
 	BPF_STRUCT_OPS,
+	BPF_NETFILTER,
 	__MAX_BPF_ATTACH_TYPE
 };
 
@@ -1050,6 +1052,7 @@ enum bpf_link_type {
 	BPF_LINK_TYPE_PERF_EVENT = 7,
 	BPF_LINK_TYPE_KPROBE_MULTI = 8,
 	BPF_LINK_TYPE_STRUCT_OPS = 9,
+	BPF_LINK_TYPE_NETFILTER = 10,
 
 	MAX_BPF_LINK_TYPE,
 };
@@ -1270,6 +1273,9 @@ enum {
 
 /* Create a map that will be registered/unregesitered by the backed bpf_link */
 	BPF_F_LINK		= (1U << 13),
+
+/* Get path from provided FD in BPF_OBJ_PIN/BPF_OBJ_GET commands */
+	BPF_F_PATH_FD		= (1U << 14),
 };
 
 /* Flags for BPF_PROG_QUERY. */
@@ -1418,6 +1424,13 @@ union bpf_attr {
 		__aligned_u64	pathname;
 		__u32		bpf_fd;
 		__u32		file_flags;
+		/* Same as dirfd in openat() syscall; see openat(2)
+		 * manpage for details of path FD and pathname semantics;
+		 * path_fd should accompanied by BPF_F_PATH_FD flag set in
+		 * file_flags field, otherwise it should be set to zero;
+		 * if BPF_F_PATH_FD flag is not set, AT_FDCWD is assumed.
+		 */
+		__s32		path_fd;
 	};
 
 	struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
@@ -1560,6 +1573,12 @@ union bpf_attr {
 				 */
 				__u64		cookie;
 			} tracing;
+			struct {
+				__u32		pf;
+				__u32		hooknum;
+				__s32		priority;
+				__u32		flags;
+			} netfilter;
 		};
 	} link_create;
 
@@ -3159,6 +3178,10 @@ union bpf_attr {
  *		**BPF_FIB_LOOKUP_DIRECT**
  *			Do a direct table lookup vs full lookup using FIB
  *			rules.
+ *		**BPF_FIB_LOOKUP_TBID**
+ *			Used with BPF_FIB_LOOKUP_DIRECT.
+ *			Use the routing table ID present in *params*->tbid
+ *			for the fib lookup.
  *		**BPF_FIB_LOOKUP_OUTPUT**
  *			Perform lookup from an egress perspective (default is
  *			ingress).
@@ -6410,6 +6433,12 @@ struct bpf_link_info {
 		struct {
 			__u32 map_id;
 		} struct_ops;
+		struct {
+			__u32 pf;
+			__u32 hooknum;
+			__s32 priority;
+			__u32 flags;
+		} netfilter;
 	};
 } __attribute__((aligned(8)));
 
@@ -6807,6 +6836,7 @@ enum {
 	BPF_FIB_LOOKUP_DIRECT  = (1U << 0),
 	BPF_FIB_LOOKUP_OUTPUT  = (1U << 1),
 	BPF_FIB_LOOKUP_SKIP_NEIGH = (1U << 2),
+	BPF_FIB_LOOKUP_TBID    = (1U << 3),
 };
 
 enum {
@@ -6867,9 +6897,19 @@ struct bpf_fib_lookup {
 		__u32		ipv6_dst[4];  /* in6_addr; network order */
 	};
 
-	/* output */
+	union {
-	__be16	h_vlan_proto;
+		struct {
-	__be16	h_vlan_TCI;
+			/* output */
+			__be16	h_vlan_proto;
+			__be16	h_vlan_TCI;
+		};
+		/* input: when accompanied with the
+		 * 'BPF_FIB_LOOKUP_DIRECT | BPF_FIB_LOOKUP_TBID` flags, a
+		 * specific routing table to use for the fib lookup.
+		 */
+		__u32	tbid;
+	};
+
 	__u8	smac[6];     /* ETH_ALEN */
 	__u8	dmac[6];     /* ETH_ALEN */
 };

scripts/build-fuzzers.sh

@@ -44,11 +44,11 @@ rm -rf elfutils
 git clone git://sourceware.org/git/elfutils.git
 (
 cd elfutils
-git checkout e9f3045caa5c4498f371383e5519151942d48b6d
+git checkout 67a187d4c1790058fc7fd218317851cb68bb087c
 git log --oneline -1
 
 # ASan isn't compatible with -Wl,--no-undefined: https://github.com/google/sanitizers/issues/380
-find -name Makefile.am | xargs sed -i 's/,--no-undefined//'
+sed -i 's/^\(NO_UNDEFINED=\).*/\1/' configure.ac
 
 # ASan isn't compatible with -Wl,-z,defs either:
 # https://clang.llvm.org/docs/AddressSanitizer.html#usage
@@ -62,6 +62,7 @@ fi
 
 autoreconf -i -f
 if ! ./configure --enable-maintainer-mode --disable-debuginfod --disable-libdebuginfod \
+            --disable-demangler --without-bzlib --without-lzma --without-zstd \
 	    CC="$CC" CFLAGS="-Wno-error $CFLAGS" CXX="$CXX" CXXFLAGS="-Wno-error $CXXFLAGS" LDFLAGS="$CFLAGS"; then
     cat config.log
     exit 1

src/Makefile

@@ -9,7 +9,7 @@ else
 endif
 
 LIBBPF_MAJOR_VERSION := 1
-LIBBPF_MINOR_VERSION := 2
+LIBBPF_MINOR_VERSION := 3
 LIBBPF_PATCH_VERSION := 0
 LIBBPF_VERSION := $(LIBBPF_MAJOR_VERSION).$(LIBBPF_MINOR_VERSION).$(LIBBPF_PATCH_VERSION)
 LIBBPF_MAJMIN_VERSION := $(LIBBPF_MAJOR_VERSION).$(LIBBPF_MINOR_VERSION).0

src/bpf.c

@@ -572,20 +572,30 @@ int bpf_map_update_batch(int fd, const void *keys, const void *values, __u32 *co
 				    (void *)keys, (void *)values, count, opts);
 }
 
