Merge branch 'Typeless/weak ksym for gen_loader + misc fixups'

Kumar Kartikeya says:

====================

Patches (1,2,3,6) add typeless and weak ksym support to gen_loader. It is follow
up for the recent kfunc from modules series.

The later patches (7,8) are misc fixes for selftests, and patch 4 for libbpf
where we try to be careful to not end up with fds == 0, as libbpf assumes in
various places that they are greater than 0. Patch 5 fixes up missing O_CLOEXEC
in libbpf.

Changelog:
----------
v4 -> v5
v4: https://lore.kernel.org/bpf/20211020191526.2306852-1-memxor@gmail.com

 * Address feedback from Andrii
   * Drop use of ensure_good_fd in unneeded call sites
   * Add sys_bpf_fd
   * Add _lskel suffix to all light skeletons and change all current selftests
   * Drop early break in close loop for sk_lookup
   * Fix other nits

v3 -> v4
v3: https://lore.kernel.org/bpf/20211014205644.1837280-1-memxor@gmail.com

 * Remove gpl_only = true from bpf_kallsyms_lookup_name (Alexei)
 * Add bpf_dump_raw_ok check to ensure kptr_restrict isn't bypassed (Alexei)

v2 -> v3
v2: https://lore.kernel.org/bpf/20211013073348.1611155-1-memxor@gmail.com

 * Address feedback from Song
   * Move ksym logging to separate helper to avoid code duplication
   * Move src_reg mask stuff to separate helper
   * Fix various other nits, add acks
     * __builtin_expect is used instead of likely to as skel_internal.h is
       included in isolation.

v1 -> v2
v1: https://lore.kernel.org/bpf/20211006002853.308945-1-memxor@gmail.com

 * Remove redundant OOM checks in emit_bpf_kallsyms_lookup_name
 * Use designated initializer for sk_lookup fd array (Jakub)
 * Do fd check for all fd returning low level APIs (Andrii, Alexei)
 * Make Fixes: tag quote commit message, use selftests/bpf prefix (Song, Andrii)
 * Split typeless and weak ksym support into separate patches, expand commit
   message (Song)
 * Fix duplication in selftests stemming from use of LSKELS_EXTRA (Song)
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

include/linux/bpf.h

@@ -2110,6 +2110,7 @@ extern const struct bpf_func_proto bpf_for_each_map_elem_proto;
 extern const struct bpf_func_proto bpf_btf_find_by_name_kind_proto;
 extern const struct bpf_func_proto bpf_sk_setsockopt_proto;
 extern const struct bpf_func_proto bpf_sk_getsockopt_proto;
+extern const struct bpf_func_proto bpf_kallsyms_lookup_name_proto;
 
 const struct bpf_func_proto *tracing_prog_func_proto(
   enum bpf_func_id func_id, const struct bpf_prog *prog);

include/uapi/linux/bpf.h

@@ -4923,6 +4923,21 @@ union bpf_attr {
  *		Dynamically cast a *sk* pointer to a *unix_sock* pointer.
  *	Return
  *		*sk* if casting is valid, or **NULL** otherwise.
+ *
+ * long bpf_kallsyms_lookup_name(const char *name, int name_sz, int flags, u64 *res)
+ *	Description
+ *		Get the address of a kernel symbol, returned in *res*. *res* is
+ *		set to 0 if the symbol is not found.
+ *	Return
+ *		On success, zero. On error, a negative value.
+ *
+ *		**-EINVAL** if *flags* is not zero.
+ *
+ *		**-EINVAL** if string *name* is not the same size as *name_sz*.
+ *
+ *		**-ENOENT** if symbol is not found.
+ *
+ *		**-EPERM** if caller does not have permission to obtain kernel address.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -5104,6 +5119,7 @@ union bpf_attr {
 	FN(get_branch_snapshot),	\
 	FN(trace_vprintk),		\
 	FN(skc_to_unix_sock),		\
+	FN(kallsyms_lookup_name),	\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper

kernel/bpf/syscall.c

@@ -4781,6 +4781,31 @@ static const struct bpf_func_proto bpf_sys_close_proto = {
 	.arg1_type	= ARG_ANYTHING,
 };
 
+BPF_CALL_4(bpf_kallsyms_lookup_name, const char *, name, int, name_sz, int, flags, u64 *, res)
+{
+	if (flags)
+		return -EINVAL;
+
+	if (name_sz <= 1 || name[name_sz - 1])
+		return -EINVAL;
+
+	if (!bpf_dump_raw_ok(current_cred()))
+		return -EPERM;
+
+	*res = kallsyms_lookup_name(name);
+	return *res ? 0 : -ENOENT;
+}
+
+const struct bpf_func_proto bpf_kallsyms_lookup_name_proto = {
+	.func		= bpf_kallsyms_lookup_name,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_MEM,
+	.arg2_type	= ARG_CONST_SIZE,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_PTR_TO_LONG,
+};
+
 static const struct bpf_func_proto *
 syscall_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 {
@@ -4791,6 +4816,8 @@ syscall_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_btf_find_by_name_kind_proto;
 	case BPF_FUNC_sys_close:
 		return &bpf_sys_close_proto;
+	case BPF_FUNC_kallsyms_lookup_name:
+		return &bpf_kallsyms_lookup_name_proto;
 	default:
 		return tracing_prog_func_proto(func_id, prog);
 	}

tools/include/uapi/linux/bpf.h

@@ -4923,6 +4923,21 @@ union bpf_attr {
  *		Dynamically cast a *sk* pointer to a *unix_sock* pointer.
  *	Return
  *		*sk* if casting is valid, or **NULL** otherwise.
+ *
+ * long bpf_kallsyms_lookup_name(const char *name, int name_sz, int flags, u64 *res)
+ *	Description
+ *		Get the address of a kernel symbol, returned in *res*. *res* is
+ *		set to 0 if the symbol is not found.
+ *	Return
+ *		On success, zero. On error, a negative value.
+ *
+ *		**-EINVAL** if *flags* is not zero.
+ *
+ *		**-EINVAL** if string *name* is not the same size as *name_sz*.
+ *
+ *		**-ENOENT** if symbol is not found.
+ *
+ *		**-EPERM** if caller does not have permission to obtain kernel address.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -5104,6 +5119,7 @@ union bpf_attr {
 	FN(get_branch_snapshot),	\
 	FN(trace_vprintk),		\
 	FN(skc_to_unix_sock),		\
+	FN(kallsyms_lookup_name),	\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper

tools/lib/bpf/bpf.c

@@ -65,13 +65,22 @@ static inline int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
 	return syscall(__NR_bpf, cmd, attr, size);
 }
 
+static inline int sys_bpf_fd(enum bpf_cmd cmd, union bpf_attr *attr,
+			     unsigned int size)
+{
+	int fd;
+
+	fd = sys_bpf(cmd, attr, size);
+	return ensure_good_fd(fd);
+}
+
 static inline int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size)
 {
 	int retries = 5;
 	int fd;
 
 	do {
-		fd = sys_bpf(BPF_PROG_LOAD, attr, size);
+		fd = sys_bpf_fd(BPF_PROG_LOAD, attr, size);
 	} while (fd < 0 && errno == EAGAIN && retries-- > 0);
 
 	return fd;
@@ -104,7 +113,7 @@ int libbpf__bpf_create_map_xattr(const struct bpf_create_map_params *create_attr
 		attr.inner_map_fd = create_attr->inner_map_fd;
 	attr.map_extra = create_attr->map_extra;
 
-	fd = sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
+	fd = sys_bpf_fd(BPF_MAP_CREATE, &attr, sizeof(attr));
 	return libbpf_err_errno(fd);
 }
 
@@ -206,7 +215,7 @@ int bpf_create_map_in_map_node(enum bpf_map_type map_type, const char *name,
 		attr.numa_node = node;
 	}
 
-	fd = sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
+	fd = sys_bpf_fd(BPF_MAP_CREATE, &attr, sizeof(attr));
 	return libbpf_err_errno(fd);
 }
 
@@ -634,7 +643,7 @@ int bpf_obj_get(const char *pathname)
 	memset(&attr, 0, sizeof(attr));
 	attr.pathname = ptr_to_u64((void *)pathname);
 
-	fd = sys_bpf(BPF_OBJ_GET, &attr, sizeof(attr));
+	fd = sys_bpf_fd(BPF_OBJ_GET, &attr, sizeof(attr));
 	return libbpf_err_errno(fd);
 }
 
@@ -745,7 +754,7 @@ int bpf_link_create(int prog_fd, int target_fd,
 		break;
 	}
 proceed:
-	fd = sys_bpf(BPF_LINK_CREATE, &attr, sizeof(attr));
+	fd = sys_bpf_fd(BPF_LINK_CREATE, &attr, sizeof(attr));
 	return libbpf_err_errno(fd);
 }
 
@@ -788,7 +797,7 @@ int bpf_iter_create(int link_fd)
 	memset(&attr, 0, sizeof(attr));
 	attr.iter_create.link_fd = link_fd;
 
-	fd = sys_bpf(BPF_ITER_CREATE, &attr, sizeof(attr));
+	fd = sys_bpf_fd(BPF_ITER_CREATE, &attr, sizeof(attr));
 	return libbpf_err_errno(fd);
 }
 
@@ -946,7 +955,7 @@ int bpf_prog_get_fd_by_id(__u32 id)
 	memset(&attr, 0, sizeof(attr));
 	attr.prog_id = id;
 
-	fd = sys_bpf(BPF_PROG_GET_FD_BY_ID, &attr, sizeof(attr));
+	fd = sys_bpf_fd(BPF_PROG_GET_FD_BY_ID, &attr, sizeof(attr));
 	return libbpf_err_errno(fd);
 }
 
@@ -958,7 +967,7 @@ int bpf_map_get_fd_by_id(__u32 id)
 	memset(&attr, 0, sizeof(attr));
 	attr.map_id = id;
 
-	fd = sys_bpf(BPF_MAP_GET_FD_BY_ID, &attr, sizeof(attr));
+	fd = sys_bpf_fd(BPF_MAP_GET_FD_BY_ID, &attr, sizeof(attr));
 	return libbpf_err_errno(fd);
 }
 
@@ -970,7 +979,7 @@ int bpf_btf_get_fd_by_id(__u32 id)
 	memset(&attr, 0, sizeof(attr));
 	attr.btf_id = id;
 
-	fd = sys_bpf(BPF_BTF_GET_FD_BY_ID, &attr, sizeof(attr));
+	fd = sys_bpf_fd(BPF_BTF_GET_FD_BY_ID, &attr, sizeof(attr));
 	return libbpf_err_errno(fd);
 }
 
@@ -982,7 +991,7 @@ int bpf_link_get_fd_by_id(__u32 id)
 	memset(&attr, 0, sizeof(attr));
 	attr.link_id = id;
 
-	fd = sys_bpf(BPF_LINK_GET_FD_BY_ID, &attr, sizeof(attr));
+	fd = sys_bpf_fd(BPF_LINK_GET_FD_BY_ID, &attr, sizeof(attr));
 	return libbpf_err_errno(fd);
 }
 
@@ -1013,7 +1022,7 @@ int bpf_raw_tracepoint_open(const char *name, int prog_fd)
 	attr.raw_tracepoint.name = ptr_to_u64(name);
 	attr.raw_tracepoint.prog_fd = prog_fd;
 
-	fd = sys_bpf(BPF_RAW_TRACEPOINT_OPEN, &attr, sizeof(attr));
+	fd = sys_bpf_fd(BPF_RAW_TRACEPOINT_OPEN, &attr, sizeof(attr));
 	return libbpf_err_errno(fd);
 }
 
@@ -1033,7 +1042,7 @@ int bpf_load_btf(const void *btf, __u32 btf_size, char *log_buf, __u32 log_buf_s
 		attr.btf_log_buf = ptr_to_u64(log_buf);
 	}
 
-	fd = sys_bpf(BPF_BTF_LOAD, &attr, sizeof(attr));
+	fd = sys_bpf_fd(BPF_BTF_LOAD, &attr, sizeof(attr));
 
 	if (fd < 0 && !do_log && log_buf && log_buf_size) {
 		do_log = true;
@@ -1075,7 +1084,7 @@ int bpf_enable_stats(enum bpf_stats_type type)
 	memset(&attr, 0, sizeof(attr));
 	attr.enable_stats.type = type;
 
-	fd = sys_bpf(BPF_ENABLE_STATS, &attr, sizeof(attr));
+	fd = sys_bpf_fd(BPF_ENABLE_STATS, &attr, sizeof(attr));
 	return libbpf_err_errno(fd);
 }
 

tools/lib/bpf/bpf_gen_internal.h

@@ -8,13 +8,19 @@ struct ksym_relo_desc {
 	int kind;
 	int insn_idx;
 	bool is_weak;
+	bool is_typeless;
 };
 
 struct ksym_desc {
 	const char *name;
 	int ref;
 	int kind;
+	union {
+		/* used for kfunc */
 		int off;
+		/* used for typeless ksym */
+		bool typeless;
+	};
 	int insn;
 };
 