-int bpf_obj_pin(int fd, const char *pathname)
+int bpf_obj_pin_opts(int fd, const char *pathname, const struct bpf_obj_pin_opts *opts)
 {
-	const size_t attr_sz = offsetofend(union bpf_attr, file_flags);
+	const size_t attr_sz = offsetofend(union bpf_attr, path_fd);
 	union bpf_attr attr;
 	int ret;
 
+	if (!OPTS_VALID(opts, bpf_obj_pin_opts))
+		return libbpf_err(-EINVAL);
+
 	memset(&attr, 0, attr_sz);
+	attr.path_fd = OPTS_GET(opts, path_fd, 0);
 	attr.pathname = ptr_to_u64((void *)pathname);
+	attr.file_flags = OPTS_GET(opts, file_flags, 0);
 	attr.bpf_fd = fd;
 
 	ret = sys_bpf(BPF_OBJ_PIN, &attr, attr_sz);
 	return libbpf_err_errno(ret);
 }
 
+int bpf_obj_pin(int fd, const char *pathname)
+{
+	return bpf_obj_pin_opts(fd, pathname, NULL);
+}
+
 int bpf_obj_get(const char *pathname)
 {
 	return bpf_obj_get_opts(pathname, NULL);
@@ -593,7 +603,7 @@ int bpf_obj_get(const char *pathname)
 
 int bpf_obj_get_opts(const char *pathname, const struct bpf_obj_get_opts *opts)
 {
-	const size_t attr_sz = offsetofend(union bpf_attr, file_flags);
+	const size_t attr_sz = offsetofend(union bpf_attr, path_fd);
 	union bpf_attr attr;
 	int fd;
 
@@ -601,6 +611,7 @@ int bpf_obj_get_opts(const char *pathname, const struct bpf_obj_get_opts *opts)
 		return libbpf_err(-EINVAL);
 
 	memset(&attr, 0, attr_sz);
+	attr.path_fd = OPTS_GET(opts, path_fd, 0);
 	attr.pathname = ptr_to_u64((void *)pathname);
 	attr.file_flags = OPTS_GET(opts, file_flags, 0);
 
@@ -730,6 +741,14 @@ int bpf_link_create(int prog_fd, int target_fd,
 		if (!OPTS_ZEROED(opts, tracing))
 			return libbpf_err(-EINVAL);
 		break;
+	case BPF_NETFILTER:
+		attr.link_create.netfilter.pf = OPTS_GET(opts, netfilter.pf, 0);
+		attr.link_create.netfilter.hooknum = OPTS_GET(opts, netfilter.hooknum, 0);
+		attr.link_create.netfilter.priority = OPTS_GET(opts, netfilter.priority, 0);
+		attr.link_create.netfilter.flags = OPTS_GET(opts, netfilter.flags, 0);
+		if (!OPTS_ZEROED(opts, netfilter))
+			return libbpf_err(-EINVAL);
+		break;
 	default:
 		if (!OPTS_ZEROED(opts, flags))
 			return libbpf_err(-EINVAL);

src/bpf.h

@@ -284,16 +284,30 @@ LIBBPF_API int bpf_map_update_batch(int fd, const void *keys, const void *values
 				    __u32 *count,
 				    const struct bpf_map_batch_opts *opts);
 
+struct bpf_obj_pin_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+
+	__u32 file_flags;
+	int path_fd;
+
+	size_t :0;
+};
+#define bpf_obj_pin_opts__last_field path_fd
+
+LIBBPF_API int bpf_obj_pin(int fd, const char *pathname);
+LIBBPF_API int bpf_obj_pin_opts(int fd, const char *pathname,
+				const struct bpf_obj_pin_opts *opts);
+
 struct bpf_obj_get_opts {
 	size_t sz; /* size of this struct for forward/backward compatibility */
 
 	__u32 file_flags;
+	int path_fd;
 
 	size_t :0;
 };
-#define bpf_obj_get_opts__last_field file_flags
+#define bpf_obj_get_opts__last_field path_fd
 
-LIBBPF_API int bpf_obj_pin(int fd, const char *pathname);
 LIBBPF_API int bpf_obj_get(const char *pathname);
 LIBBPF_API int bpf_obj_get_opts(const char *pathname,
 				const struct bpf_obj_get_opts *opts);
@@ -335,6 +349,12 @@ struct bpf_link_create_opts {
 		struct {
 			__u64 cookie;
 		} tracing;
+		struct {
+			__u32 pf;
+			__u32 hooknum;
+			__s32 priority;
+			__u32 flags;
+		} netfilter;
 	};
 	size_t :0;
 };

src/bpf_helper_defs.h

@@ -1832,6 +1832,10 @@ static long (*bpf_skb_load_bytes_relative)(const void *skb, __u32 offset, void *
  * 	**BPF_FIB_LOOKUP_DIRECT**
  * 		Do a direct table lookup vs full lookup using FIB
  * 		rules.
+ * 	**BPF_FIB_LOOKUP_TBID**
+ * 		Used with BPF_FIB_LOOKUP_DIRECT.
+ * 		Use the routing table ID present in *params*->tbid
+ * 		for the fib lookup.
  * 	**BPF_FIB_LOOKUP_OUTPUT**
  * 		Perform lookup from an egress perspective (default is
  * 		ingress).

src/bpf_helpers.h

@@ -77,16 +77,21 @@
 /*
  * Helper macros to manipulate data structures
  */
-#ifndef offsetof
+
-#define offsetof(TYPE, MEMBER)	((unsigned long)&((TYPE *)0)->MEMBER)
+/* offsetof() definition that uses __builtin_offset() might not preserve field
-#endif
+ * offset CO-RE relocation properly, so force-redefine offsetof() using
-#ifndef container_of
+ * old-school approach which works with CO-RE correctly
+ */
+#undef offsetof
+#define offsetof(type, member)	((unsigned long)&((type *)0)->member)
+
+/* redefined container_of() to ensure we use the above offsetof() macro */
+#undef container_of
 #define container_of(ptr, type, member)				\
 	({							\
 		void *__mptr = (void *)(ptr);			\
 		((type *)(__mptr - offsetof(type, member)));	\
 	})
-#endif
 