@@ -49,7 +55,7 @@ void bpf_gen__prog_load(struct bpf_gen *gen, struct bpf_prog_load_params *load_a
 void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *value, __u32 value_size);
 void bpf_gen__map_freeze(struct bpf_gen *gen, int map_idx);
 void bpf_gen__record_attach_target(struct bpf_gen *gen, const char *name, enum bpf_attach_type type);
-void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak, int kind,
-			    int insn_idx);
+void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak,
+			    bool is_typeless, int kind, int insn_idx);
 
 #endif

tools/lib/bpf/btf.c

@@ -897,7 +897,7 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf,
 		return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
 	}
 
-	fd = open(path, O_RDONLY);
+	fd = open(path, O_RDONLY | O_CLOEXEC);
 	if (fd < 0) {
 		err = -errno;
 		pr_warn("failed to open %s: %s\n", path, strerror(errno));

tools/lib/bpf/gen_loader.c

@@ -13,6 +13,7 @@
 #include "hashmap.h"
 #include "bpf_gen_internal.h"
 #include "skel_internal.h"
+#include <asm/byteorder.h>
 
 #define MAX_USED_MAPS	64
 #define MAX_USED_PROGS	32
@@ -560,7 +561,7 @@ static void emit_find_attach_target(struct bpf_gen *gen)
 }
 
 void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak,
-			    int kind, int insn_idx)
+			    bool is_typeless, int kind, int insn_idx)
 {
 	struct ksym_relo_desc *relo;
 
@@ -573,6 +574,7 @@ void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak,
 	relo += gen->relo_cnt;
 	relo->name = name;
 	relo->is_weak = is_weak;
+	relo->is_typeless = is_typeless;
 	relo->kind = kind;
 	relo->insn_idx = insn_idx;
 	gen->relo_cnt++;
@@ -622,6 +624,29 @@ static void emit_bpf_find_by_name_kind(struct bpf_gen *gen, struct ksym_relo_des
 	debug_ret(gen, "find_by_name_kind(%s,%d)", relo->name, relo->kind);
 }
 
+/* Overwrites BPF_REG_{0, 1, 2, 3, 4, 7}
+ * Returns result in BPF_REG_7
+ * Returns u64 symbol addr in BPF_REG_9
+ */
+static void emit_bpf_kallsyms_lookup_name(struct bpf_gen *gen, struct ksym_relo_desc *relo)
+{
+	int name_off, len = strlen(relo->name) + 1, res_off;
+
+	name_off = add_data(gen, relo->name, len);
+	res_off = add_data(gen, NULL, 8); /* res is u64 */
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, name_off));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_2, len));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_3, 0));
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_4, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, res_off));
+	emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_4));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_kallsyms_lookup_name));
+	emit(gen, BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0));
+	emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0));
+	debug_ret(gen, "kallsyms_lookup_name(%s,%d)", relo->name, relo->kind);
+}
+
 /* Expects:
  * BPF_REG_8 - pointer to instruction
  *
@@ -701,10 +726,27 @@ static void emit_relo_kfunc_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo
 		   relo->name, kdesc->ref);
 }
 
+static void emit_ksym_relo_log(struct bpf_gen *gen, struct ksym_relo_desc *relo,
+			       int ref)
+{
+	if (!gen->log_level)
+		return;
+	emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_8,
+			      offsetof(struct bpf_insn, imm)));
+	emit(gen, BPF_LDX_MEM(BPF_H, BPF_REG_9, BPF_REG_8, sizeof(struct bpf_insn) +
+			      offsetof(struct bpf_insn, imm)));
+	debug_regs(gen, BPF_REG_7, BPF_REG_9, " var t=%d w=%d (%s:count=%d): imm[0]: %%d, imm[1]: %%d",
+		   relo->is_typeless, relo->is_weak, relo->name, ref);
+	emit(gen, BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_8, offsetofend(struct bpf_insn, code)));
+	debug_regs(gen, BPF_REG_9, -1, " var t=%d w=%d (%s:count=%d): insn.reg",
+		   relo->is_typeless, relo->is_weak, relo->name, ref);
+}
+
 /* Expects:
  * BPF_REG_8 - pointer to instruction
  */
-static void emit_relo_ksym_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn)
+static void emit_relo_ksym_typeless(struct bpf_gen *gen,
+				    struct ksym_relo_desc *relo, int insn)
 {
 	struct ksym_desc *kdesc;
 
@@ -719,25 +761,81 @@ static void emit_relo_ksym_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo,
 			       kdesc->insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm));
 		goto log;
 	}
+	/* remember insn offset, so we can copy ksym addr later */
+	kdesc->insn = insn;
+	/* skip typeless ksym_desc in fd closing loop in cleanup_relos */
+	kdesc->typeless = true;
+	emit_bpf_kallsyms_lookup_name(gen, relo);
+	emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_7, -ENOENT, 1));
+	emit_check_err(gen);
+	/* store lower half of addr into insn[insn_idx].imm */
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_9, offsetof(struct bpf_insn, imm)));
+	/* store upper half of addr into insn[insn_idx + 1].imm */
+	emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_9, 32));
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_9,
+		      sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm)));
+log:
+	emit_ksym_relo_log(gen, relo, kdesc->ref);
+}
+
+static __u32 src_reg_mask(void)
+{
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	return 0x0f; /* src_reg,dst_reg,... */
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	return 0xf0; /* dst_reg,src_reg,... */
+#else
+#error "Unsupported bit endianness, cannot proceed"
+#endif
+}
+
+/* Expects:
+ * BPF_REG_8 - pointer to instruction
+ */
+static void emit_relo_ksym_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn)
+{
+	struct ksym_desc *kdesc;
+	__u32 reg_mask;
+
+	kdesc = get_ksym_desc(gen, relo);
+	if (!kdesc)
+		return;
+	/* try to copy from existing ldimm64 insn */
+	if (kdesc->ref > 1) {
+		move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4,
+			       kdesc->insn + offsetof(struct bpf_insn, imm));
+		move_blob2blob(gen, insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 4,
+			       kdesc->insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm));
+		emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_9, BPF_REG_8, offsetof(struct bpf_insn, imm)));
+		/* jump over src_reg adjustment if imm is not 0 */
+		emit(gen, BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 0, 3));
+		goto clear_src_reg;
+	}
 	/* remember insn offset, so we can copy BTF ID and FD later */
 	kdesc->insn = insn;
 	emit_bpf_find_by_name_kind(gen, relo);
+	if (!relo->is_weak)
 		emit_check_err(gen);
+	/* set default values as 0 */
+	emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, offsetof(struct bpf_insn, imm), 0));
+	emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 0));
+	/* skip success case stores if ret < 0 */
+	emit(gen, BPF_JMP_IMM(BPF_JSLT, BPF_REG_7, 0, 4));
 	/* store btf_id into insn[insn_idx].imm */
 	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7, offsetof(struct bpf_insn, imm)));
 	/* store btf_obj_fd into insn[insn_idx + 1].imm */
 	emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_7, 32));
 	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7,
 			      sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm)));
-log:
-	if (!gen->log_level)
-		return;
-	emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_8,
-			      offsetof(struct bpf_insn, imm)));
-	emit(gen, BPF_LDX_MEM(BPF_H, BPF_REG_9, BPF_REG_8, sizeof(struct bpf_insn) +
-			      offsetof(struct bpf_insn, imm)));
-	debug_regs(gen, BPF_REG_7, BPF_REG_9, " var (%s:count=%d): imm: %%d, fd: %%d",
-		   relo->name, kdesc->ref);
+	emit(gen, BPF_JMP_IMM(BPF_JSGE, BPF_REG_7, 0, 3));
+clear_src_reg:
+	/* clear bpf_object__relocate_data's src_reg assignment, otherwise we get a verifier failure */
+	reg_mask = src_reg_mask();
+	emit(gen, BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_8, offsetofend(struct bpf_insn, code)));
+	emit(gen, BPF_ALU32_IMM(BPF_AND, BPF_REG_9, reg_mask));
+	emit(gen, BPF_STX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, offsetofend(struct bpf_insn, code)));
+
+	emit_ksym_relo_log(gen, relo, kdesc->ref);
 }
 
 static void emit_relo(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insns)
@@ -749,6 +847,9 @@ static void emit_relo(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn
 	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_8, BPF_PSEUDO_MAP_IDX_VALUE, 0, 0, 0, insn));
 	switch (relo->kind) {
 	case BTF_KIND_VAR:
+		if (relo->is_typeless)
+			emit_relo_ksym_typeless(gen, relo, insn);
+		else
 			emit_relo_ksym_btf(gen, relo, insn);
 		break;
 	case BTF_KIND_FUNC:
@@ -774,12 +875,13 @@ static void cleanup_relos(struct bpf_gen *gen, int insns)
 	int i, insn;
 
 	for (i = 0; i < gen->nr_ksyms; i++) {
-		if (gen->ksyms[i].kind == BTF_KIND_VAR) {
+		/* only close fds for typed ksyms and kfuncs */
+		if (gen->ksyms[i].kind == BTF_KIND_VAR && !gen->ksyms[i].typeless) {
 			/* close fd recorded in insn[insn_idx + 1].imm */
 			insn = gen->ksyms[i].insn;
 			insn += sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm);
 			emit_sys_close_blob(gen, insn);
-		} else { /* BTF_KIND_FUNC */
+		} else if (gen->ksyms[i].kind == BTF_KIND_FUNC) {
 			emit_sys_close_blob(gen, blob_fd_array_off(gen, gen->ksyms[i].off));
 			if (gen->ksyms[i].off < MAX_FD_ARRAY_SZ)
 				gen->nr_fd_array--;

tools/lib/bpf/libbpf.c

@@ -1232,7 +1232,7 @@ static int bpf_object__elf_init(struct bpf_object *obj)
 		 */
 		elf = elf_memory((char *)obj->efile.obj_buf, obj->efile.obj_buf_sz);
 	} else {
-		obj->efile.fd = open(obj->path, O_RDONLY);
+		obj->efile.fd = open(obj->path, O_RDONLY | O_CLOEXEC);
 		if (obj->efile.fd < 0) {
 			char errmsg[STRERR_BUFSIZE], *cp;
 
@@ -6575,17 +6575,14 @@ static int bpf_program__record_externs(struct bpf_program *prog)
 		case RELO_EXTERN_VAR:
 			if (ext->type != EXT_KSYM)
 				continue;
-			if (!ext->ksym.type_id) {
-				pr_warn("typeless ksym %s is not supported yet\n",
-					ext->name);
-				return -ENOTSUP;
-			}
-			bpf_gen__record_extern(obj->gen_loader, ext->name, ext->is_weak,
+			bpf_gen__record_extern(obj->gen_loader, ext->name,
+					       ext->is_weak, !ext->ksym.type_id,
 					       BTF_KIND_VAR, relo->insn_idx);
 			break;
 		case RELO_EXTERN_FUNC:
-			bpf_gen__record_extern(obj->gen_loader, ext->name, ext->is_weak,
-					       BTF_KIND_FUNC, relo->insn_idx);
+			bpf_gen__record_extern(obj->gen_loader, ext->name,
+					       ext->is_weak, false, BTF_KIND_FUNC,
+					       relo->insn_idx);
 			break;
 		default:
 			continue;
@@ -9618,7 +9615,7 @@ static int append_to_file(const char *file, const char *fmt, ...)
 	int fd, n, err = 0;
 	va_list ap;
 
-	fd = open(file, O_WRONLY | O_APPEND, 0);
+	fd = open(file, O_WRONLY | O_APPEND | O_CLOEXEC, 0);
 	if (fd < 0)
 		return -errno;
 
@@ -11263,7 +11260,7 @@ int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz)
 	int fd, err = 0, len;
 	char buf[128];
 
-	fd = open(fcpu, O_RDONLY);
+	fd = open(fcpu, O_RDONLY | O_CLOEXEC);
 	if (fd < 0) {
 		err = -errno;
 		pr_warn("Failed to open cpu mask file %s: %d\n", fcpu, err);

tools/lib/bpf/libbpf_internal.h

@@ -13,6 +13,8 @@
 #include <limits.h>
 #include <errno.h>
 #include <linux/err.h>
+#include <fcntl.h>
+#include <unistd.h>
 #include "libbpf_legacy.h"
 #include "relo_core.h"
 
@@ -491,4 +493,26 @@ static inline bool is_ldimm64_insn(struct bpf_insn *insn)
 	return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
 }
 
+/* if fd is stdin, stdout, or stderr, dup to a fd greater than 2
+ * Takes ownership of the fd passed in, and closes it if calling
+ * fcntl(fd, F_DUPFD_CLOEXEC, 3).
+ */
+static inline int ensure_good_fd(int fd)
+{
+	int old_fd = fd, saved_errno;
+
+	if (fd < 0)
+		return fd;
+	if (fd < 3) {
+		fd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
+		saved_errno = errno;
+		close(old_fd);
+		if (fd < 0) {
+			pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno);
+			errno = saved_errno;
+		}
+	}
+	return fd;
+}
+
 #endif /* __LIBBPF_LIBBPF_INTERNAL_H */

tools/lib/bpf/libbpf_probes.c

@@ -33,7 +33,7 @@ static int get_vendor_id(int ifindex)
 
 	snprintf(path, sizeof(path), "/sys/class/net/%s/device/vendor", ifname);
 