 /*
  * Compiler (optimization) barrier.

src/bpf_tracing.h

@@ -351,6 +351,7 @@ struct pt_regs___arm64 {
  * https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-cc.adoc#risc-v-calling-conventions
  */
 
+/* riscv provides struct user_regs_struct instead of struct pt_regs to userspace */
 #define __PT_REGS_CAST(x) ((const struct user_regs_struct *)(x))
 #define __PT_PARM1_REG a0
 #define __PT_PARM2_REG a1
@@ -383,7 +384,7 @@ struct pt_regs___arm64 {
  * https://raw.githubusercontent.com/wiki/foss-for-synopsys-dwc-arc-processors/toolchain/files/ARCv2_ABI.pdf
  */
 
-/* arc provides struct user_pt_regs instead of struct pt_regs to userspace */
+/* arc provides struct user_regs_struct instead of struct pt_regs to userspace */
 #define __PT_REGS_CAST(x) ((const struct user_regs_struct *)(x))
 #define __PT_PARM1_REG scratch.r0
 #define __PT_PARM2_REG scratch.r1

src/btf.c

@@ -1064,7 +1064,7 @@ static struct btf *btf_parse_raw(const char *path, struct btf *base_btf)
 	int err = 0;
 	long sz;
 
-	f = fopen(path, "rb");
+	f = fopen(path, "rbe");
 	if (!f) {
 		err = -errno;
 		goto err_out;

src/btf_dump.c

@@ -2250,9 +2250,25 @@ static int btf_dump_type_data_check_overflow(struct btf_dump *d,
 					     const struct btf_type *t,
 					     __u32 id,
 					     const void *data,
-					     __u8 bits_offset)
+					     __u8 bits_offset,
+					     __u8 bit_sz)
 {
-	__s64 size = btf__resolve_size(d->btf, id);
+	__s64 size;
+
+	if (bit_sz) {
+		/* bits_offset is at most 7. bit_sz is at most 128. */
+		__u8 nr_bytes = (bits_offset + bit_sz + 7) / 8;
+
+		/* When bit_sz is non zero, it is called from
+		 * btf_dump_struct_data() where it only cares about
+		 * negative error value.
+		 * Return nr_bytes in success case to make it
+		 * consistent as the regular integer case below.
+		 */
+		return data + nr_bytes > d->typed_dump->data_end ? -E2BIG : nr_bytes;
+	}
+
+	size = btf__resolve_size(d->btf, id);
 
 	if (size < 0 || size >= INT_MAX) {
 		pr_warn("unexpected size [%zu] for id [%u]\n",
@@ -2407,7 +2423,7 @@ static int btf_dump_dump_type_data(struct btf_dump *d,
 {
 	int size, err = 0;
 
-	size = btf_dump_type_data_check_overflow(d, t, id, data, bits_offset);
+	size = btf_dump_type_data_check_overflow(d, t, id, data, bits_offset, bit_sz);
 	if (size < 0)
 		return size;
 	err = btf_dump_type_data_check_zero(d, t, id, data, bits_offset, bit_sz);

src/gen_loader.c

@@ -703,17 +703,17 @@ static void emit_relo_kfunc_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo
 	/* obtain fd in BPF_REG_9 */
 	emit(gen, BPF_MOV64_REG(BPF_REG_9, BPF_REG_7));
 	emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_9, 32));
-	/* jump to fd_array store if fd denotes module BTF */
+	/* load fd_array slot pointer */
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, blob_fd_array_off(gen, btf_fd_idx)));
+	/* store BTF fd in slot, 0 for vmlinux */
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_9, 0));
+	/* jump to insn[insn_idx].off store if fd denotes module BTF */
 	emit(gen, BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 0, 2));
 	/* set the default value for off */
 	emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), 0));
 	/* skip BTF fd store for vmlinux BTF */
-	emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 4));
+	emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 1));
-	/* load fd_array slot pointer */
-	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
-					 0, 0, 0, blob_fd_array_off(gen, btf_fd_idx)));
-	/* store BTF fd in slot */
-	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_9, 0));
 	/* store index into insn[insn_idx].off */
 	emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), btf_fd_idx));
 log:

src/hashmap.h

@@ -80,16 +80,6 @@ struct hashmap {
 	size_t sz;
 };
 
-#define HASHMAP_INIT(hash_fn, equal_fn, ctx) {	\
-	.hash_fn = (hash_fn),			\
-	.equal_fn = (equal_fn),			\
-	.ctx = (ctx),				\
-	.buckets = NULL,			\
-	.cap = 0,				\
-	.cap_bits = 0,				\
-	.sz = 0,				\
-}
-
 void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
 		   hashmap_equal_fn equal_fn, void *ctx);
 struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,

src/libbpf.c

@@ -117,6 +117,7 @@ static const char * const attach_type_name[] = {
 	[BPF_PERF_EVENT]		= "perf_event",
 	[BPF_TRACE_KPROBE_MULTI]	= "trace_kprobe_multi",
 	[BPF_STRUCT_OPS]		= "struct_ops",
+	[BPF_NETFILTER]			= "netfilter",
 };
 
 static const char * const link_type_name[] = {
@@ -130,6 +131,7 @@ static const char * const link_type_name[] = {
 	[BPF_LINK_TYPE_PERF_EVENT]		= "perf_event",
 	[BPF_LINK_TYPE_KPROBE_MULTI]		= "kprobe_multi",
 	[BPF_LINK_TYPE_STRUCT_OPS]		= "struct_ops",
+	[BPF_LINK_TYPE_NETFILTER]		= "netfilter",
 };
 
 static const char * const map_type_name[] = {
@@ -201,6 +203,7 @@ static const char * const prog_type_name[] = {
 	[BPF_PROG_TYPE_LSM]			= "lsm",
 	[BPF_PROG_TYPE_SK_LOOKUP]		= "sk_lookup",
 	[BPF_PROG_TYPE_SYSCALL]			= "syscall",
+	[BPF_PROG_TYPE_NETFILTER]		= "netfilter",
 };
 
 static int __base_pr(enum libbpf_print_level level, const char *format,
@@ -1359,7 +1362,7 @@ static int bpf_object__elf_init(struct bpf_object *obj)
 		goto errout;
 	}
 