-	fd = open(path, O_RDONLY);
+	fd = open(path, O_RDONLY | O_CLOEXEC);
 	if (fd < 0)
 		return -1;
 

tools/lib/bpf/linker.c

@@ -301,7 +301,7 @@ static int init_output_elf(struct bpf_linker *linker, const char *file)
 	if (!linker->filename)
 		return -ENOMEM;
 
-	linker->fd = open(file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+	linker->fd = open(file, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0644);
 	if (linker->fd < 0) {
 		err = -errno;
 		pr_warn("failed to create '%s': %d\n", file, err);
@@ -556,7 +556,7 @@ static int linker_load_obj_file(struct bpf_linker *linker, const char *filename,
 
 	obj->filename = filename;
 
-	obj->fd = open(filename, O_RDONLY);
+	obj->fd = open(filename, O_RDONLY | O_CLOEXEC);
 	if (obj->fd < 0) {
 		err = -errno;
 		pr_warn("failed to open file '%s': %d\n", filename, err);

tools/lib/bpf/xsk.c

@@ -300,7 +300,7 @@ int xsk_umem__create_v0_0_4(struct xsk_umem **umem_ptr, void *umem_area,
 	if (!umem)
 		return -ENOMEM;
 
-	umem->fd = socket(AF_XDP, SOCK_RAW, 0);
+	umem->fd = socket(AF_XDP, SOCK_RAW | SOCK_CLOEXEC, 0);
 	if (umem->fd < 0) {
 		err = -errno;
 		goto out_umem_alloc;
@@ -549,7 +549,7 @@ static int xsk_get_max_queues(struct xsk_socket *xsk)
 	struct ifreq ifr = {};
 	int fd, err, ret;
 
-	fd = socket(AF_LOCAL, SOCK_DGRAM, 0);
+	fd = socket(AF_LOCAL, SOCK_DGRAM | SOCK_CLOEXEC, 0);
 	if (fd < 0)
 		return -errno;
 
@@ -1046,7 +1046,7 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr,
 	}
 
 	if (umem->refcount++ > 0) {
-		xsk->fd = socket(AF_XDP, SOCK_RAW, 0);
+		xsk->fd = socket(AF_XDP, SOCK_RAW | SOCK_CLOEXEC, 0);
 		if (xsk->fd < 0) {
 			err = -errno;
 			goto out_xsk_alloc;

tools/testing/selftests/bpf/Makefile

@@ -325,7 +325,7 @@ LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h		\
 LSKELS := kfunc_call_test.c fentry_test.c fexit_test.c fexit_sleep.c \
 	test_ringbuf.c atomics.c trace_printk.c trace_vprintk.c
 # Generate both light skeleton and libbpf skeleton for these
-LSKELS_EXTRA := test_ksyms_module.c
+LSKELS_EXTRA := test_ksyms_module.c test_ksyms_weak.c
 SKEL_BLACKLIST += $$(LSKELS)
 
 test_static_linked.skel.h-deps := test_static_linked1.o test_static_linked2.o
@@ -404,7 +404,7 @@ $(TRUNNER_BPF_LSKELS): %.lskel.h: %.o $(BPFTOOL) | $(TRUNNER_OUTPUT)
 	$(Q)$$(BPFTOOL) gen object $$(<:.o=.linked2.o) $$(<:.o=.linked1.o)
 	$(Q)$$(BPFTOOL) gen object $$(<:.o=.linked3.o) $$(<:.o=.linked2.o)
 	$(Q)diff $$(<:.o=.linked2.o) $$(<:.o=.linked3.o)
-	$(Q)$$(BPFTOOL) gen skeleton -L $$(<:.o=.linked3.o) name $$(notdir $$(<:.o=)) > $$@
+	$(Q)$$(BPFTOOL) gen skeleton -L $$(<:.o=.linked3.o) name $$(notdir $$(<:.o=_lskel)) > $$@
 
 $(TRUNNER_BPF_SKELS_LINKED): $(TRUNNER_BPF_OBJS) $(BPFTOOL) | $(TRUNNER_OUTPUT)
 	$$(call msg,LINK-BPF,$(TRUNNER_BINARY),$$(@:.skel.h=.o))

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

@@ -4,13 +4,13 @@
 
 #include "atomics.lskel.h"
 
-static void test_add(struct atomics *skel)
+static void test_add(struct atomics_lskel *skel)
 {
 	int err, prog_fd;
 	__u32 duration = 0, retval;
 	int link_fd;
 
-	link_fd = atomics__add__attach(skel);
+	link_fd = atomics_lskel__add__attach(skel);
 	if (!ASSERT_GT(link_fd, 0, "attach(add)"))
 		return;
 
@@ -36,13 +36,13 @@ static void test_add(struct atomics *skel)
 	close(link_fd);
 }
 
-static void test_sub(struct atomics *skel)
+static void test_sub(struct atomics_lskel *skel)
 {
 	int err, prog_fd;
 	__u32 duration = 0, retval;
 	int link_fd;
 
-	link_fd = atomics__sub__attach(skel);
+	link_fd = atomics_lskel__sub__attach(skel);
 	if (!ASSERT_GT(link_fd, 0, "attach(sub)"))
 		return;
 
@@ -69,13 +69,13 @@ static void test_sub(struct atomics *skel)
 	close(link_fd);
 }
 
-static void test_and(struct atomics *skel)
+static void test_and(struct atomics_lskel *skel)
 {
 	int err, prog_fd;
 	__u32 duration = 0, retval;
 	int link_fd;
 
-	link_fd = atomics__and__attach(skel);
+	link_fd = atomics_lskel__and__attach(skel);
 	if (!ASSERT_GT(link_fd, 0, "attach(and)"))
 		return;
 
@@ -97,13 +97,13 @@ static void test_and(struct atomics *skel)
 	close(link_fd);
 }
 
-static void test_or(struct atomics *skel)
+static void test_or(struct atomics_lskel *skel)
 {
 	int err, prog_fd;
 	__u32 duration = 0, retval;
 	int link_fd;
 
-	link_fd = atomics__or__attach(skel);
+	link_fd = atomics_lskel__or__attach(skel);
 	if (!ASSERT_GT(link_fd, 0, "attach(or)"))
 		return;
 
@@ -126,13 +126,13 @@ static void test_or(struct atomics *skel)
 	close(link_fd);
 }
 
-static void test_xor(struct atomics *skel)
+static void test_xor(struct atomics_lskel *skel)
 {
 	int err, prog_fd;
 	__u32 duration = 0, retval;
 	int link_fd;
 
-	link_fd = atomics__xor__attach(skel);
+	link_fd = atomics_lskel__xor__attach(skel);
 	if (!ASSERT_GT(link_fd, 0, "attach(xor)"))
 		return;
 
@@ -154,13 +154,13 @@ static void test_xor(struct atomics *skel)
 	close(link_fd);
 }
 
-static void test_cmpxchg(struct atomics *skel)
+static void test_cmpxchg(struct atomics_lskel *skel)
 {
 	int err, prog_fd;
 	__u32 duration = 0, retval;
 	int link_fd;
 
-	link_fd = atomics__cmpxchg__attach(skel);
+	link_fd = atomics_lskel__cmpxchg__attach(skel);
 	if (!ASSERT_GT(link_fd, 0, "attach(cmpxchg)"))
 		return;
 
@@ -183,13 +183,13 @@ static void test_cmpxchg(struct atomics *skel)
 	close(link_fd);
 }
 
-static void test_xchg(struct atomics *skel)
+static void test_xchg(struct atomics_lskel *skel)
 {
 	int err, prog_fd;
 	__u32 duration = 0, retval;
 	int link_fd;
 
-	link_fd = atomics__xchg__attach(skel);
+	link_fd = atomics_lskel__xchg__attach(skel);
 	if (!ASSERT_GT(link_fd, 0, "attach(xchg)"))
 		return;
 
@@ -212,10 +212,10 @@ static void test_xchg(struct atomics *skel)
 
 void test_atomics(void)
 {
-	struct atomics *skel;
+	struct atomics_lskel *skel;
 	__u32 duration = 0;
 
-	skel = atomics__open_and_load();
+	skel = atomics_lskel__open_and_load();
 	if (CHECK(!skel, "skel_load", "atomics skeleton failed\n"))
 		return;
 
@@ -243,5 +243,5 @@ void test_atomics(void)
 		test_xchg(skel);
 
 cleanup:
-	atomics__destroy(skel);
+	atomics_lskel__destroy(skel);
 }

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

@@ -6,23 +6,23 @@
 
 void test_fentry_fexit(void)
 {
-	struct fentry_test *fentry_skel = NULL;
-	struct fexit_test *fexit_skel = NULL;
+	struct fentry_test_lskel *fentry_skel = NULL;
+	struct fexit_test_lskel *fexit_skel = NULL;
 	__u64 *fentry_res, *fexit_res;
 	__u32 duration = 0, retval;
 	int err, prog_fd, i;
 
-	fentry_skel = fentry_test__open_and_load();
+	fentry_skel = fentry_test_lskel__open_and_load();
 	if (CHECK(!fentry_skel, "fentry_skel_load", "fentry skeleton failed\n"))
 		goto close_prog;
-	fexit_skel = fexit_test__open_and_load();
+	fexit_skel = fexit_test_lskel__open_and_load();
 	if (CHECK(!fexit_skel, "fexit_skel_load", "fexit skeleton failed\n"))
 		goto close_prog;
 
-	err = fentry_test__attach(fentry_skel);
+	err = fentry_test_lskel__attach(fentry_skel);
 	if (CHECK(err, "fentry_attach", "fentry attach failed: %d\n", err))
 		goto close_prog;
-	err = fexit_test__attach(fexit_skel);
+	err = fexit_test_lskel__attach(fexit_skel);
 	if (CHECK(err, "fexit_attach", "fexit attach failed: %d\n", err))
 		goto close_prog;
 
@@ -44,6 +44,6 @@ void test_fentry_fexit(void)
 	}
 
 close_prog:
-	fentry_test__destroy(fentry_skel);
-	fexit_test__destroy(fexit_skel);
+	fentry_test_lskel__destroy(fentry_skel);
+	fexit_test_lskel__destroy(fexit_skel);
 }

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

@@ -3,19 +3,19 @@
 #include <test_progs.h>
 #include "fentry_test.lskel.h"
 
-static int fentry_test(struct fentry_test *fentry_skel)
+static int fentry_test(struct fentry_test_lskel *fentry_skel)
 {
 	int err, prog_fd, i;
 	__u32 duration = 0, retval;
 	int link_fd;
 	__u64 *result;
 
-	err = fentry_test__attach(fentry_skel);
+	err = fentry_test_lskel__attach(fentry_skel);
 	if (!ASSERT_OK(err, "fentry_attach"))
 		return err;
 
 	/* Check that already linked program can't be attached again. */
-	link_fd = fentry_test__test1__attach(fentry_skel);
+	link_fd = fentry_test_lskel__test1__attach(fentry_skel);
 	if (!ASSERT_LT(link_fd, 0, "fentry_attach_link"))
 		return -1;
 
@@ -31,7 +31,7 @@ static int fentry_test(struct fentry_test *fentry_skel)
 			return -1;
 	}
 
-	fentry_test__detach(fentry_skel);
+	fentry_test_lskel__detach(fentry_skel);
 
 	/* zero results for re-attach test */
 	memset(fentry_skel->bss, 0, sizeof(*fentry_skel->bss));
@@ -40,10 +40,10 @@ static int fentry_test(struct fentry_test *fentry_skel)
 
 void test_fentry_test(void)
 {
-	struct fentry_test *fentry_skel = NULL;
+	struct fentry_test_lskel *fentry_skel = NULL;
 	int err;
 
-	fentry_skel = fentry_test__open_and_load();
+	fentry_skel = fentry_test_lskel__open_and_load();
 	if (!ASSERT_OK_PTR(fentry_skel, "fentry_skel_load"))
 		goto cleanup;
 
@@ -55,5 +55,5 @@ void test_fentry_test(void)
 	ASSERT_OK(err, "fentry_second_attach");
 
 cleanup:
-	fentry_test__destroy(fentry_skel);
+	fentry_test_lskel__destroy(fentry_skel);
 }

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

@@ -10,7 +10,7 @@
 
 static int do_sleep(void *skel)
 {
-	struct fexit_sleep *fexit_skel = skel;
+	struct fexit_sleep_lskel *fexit_skel = skel;
 	struct timespec ts1 = { .tv_nsec = 1 };
 	struct timespec ts2 = { .tv_sec = 10 };
 
@@ -25,16 +25,16 @@ static char child_stack[STACK_SIZE];
 
 void test_fexit_sleep(void)
 {
-	struct fexit_sleep *fexit_skel = NULL;
+	struct fexit_sleep_lskel *fexit_skel = NULL;
 	int wstatus, duration = 0;
 	pid_t cpid;
 	int err, fexit_cnt;
 
-	fexit_skel = fexit_sleep__open_and_load();
+	fexit_skel = fexit_sleep_lskel__open_and_load();
 	if (CHECK(!fexit_skel, "fexit_skel_load", "fexit skeleton failed\n"))
 		goto cleanup;
 
-	err = fexit_sleep__attach(fexit_skel);
+	err = fexit_sleep_lskel__attach(fexit_skel);
 	if (CHECK(err, "fexit_attach", "fexit attach failed: %d\n", err))
 		goto cleanup;
 