-	/* Elf is corrupted/truncated, avoid calling elf_strptr. */
+	/* ELF is corrupted/truncated, avoid calling elf_strptr. */
 	if (!elf_rawdata(elf_getscn(elf, obj->efile.shstrndx), NULL)) {
 		pr_warn("elf: failed to get section names strings from %s: %s\n",
 			obj->path, elf_errmsg(-1));
@@ -1498,16 +1501,36 @@ static struct bpf_map *bpf_object__add_map(struct bpf_object *obj)
 	return map;
 }
 
-static size_t bpf_map_mmap_sz(const struct bpf_map *map)
+static size_t bpf_map_mmap_sz(unsigned int value_sz, unsigned int max_entries)
 {
-	long page_sz = sysconf(_SC_PAGE_SIZE);
+	const long page_sz = sysconf(_SC_PAGE_SIZE);
 	size_t map_sz;
 
-	map_sz = (size_t)roundup(map->def.value_size, 8) * map->def.max_entries;
+	map_sz = (size_t)roundup(value_sz, 8) * max_entries;
 	map_sz = roundup(map_sz, page_sz);
 	return map_sz;
 }
 
+static int bpf_map_mmap_resize(struct bpf_map *map, size_t old_sz, size_t new_sz)
+{
+	void *mmaped;
+
+	if (!map->mmaped)
+		return -EINVAL;
+
+	if (old_sz == new_sz)
+		return 0;
+
+	mmaped = mmap(NULL, new_sz, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+	if (mmaped == MAP_FAILED)
+		return -errno;
+
+	memcpy(mmaped, map->mmaped, min(old_sz, new_sz));
+	munmap(map->mmaped, old_sz);
+	map->mmaped = mmaped;
+	return 0;
+}
+
 static char *internal_map_name(struct bpf_object *obj, const char *real_name)
 {
 	char map_name[BPF_OBJ_NAME_LEN], *p;
@@ -1606,6 +1629,7 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
 {
 	struct bpf_map_def *def;
 	struct bpf_map *map;
+	size_t mmap_sz;
 	int err;
 
 	map = bpf_object__add_map(obj);
@@ -1640,7 +1664,8 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
 	pr_debug("map '%s' (global data): at sec_idx %d, offset %zu, flags %x.\n",
 		 map->name, map->sec_idx, map->sec_offset, def->map_flags);
 
-	map->mmaped = mmap(NULL, bpf_map_mmap_sz(map), PROT_READ | PROT_WRITE,
+	mmap_sz = bpf_map_mmap_sz(map->def.value_size, map->def.max_entries);
+	map->mmaped = mmap(NULL, mmap_sz, PROT_READ | PROT_WRITE,
 			   MAP_SHARED | MAP_ANONYMOUS, -1, 0);
 	if (map->mmaped == MAP_FAILED) {
 		err = -errno;
@@ -4327,7 +4352,7 @@ static int bpf_get_map_info_from_fdinfo(int fd, struct bpf_map_info *info)
 	snprintf(file, sizeof(file), "/proc/%d/fdinfo/%d", getpid(), fd);
 	memset(info, 0, sizeof(*info));
 
-	fp = fopen(file, "r");
+	fp = fopen(file, "re");
 	if (!fp) {
 		err = -errno;
 		pr_warn("failed to open %s: %d. No procfs support?\n", file,
@@ -4390,18 +4415,17 @@ int bpf_map__reuse_fd(struct bpf_map *map, int fd)
 	if (!new_name)
 		return libbpf_err(-errno);
 
-	new_fd = open("/", O_RDONLY | O_CLOEXEC);
+	/*
+	 * Like dup(), but make sure new FD is >= 3 and has O_CLOEXEC set.
+	 * This is similar to what we do in ensure_good_fd(), but without
+	 * closing original FD.
+	 */
+	new_fd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
 	if (new_fd < 0) {
 		err = -errno;
 		goto err_free_new_name;
 	}
 
-	new_fd = dup3(fd, new_fd, O_CLOEXEC);
-	if (new_fd < 0) {
-		err = -errno;
-		goto err_close_new_fd;
-	}
-
 	err = zclose(map->fd);
 	if (err) {
 		err = -errno;
@@ -5447,6 +5471,10 @@ static int load_module_btfs(struct bpf_object *obj)
 		err = bpf_btf_get_next_id(id, &id);
 		if (err && errno == ENOENT)
 			return 0;
+		if (err && errno == EPERM) {
+			pr_debug("skipping module BTFs loading, missing privileges\n");
+			return 0;
+		}
 		if (err) {
 			err = -errno;
 			pr_warn("failed to iterate BTF objects: %d\n", err);
@@ -6133,7 +6161,11 @@ static int append_subprog_relos(struct bpf_program *main_prog, struct bpf_progra
 	if (main_prog == subprog)
 		return 0;
 	relos = libbpf_reallocarray(main_prog->reloc_desc, new_cnt, sizeof(*relos));
-	if (!relos)
+	/* if new count is zero, reallocarray can return a valid NULL result;
+	 * in this case the previous pointer will be freed, so we *have to*
+	 * reassign old pointer to the new value (even if it's NULL)
+	 */
+	if (!relos && new_cnt)
 		return -ENOMEM;
 	if (subprog->nr_reloc)
 		memcpy(relos + main_prog->nr_reloc, subprog->reloc_desc,
@@ -7431,7 +7463,7 @@ int libbpf_kallsyms_parse(kallsyms_cb_t cb, void *ctx)
 	int ret, err = 0;
 	FILE *f;
 