@@ -60,7 +60,7 @@ void test_fexit_sleep(void)
 	 */
 	close(fexit_skel->progs.nanosleep_fentry.prog_fd);
 	close(fexit_skel->progs.nanosleep_fexit.prog_fd);
-	fexit_sleep__detach(fexit_skel);
+	fexit_sleep_lskel__detach(fexit_skel);
 
 	/* kill the thread to unwind sys_nanosleep stack through the trampoline */
 	kill(cpid, 9);
@@ -78,5 +78,5 @@ void test_fexit_sleep(void)
 		goto cleanup;
 
 cleanup:
-	fexit_sleep__destroy(fexit_skel);
+	fexit_sleep_lskel__destroy(fexit_skel);
 }

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

@@ -3,19 +3,19 @@
 #include <test_progs.h>
 #include "fexit_test.lskel.h"
 
-static int fexit_test(struct fexit_test *fexit_skel)
+static int fexit_test(struct fexit_test_lskel *fexit_skel)
 {
 	int err, prog_fd, i;
 	__u32 duration = 0, retval;
 	int link_fd;
 	__u64 *result;
 
-	err = fexit_test__attach(fexit_skel);
+	err = fexit_test_lskel__attach(fexit_skel);
 	if (!ASSERT_OK(err, "fexit_attach"))
 		return err;
 
 	/* Check that already linked program can't be attached again. */
-	link_fd = fexit_test__test1__attach(fexit_skel);
+	link_fd = fexit_test_lskel__test1__attach(fexit_skel);
 	if (!ASSERT_LT(link_fd, 0, "fexit_attach_link"))
 		return -1;
 
@@ -31,7 +31,7 @@ static int fexit_test(struct fexit_test *fexit_skel)
 			return -1;
 	}
 
-	fexit_test__detach(fexit_skel);
+	fexit_test_lskel__detach(fexit_skel);
 
 	/* zero results for re-attach test */
 	memset(fexit_skel->bss, 0, sizeof(*fexit_skel->bss));
@@ -40,10 +40,10 @@ static int fexit_test(struct fexit_test *fexit_skel)
 
 void test_fexit_test(void)
 {
-	struct fexit_test *fexit_skel = NULL;
+	struct fexit_test_lskel *fexit_skel = NULL;
 	int err;
 
-	fexit_skel = fexit_test__open_and_load();
+	fexit_skel = fexit_test_lskel__open_and_load();
 	if (!ASSERT_OK_PTR(fexit_skel, "fexit_skel_load"))
 		goto cleanup;
 
@@ -55,5 +55,5 @@ void test_fexit_test(void)
 	ASSERT_OK(err, "fexit_second_attach");
 
 cleanup:
-	fexit_test__destroy(fexit_skel);
+	fexit_test_lskel__destroy(fexit_skel);
 }

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

@@ -7,10 +7,10 @@
 
 static void test_main(void)
 {
-	struct kfunc_call_test *skel;
+	struct kfunc_call_test_lskel *skel;
 	int prog_fd, retval, err;
 
-	skel = kfunc_call_test__open_and_load();
+	skel = kfunc_call_test_lskel__open_and_load();
 	if (!ASSERT_OK_PTR(skel, "skel"))
 		return;
 
@@ -26,7 +26,7 @@ static void test_main(void)
 	ASSERT_OK(err, "bpf_prog_test_run(test2)");
 	ASSERT_EQ(retval, 3, "test2-retval");
 
-	kfunc_call_test__destroy(skel);
+	kfunc_call_test_lskel__destroy(skel);
 }
 
 static void test_subprog(void)

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

@@ -7,6 +7,7 @@
 #include "test_ksyms_btf.skel.h"
 #include "test_ksyms_btf_null_check.skel.h"
 #include "test_ksyms_weak.skel.h"
+#include "test_ksyms_weak.lskel.h"
 
 static int duration;
 
@@ -89,11 +90,11 @@ static void test_weak_syms(void)
 	int err;
 
 	skel = test_ksyms_weak__open_and_load();
-	if (CHECK(!skel, "test_ksyms_weak__open_and_load", "failed\n"))
+	if (!ASSERT_OK_PTR(skel, "test_ksyms_weak__open_and_load"))
 		return;
 
 	err = test_ksyms_weak__attach(skel);
-	if (CHECK(err, "test_ksyms_weak__attach", "skeleton attach failed: %d\n", err))
+	if (!ASSERT_OK(err, "test_ksyms_weak__attach"))
 		goto cleanup;
 
 	/* trigger tracepoint */
@@ -109,6 +110,33 @@ static void test_weak_syms(void)
 	test_ksyms_weak__destroy(skel);
 }
 
+static void test_weak_syms_lskel(void)
+{
+	struct test_ksyms_weak_lskel *skel;
+	struct test_ksyms_weak_lskel__data *data;
+	int err;
+
+	skel = test_ksyms_weak_lskel__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "test_ksyms_weak_lskel__open_and_load"))
+		return;
+
+	err = test_ksyms_weak_lskel__attach(skel);
+	if (!ASSERT_OK(err, "test_ksyms_weak_lskel__attach"))
+		goto cleanup;
+
+	/* trigger tracepoint */
+	usleep(1);
+
+	data = skel->data;
+	ASSERT_EQ(data->out__existing_typed, 0, "existing typed ksym");
+	ASSERT_NEQ(data->out__existing_typeless, -1, "existing typeless ksym");
+	ASSERT_EQ(data->out__non_existent_typeless, 0, "nonexistent typeless ksym");
+	ASSERT_EQ(data->out__non_existent_typed, 0, "nonexistent typed ksym");
+
+cleanup:
+	test_ksyms_weak_lskel__destroy(skel);
+}
+
 void test_ksyms_btf(void)
 {
 	int percpu_datasec;
@@ -136,4 +164,7 @@ void test_ksyms_btf(void)
 
 	if (test__start_subtest("weak_ksyms"))
 		test_weak_syms();
+
+	if (test__start_subtest("weak_ksyms_lskel"))
+		test_weak_syms_lskel();
 }

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

@@ -4,10 +4,11 @@
 #include <test_progs.h>
 #include <network_helpers.h>
 #include "test_ksyms_module.lskel.h"
+#include "test_ksyms_module.skel.h"
 
-void test_ksyms_module(void)
+void test_ksyms_module_lskel(void)
 {
-	struct test_ksyms_module *skel;
+	struct test_ksyms_module_lskel *skel;
 	int retval;
 	int err;
 