-	f = fopen("/proc/kallsyms", "r");
+	f = fopen("/proc/kallsyms", "re");
 	if (!f) {
 		err = -errno;
 		pr_warn("failed to open /proc/kallsyms: %d\n", err);
@@ -8292,7 +8324,10 @@ static void bpf_map__destroy(struct bpf_map *map)
 	map->init_slots_sz = 0;
 
 	if (map->mmaped) {
-		munmap(map->mmaped, bpf_map_mmap_sz(map));
+		size_t mmap_sz;
+
+		mmap_sz = bpf_map_mmap_sz(map->def.value_size, map->def.max_entries);
+		munmap(map->mmaped, mmap_sz);
 		map->mmaped = NULL;
 	}
 
@@ -8501,7 +8536,8 @@ int bpf_program__set_insns(struct bpf_program *prog,
 		return -EBUSY;
 
 	insns = libbpf_reallocarray(prog->insns, new_insn_cnt, sizeof(*insns));
-	if (!insns) {
+	/* NULL is a valid return from reallocarray if the new count is zero */
+	if (!insns && new_insn_cnt) {
 		pr_warn("prog '%s': failed to realloc prog code\n", prog->name);
 		return -ENOMEM;
 	}
@@ -8531,13 +8567,31 @@ enum bpf_prog_type bpf_program__type(const struct bpf_program *prog)
 	return prog->type;
 }
 
+static size_t custom_sec_def_cnt;
+static struct bpf_sec_def *custom_sec_defs;
+static struct bpf_sec_def custom_fallback_def;
+static bool has_custom_fallback_def;
+static int last_custom_sec_def_handler_id;
+
 int bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
 {
 	if (prog->obj->loaded)
 		return libbpf_err(-EBUSY);
 
+	/* if type is not changed, do nothing */
+	if (prog->type == type)
+		return 0;
+
 	prog->type = type;
-	prog->sec_def = NULL;
+
+	/* If a program type was changed, we need to reset associated SEC()
+	 * handler, as it will be invalid now. The only exception is a generic
+	 * fallback handler, which by definition is program type-agnostic and
+	 * is a catch-all custom handler, optionally set by the application,
+	 * so should be able to handle any type of BPF program.
+	 */
+	if (prog->sec_def != &custom_fallback_def)
+		prog->sec_def = NULL;
 	return 0;
 }
 
@@ -8710,15 +8764,9 @@ static const struct bpf_sec_def section_defs[] = {
 	SEC_DEF("struct_ops+",		STRUCT_OPS, 0, SEC_NONE),
 	SEC_DEF("struct_ops.s+",	STRUCT_OPS, 0, SEC_SLEEPABLE),
 	SEC_DEF("sk_lookup",		SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE),
+	SEC_DEF("netfilter",		NETFILTER, BPF_NETFILTER, SEC_NONE),
 };
 
-static size_t custom_sec_def_cnt;
-static struct bpf_sec_def *custom_sec_defs;
-static struct bpf_sec_def custom_fallback_def;
-static bool has_custom_fallback_def;
-
-static int last_custom_sec_def_handler_id;
-
 int libbpf_register_prog_handler(const char *sec,
 				 enum bpf_prog_type prog_type,
 				 enum bpf_attach_type exp_attach_type,
@@ -8798,7 +8846,11 @@ int libbpf_unregister_prog_handler(int handler_id)
 
 	/* try to shrink the array, but it's ok if we couldn't */
 	sec_defs = libbpf_reallocarray(custom_sec_defs, custom_sec_def_cnt, sizeof(*sec_defs));
-	if (sec_defs)
+	/* if new count is zero, reallocarray can return a valid NULL result;
+	 * in this case the previous pointer will be freed, so we *have to*
+	 * reassign old pointer to the new value (even if it's NULL)
+	 */
+	if (sec_defs || custom_sec_def_cnt == 0)
 		custom_sec_defs = sec_defs;
 
 	return 0;
@@ -9409,10 +9461,103 @@ __u32 bpf_map__value_size(const struct bpf_map *map)
 	return map->def.value_size;
 }
 
+static int map_btf_datasec_resize(struct bpf_map *map, __u32 size)
+{
+	struct btf *btf;
+	struct btf_type *datasec_type, *var_type;
+	struct btf_var_secinfo *var;
+	const struct btf_type *array_type;
+	const struct btf_array *array;
+	int vlen, element_sz, new_array_id;
+	__u32 nr_elements;
+
+	/* check btf existence */
+	btf = bpf_object__btf(map->obj);
+	if (!btf)
+		return -ENOENT;
+
+	/* verify map is datasec */
+	datasec_type = btf_type_by_id(btf, bpf_map__btf_value_type_id(map));
+	if (!btf_is_datasec(datasec_type)) {
+		pr_warn("map '%s': cannot be resized, map value type is not a datasec\n",
+			bpf_map__name(map));
+		return -EINVAL;
+	}
+
+	/* verify datasec has at least one var */
+	vlen = btf_vlen(datasec_type);
+	if (vlen == 0) {
+		pr_warn("map '%s': cannot be resized, map value datasec is empty\n",
+			bpf_map__name(map));
+		return -EINVAL;
+	}
+
+	/* verify last var in the datasec is an array */
+	var = &btf_var_secinfos(datasec_type)[vlen - 1];
+	var_type = btf_type_by_id(btf, var->type);
+	array_type = skip_mods_and_typedefs(btf, var_type->type, NULL);
+	if (!btf_is_array(array_type)) {
+		pr_warn("map '%s': cannot be resized, last var must be an array\n",
+			bpf_map__name(map));
+		return -EINVAL;
+	}
+
+	/* verify request size aligns with array */
+	array = btf_array(array_type);
+	element_sz = btf__resolve_size(btf, array->type);
+	if (element_sz <= 0 || (size - var->offset) % element_sz != 0) {
+		pr_warn("map '%s': cannot be resized, element size (%d) doesn't align with new total size (%u)\n",
+			bpf_map__name(map), element_sz, size);
+		return -EINVAL;
+	}
+
+	/* create a new array based on the existing array, but with new length */
+	nr_elements = (size - var->offset) / element_sz;
+	new_array_id = btf__add_array(btf, array->index_type, array->type, nr_elements);
+	if (new_array_id < 0)
+		return new_array_id;
+
+	/* adding a new btf type invalidates existing pointers to btf objects,
+	 * so refresh pointers before proceeding
+	 */
+	datasec_type = btf_type_by_id(btf, map->btf_value_type_id);
+	var = &btf_var_secinfos(datasec_type)[vlen - 1];
+	var_type = btf_type_by_id(btf, var->type);
+
+	/* finally update btf info */
+	datasec_type->size = size;
+	var->size = size - var->offset;
+	var_type->type = new_array_id;
+
+	return 0;
+}
+
 int bpf_map__set_value_size(struct bpf_map *map, __u32 size)
 {
 	if (map->fd >= 0)
 		return libbpf_err(-EBUSY);
+
+	if (map->mmaped) {
+		int err;
+		size_t mmap_old_sz, mmap_new_sz;
+
+		mmap_old_sz = bpf_map_mmap_sz(map->def.value_size, map->def.max_entries);
+		mmap_new_sz = bpf_map_mmap_sz(size, map->def.max_entries);
+		err = bpf_map_mmap_resize(map, mmap_old_sz, mmap_new_sz);
+		if (err) {
+			pr_warn("map '%s': failed to resize memory-mapped region: %d\n",
+				bpf_map__name(map), err);
+			return err;
+		}
+		err = map_btf_datasec_resize(map, size);
+		if (err && err != -ENOENT) {
+			pr_warn("map '%s': failed to adjust resized BTF, clearing BTF key/value info: %d\n",
+				bpf_map__name(map), err);
+			map->btf_value_type_id = 0;
+			map->btf_key_type_id = 0;
+		}
+	}
+
 	map->def.value_size = size;
 	return 0;
 }
@@ -9438,7 +9583,7 @@ int bpf_map__set_initial_value(struct bpf_map *map,
 	return 0;
 }
 
-const void *bpf_map__initial_value(struct bpf_map *map, size_t *psize)
+void *bpf_map__initial_value(struct bpf_map *map, size_t *psize)
 {
 	if (!map->mmaped)
 		return NULL;
@@ -9954,7 +10099,7 @@ static int parse_uint_from_file(const char *file, const char *fmt)
 	int err, ret;
 	FILE *f;
 
-	f = fopen(file, "r");
+	f = fopen(file, "re");
 	if (!f) {
 		err = -errno;
 		pr_debug("failed to open '%s': %s\n", file,
@@ -10103,6 +10248,18 @@ static const char *tracefs_uprobe_events(void)
 	return use_debugfs() ? DEBUGFS"/uprobe_events" : TRACEFS"/uprobe_events";
 }
 
+static const char *tracefs_available_filter_functions(void)
+{
+	return use_debugfs() ? DEBUGFS"/available_filter_functions"
+			     : TRACEFS"/available_filter_functions";
+}
+
+static const char *tracefs_available_filter_functions_addrs(void)
+{
+	return use_debugfs() ? DEBUGFS"/available_filter_functions_addrs"
+			     : TRACEFS"/available_filter_functions_addrs";
+}
+
 static void gen_kprobe_legacy_event_name(char *buf, size_t buf_sz,
 					 const char *kfunc_name, size_t offset)
 {
@@ -10418,25 +10575,158 @@ struct kprobe_multi_resolve {
 	size_t cnt;
 };
 
-static int
+struct avail_kallsyms_data {
-resolve_kprobe_multi_cb(unsigned long long sym_addr, char sym_type,
+	char **syms;
-			const char *sym_name, void *ctx)
+	size_t cnt;
+	struct kprobe_multi_resolve *res;
+};
+
+static int avail_func_cmp(const void *a, const void *b)
 {
-	struct kprobe_multi_resolve *res = ctx;
+	return strcmp(*(const char **)a, *(const char **)b);
+}
+
+static int avail_kallsyms_cb(unsigned long long sym_addr, char sym_type,
+			     const char *sym_name, void *ctx)
+{
+	struct avail_kallsyms_data *data = ctx;
+	struct kprobe_multi_resolve *res = data->res;
 	int err;
 
-	if (!glob_match(sym_name, res->pattern))
+	if (!bsearch(&sym_name, data->syms, data->cnt, sizeof(*data->syms), avail_func_cmp))
 		return 0;
 
-	err = libbpf_ensure_mem((void **) &res->addrs, &res->cap, sizeof(unsigned long),
+	err = libbpf_ensure_mem((void **)&res->addrs, &res->cap, sizeof(*res->addrs), res->cnt + 1);
-				res->cnt + 1);
 	if (err)
 		return err;
 
-	res->addrs[res->cnt++] = (unsigned long) sym_addr;
+	res->addrs[res->cnt++] = (unsigned long)sym_addr;
 	return 0;
 }
 
+static int libbpf_available_kallsyms_parse(struct kprobe_multi_resolve *res)
+{
+	const char *available_functions_file = tracefs_available_filter_functions();
+	struct avail_kallsyms_data data;
+	char sym_name[500];
+	FILE *f;
+	int err = 0, ret, i;
+	char **syms = NULL;
+	size_t cap = 0, cnt = 0;
+
+	f = fopen(available_functions_file, "re");
+	if (!f) {
+		err = -errno;
+		pr_warn("failed to open %s: %d\n", available_functions_file, err);
+		return err;
+	}
+
+	while (true) {
+		char *name;
+
+		ret = fscanf(f, "%499s%*[^\n]\n", sym_name);
+		if (ret == EOF && feof(f))
+			break;
+
+		if (ret != 1) {
+			pr_warn("failed to parse available_filter_functions entry: %d\n", ret);
+			err = -EINVAL;
+			goto cleanup;
+		}
+
+		if (!glob_match(sym_name, res->pattern))
+			continue;
+
+		err = libbpf_ensure_mem((void **)&syms, &cap, sizeof(*syms), cnt + 1);
+		if (err)
+			goto cleanup;
+
+		name = strdup(sym_name);
+		if (!name) {
+			err = -errno;
+			goto cleanup;
+		}
+
+		syms[cnt++] = name;
+	}
+
+	/* no entries found, bail out */
+	if (cnt == 0) {
+		err = -ENOENT;
+		goto cleanup;
+	}
+
+	/* sort available functions */
+	qsort(syms, cnt, sizeof(*syms), avail_func_cmp);
+
+	data.syms = syms;
+	data.res = res;
+	data.cnt = cnt;
+	libbpf_kallsyms_parse(avail_kallsyms_cb, &data);
+
+	if (res->cnt == 0)
+		err = -ENOENT;
+
+cleanup:
+	for (i = 0; i < cnt; i++)
+		free((char *)syms[i]);
+	free(syms);
+
+	fclose(f);
+	return err;
+}
+
+static bool has_available_filter_functions_addrs(void)
+{
+	return access(tracefs_available_filter_functions_addrs(), R_OK) != -1;
+}
+
+static int libbpf_available_kprobes_parse(struct kprobe_multi_resolve *res)
+{
+	const char *available_path = tracefs_available_filter_functions_addrs();
+	char sym_name[500];
+	FILE *f;
+	int ret, err = 0;
+	unsigned long long sym_addr;
+
+	f = fopen(available_path, "re");
+	if (!f) {
+		err = -errno;
+		pr_warn("failed to open %s: %d\n", available_path, err);
+		return err;
+	}
+
+	while (true) {
+		ret = fscanf(f, "%llx %499s%*[^\n]\n", &sym_addr, sym_name);
+		if (ret == EOF && feof(f))
+			break;
+
+		if (ret != 2) {
+			pr_warn("failed to parse available_filter_functions_addrs entry: %d\n",
+				ret);
+			err = -EINVAL;
+			goto cleanup;
+		}
+
+		if (!glob_match(sym_name, res->pattern))
+			continue;
+
+		err = libbpf_ensure_mem((void **)&res->addrs, &res->cap,
+					sizeof(*res->addrs), res->cnt + 1);
+		if (err)
+			goto cleanup;
+
+		res->addrs[res->cnt++] = (unsigned long)sym_addr;
+	}
+
+	if (res->cnt == 0)
+		err = -ENOENT;
+
+cleanup:
+	fclose(f);
+	return err;
+}
+
 struct bpf_link *
 bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
 				      const char *pattern,
@@ -10473,13 +10763,12 @@ bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
 		return libbpf_err_ptr(-EINVAL);
 
 	if (pattern) {
-		err = libbpf_kallsyms_parse(resolve_kprobe_multi_cb, &res);
+		if (has_available_filter_functions_addrs())
+			err = libbpf_available_kprobes_parse(&res);
+		else
+			err = libbpf_available_kallsyms_parse(&res);
 		if (err)
 			goto error;
-		if (!res.cnt) {
-			err = -ENOENT;
-			goto error;
-		}
 		addrs = res.addrs;
 		cnt = res.cnt;
 	}
@@ -11690,6 +11979,48 @@ static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_l
 	return libbpf_get_error(*link);
 }
 
+struct bpf_link *bpf_program__attach_netfilter(const struct bpf_program *prog,
+					       const struct bpf_netfilter_opts *opts)
+{
+	LIBBPF_OPTS(bpf_link_create_opts, lopts);
+	struct bpf_link *link;
+	int prog_fd, link_fd;
+
+	if (!OPTS_VALID(opts, bpf_netfilter_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	prog_fd = bpf_program__fd(prog);
+	if (prog_fd < 0) {
+		pr_warn("prog '%s': can't attach before loaded\n", prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	link = calloc(1, sizeof(*link));
+	if (!link)
+		return libbpf_err_ptr(-ENOMEM);
+
+	link->detach = &bpf_link__detach_fd;
+
+	lopts.netfilter.pf = OPTS_GET(opts, pf, 0);
+	lopts.netfilter.hooknum = OPTS_GET(opts, hooknum, 0);
+	lopts.netfilter.priority = OPTS_GET(opts, priority, 0);
+	lopts.netfilter.flags = OPTS_GET(opts, flags, 0);
+
+	link_fd = bpf_link_create(prog_fd, 0, BPF_NETFILTER, &lopts);
+	if (link_fd < 0) {
+		char errmsg[STRERR_BUFSIZE];
+
+		link_fd = -errno;
+		free(link);
+		pr_warn("prog '%s': failed to attach to netfilter: %s\n",
+			prog->name, libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg)));
+		return libbpf_err_ptr(link_fd);
+	}
+	link->fd = link_fd;
+
+	return link;
+}
+
 struct bpf_link *bpf_program__attach(const struct bpf_program *prog)
 {
 	struct bpf_link *link = NULL;
@@ -12690,7 +13021,7 @@ int bpf_object__load_skeleton(struct bpf_object_skeleton *s)
 
 	for (i = 0; i < s->map_cnt; i++) {
 		struct bpf_map *map = *s->maps[i].map;
-		size_t mmap_sz = bpf_map_mmap_sz(map);
+		size_t mmap_sz = bpf_map_mmap_sz(map->def.value_size, map->def.max_entries);
 		int prot, map_fd = bpf_map__fd(map);
 		void **mmaped = s->maps[i].mmaped;
 
@@ -12717,8 +13048,7 @@ int bpf_object__load_skeleton(struct bpf_object_skeleton *s)
 		 * as per normal clean up procedure, so we don't need to worry
 		 * about it from skeleton's clean up perspective.
 		 */
-		*mmaped = mmap(map->mmaped, mmap_sz, prot,
+		*mmaped = mmap(map->mmaped, mmap_sz, prot, MAP_SHARED | MAP_FIXED, map_fd, 0);
-				MAP_SHARED | MAP_FIXED, map_fd, 0);
 		if (*mmaped == MAP_FAILED) {
 			err = -errno;
 			*mmaped = NULL;

src/libbpf.h

@@ -718,6 +718,21 @@ LIBBPF_API struct bpf_link *
 bpf_program__attach_freplace(const struct bpf_program *prog,
 			     int target_fd, const char *attach_func_name);
 
+struct bpf_netfilter_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+
+	__u32 pf;
+	__u32 hooknum;
+	__s32 priority;
+	__u32 flags;
+};
+#define bpf_netfilter_opts__last_field flags
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_netfilter(const struct bpf_program *prog,
+			      const struct bpf_netfilter_opts *opts);
+
 struct bpf_map;
 
 LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map);
@@ -869,8 +884,22 @@ LIBBPF_API int bpf_map__set_numa_node(struct bpf_map *map, __u32 numa_node);
 /* get/set map key size */
 LIBBPF_API __u32 bpf_map__key_size(const struct bpf_map *map);
 LIBBPF_API int bpf_map__set_key_size(struct bpf_map *map, __u32 size);
-/* get/set map value size */
+/* get map value size */
 LIBBPF_API __u32 bpf_map__value_size(const struct bpf_map *map);
+/**
+ * @brief **bpf_map__set_value_size()** sets map value size.
+ * @param map the BPF map instance
+ * @return 0, on success; negative error, otherwise
+ *
+ * There is a special case for maps with associated memory-mapped regions, like
+ * the global data section maps (bss, data, rodata). When this function is used
+ * on such a map, the mapped region is resized. Afterward, an attempt is made to
+ * adjust the corresponding BTF info. This attempt is best-effort and can only
+ * succeed if the last variable of the data section map is an array. The array
+ * BTF type is replaced by a new BTF array type with a different length.
+ * Any previously existing pointers returned from bpf_map__initial_value() or
+ * corresponding data section skeleton pointer must be reinitialized.
+ */
 LIBBPF_API int bpf_map__set_value_size(struct bpf_map *map, __u32 size);
 /* get map key/value BTF type IDs */
 LIBBPF_API __u32 bpf_map__btf_key_type_id(const struct bpf_map *map);
@@ -884,7 +913,7 @@ LIBBPF_API int bpf_map__set_map_extra(struct bpf_map *map, __u64 map_extra);
 
 LIBBPF_API int bpf_map__set_initial_value(struct bpf_map *map,
 					  const void *data, size_t size);
-LIBBPF_API const void *bpf_map__initial_value(struct bpf_map *map, size_t *psize);
+LIBBPF_API void *bpf_map__initial_value(struct bpf_map *map, size_t *psize);
 
 /**
  * @brief **bpf_map__is_internal()** tells the caller whether or not the

src/libbpf.map

@@ -391,3 +391,9 @@ LIBBPF_1.2.0 {
 		bpf_map_get_info_by_fd;
 		bpf_prog_get_info_by_fd;
 } LIBBPF_1.1.0;
+
+LIBBPF_1.3.0 {
+	global:
+		bpf_obj_pin_opts;
+		bpf_program__attach_netfilter;
+} LIBBPF_1.2.0;

src/libbpf_probes.c

@@ -38,7 +38,7 @@ static __u32 get_ubuntu_kernel_version(void)
 	if (faccessat(AT_FDCWD, ubuntu_kver_file, R_OK, AT_EACCESS) != 0)
 		return 0;
 
-	f = fopen(ubuntu_kver_file, "r");
+	f = fopen(ubuntu_kver_file, "re");
 	if (!f)
 		return 0;
 
@@ -181,6 +181,9 @@ static int probe_prog_load(enum bpf_prog_type prog_type,
 	case BPF_PROG_TYPE_FLOW_DISSECTOR:
 	case BPF_PROG_TYPE_CGROUP_SYSCTL:
 		break;
+	case BPF_PROG_TYPE_NETFILTER:
+		opts.expected_attach_type = BPF_NETFILTER;
+		break;
 	default:
 		return -EOPNOTSUPP;
 	}

src/libbpf_version.h

@@ -4,6 +4,6 @@
 #define __LIBBPF_VERSION_H
 
 #define LIBBPF_MAJOR_VERSION 1
-#define LIBBPF_MINOR_VERSION 2
+#define LIBBPF_MINOR_VERSION 3
 
 #endif /* __LIBBPF_VERSION_H */

src/usdt.c

@@ -466,7 +466,7 @@ static int parse_vma_segs(int pid, const char *lib_path, struct elf_seg **segs,
 
 proceed:
 	sprintf(line, "/proc/%d/maps", pid);
-	f = fopen(line, "r");
+	f = fopen(line, "re");
 	if (!f) {
 		err = -errno;
 		pr_warn("usdt: failed to open '%s' to get base addr of '%s': %d\n",
@@ -771,7 +771,7 @@ static int collect_usdt_targets(struct usdt_manager *man, Elf *elf, const char *
 		target->rel_ip = usdt_rel_ip;
 		target->sema_off = usdt_sema_off;
 
-		/* notes.args references strings from Elf itself, so they can
+		/* notes.args references strings from ELF itself, so they can
 		 * be referenced safely until elf_end() call
 		 */
 		target->spec_str = note.args;
@@ -852,8 +852,11 @@ static int bpf_link_usdt_detach(struct bpf_link *link)
 		 * system is so exhausted on memory, it's the least of user's
 		 * concerns, probably.
 		 * So just do our best here to return those IDs to usdt_manager.
+		 * Another edge case when we can legitimately get NULL is when
+		 * new_cnt is zero, which can happen in some edge cases, so we
+		 * need to be careful about that.
 		 */
-		if (new_free_ids) {
+		if (new_free_ids || new_cnt == 0) {
 			memcpy(new_free_ids + man->free_spec_cnt, usdt_link->spec_ids,
 			       usdt_link->spec_cnt * sizeof(*usdt_link->spec_ids));
 			man->free_spec_ids = new_free_ids;
@@ -954,8 +957,7 @@ struct bpf_link *usdt_manager_attach_usdt(struct usdt_manager *man, const struct
 	spec_map_fd = bpf_map__fd(man->specs_map);
 	ip_map_fd = bpf_map__fd(man->ip_to_spec_id_map);
 
-	/* TODO: perform path resolution similar to uprobe's */
+	fd = open(path, O_RDONLY | O_CLOEXEC);
-	fd = open(path, O_RDONLY);
 	if (fd < 0) {
 		err = -errno;
 		pr_warn("usdt: failed to open ELF binary '%s': %d\n", path, err);