@@ -16,8 +17,8 @@ void test_ksyms_module(void)
 		return;
 	}
 
-	skel = test_ksyms_module__open_and_load();
-	if (!ASSERT_OK_PTR(skel, "test_ksyms_module__open_and_load"))
+	skel = test_ksyms_module_lskel__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "test_ksyms_module_lskel__open_and_load"))
 		return;
 	err = bpf_prog_test_run(skel->progs.load.prog_fd, 1, &pkt_v4, sizeof(pkt_v4),
 				NULL, NULL, (__u32 *)&retval, NULL);
@@ -25,6 +26,37 @@ void test_ksyms_module(void)
 		goto cleanup;
 	ASSERT_EQ(retval, 0, "retval");
 	ASSERT_EQ(skel->bss->out_bpf_testmod_ksym, 42, "bpf_testmod_ksym");
+cleanup:
+	test_ksyms_module_lskel__destroy(skel);
+}
+
+void test_ksyms_module_libbpf(void)
+{
+	struct test_ksyms_module *skel;
+	int retval, err;
+
+	if (!env.has_testmod) {
+		test__skip();
+		return;
+	}
+
+	skel = test_ksyms_module__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "test_ksyms_module__open"))
+		return;
+	err = bpf_prog_test_run(bpf_program__fd(skel->progs.load), 1, &pkt_v4,
+				sizeof(pkt_v4), NULL, NULL, (__u32 *)&retval, NULL);
+	if (!ASSERT_OK(err, "bpf_prog_test_run"))
+		goto cleanup;
+	ASSERT_EQ(retval, 0, "retval");
+	ASSERT_EQ(skel->bss->out_bpf_testmod_ksym, 42, "bpf_testmod_ksym");
 cleanup:
 	test_ksyms_module__destroy(skel);
 }
+
+void test_ksyms_module(void)
+{
+	if (test__start_subtest("lskel"))
+		test_ksyms_module_lskel();
+	if (test__start_subtest("libbpf"))
+		test_ksyms_module_libbpf();
+}

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

-// SPDX-License-Identifier: GPL-2.0
-
-#include <test_progs.h>
-#include <network_helpers.h>
-#include "test_ksyms_module.skel.h"
-
-void test_ksyms_module_libbpf(void)
-{
-	struct test_ksyms_module *skel;
-	int retval, err;
-
-	if (!env.has_testmod) {
-		test__skip();
-		return;
-	}
-
-	skel = test_ksyms_module__open_and_load();
-	if (!ASSERT_OK_PTR(skel, "test_ksyms_module__open"))
-		return;
-	err = bpf_prog_test_run(bpf_program__fd(skel->progs.load), 1, &pkt_v4,
-				sizeof(pkt_v4), NULL, NULL, (__u32 *)&retval, NULL);
-	if (!ASSERT_OK(err, "bpf_prog_test_run"))
-		goto cleanup;
-	ASSERT_EQ(retval, 0, "retval");
-	ASSERT_EQ(skel->bss->out_bpf_testmod_ksym, 42, "bpf_testmod_ksym");
-cleanup:
-	test_ksyms_module__destroy(skel);
-}

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

@@ -58,7 +58,7 @@ static int process_sample(void *ctx, void *data, size_t len)
 	}
 }
 
-static struct test_ringbuf *skel;
+static struct test_ringbuf_lskel *skel;
 static struct ring_buffer *ringbuf;
 
 static void trigger_samples()
@@ -90,13 +90,13 @@ void test_ringbuf(void)
 	int page_size = getpagesize();
 	void *mmap_ptr, *tmp_ptr;
 
-	skel = test_ringbuf__open();
+	skel = test_ringbuf_lskel__open();
 	if (CHECK(!skel, "skel_open", "skeleton open failed\n"))
 		return;
 
 	skel->maps.ringbuf.max_entries = page_size;
 
-	err = test_ringbuf__load(skel);
+	err = test_ringbuf_lskel__load(skel);
 	if (CHECK(err != 0, "skel_load", "skeleton load failed\n"))
 		goto cleanup;
 
@@ -154,7 +154,7 @@ void test_ringbuf(void)
 	if (CHECK(!ringbuf, "ringbuf_create", "failed to create ringbuf\n"))
 		goto cleanup;
 
-	err = test_ringbuf__attach(skel);
+	err = test_ringbuf_lskel__attach(skel);
 	if (CHECK(err, "skel_attach", "skeleton attachment failed: %d\n", err))
 		goto cleanup;
 
@@ -292,8 +292,8 @@ void test_ringbuf(void)
 	CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n",
 	      1L, skel->bss->discarded);
 
-	test_ringbuf__detach(skel);
+	test_ringbuf_lskel__detach(skel);
 cleanup:
 	ring_buffer__free(ringbuf);
-	test_ringbuf__destroy(skel);
+	test_ringbuf_lskel__destroy(skel);
 }

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

@@ -598,7 +598,7 @@ static void query_lookup_prog(struct test_sk_lookup *skel)
 
 static void run_lookup_prog(const struct test *t)
 {
-	int server_fds[MAX_SERVERS] = { -1 };
+	int server_fds[] = { [0 ... MAX_SERVERS - 1] = -1 };
 	int client_fd, reuse_conn_fd = -1;
 	struct bpf_link *lookup_link;
 	int i, err;
@@ -1053,7 +1053,7 @@ static void run_sk_assign(struct test_sk_lookup *skel,
 			  struct bpf_program *lookup_prog,
 			  const char *remote_ip, const char *local_ip)
 {
-	int server_fds[MAX_SERVERS] = { -1 };
+	int server_fds[] = { [0 ... MAX_SERVERS - 1] = -1 };
 	struct bpf_sk_lookup ctx;
 	__u64 server_cookie;
 	int i, err;

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

@@ -43,7 +43,7 @@ static int process_sample(void *ctx, void *data, size_t len)
 void test_test_ima(void)
 {
 	char measured_dir_template[] = "/tmp/ima_measuredXXXXXX";
-	struct ring_buffer *ringbuf;
+	struct ring_buffer *ringbuf = NULL;
 	const char *measured_dir;
 	char cmd[256];
 
@@ -85,5 +85,6 @@ void test_test_ima(void)
 	err = system(cmd);
 	CHECK(err, "failed to run command", "%s, errno = %d\n", cmd, errno);
 close_prog:
+	ring_buffer__free(ringbuf);
 	ima__destroy(skel);
 }

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

@@ -10,27 +10,27 @@
 
 void serial_test_trace_printk(void)
 {
+	struct trace_printk_lskel__bss *bss;
 	int err = 0, iter = 0, found = 0;
-	struct trace_printk__bss *bss;
-	struct trace_printk *skel;
+	struct trace_printk_lskel *skel;
 	char *buf = NULL;
 	FILE *fp = NULL;
 	size_t buflen;
 
-	skel = trace_printk__open();
+	skel = trace_printk_lskel__open();
 	if (!ASSERT_OK_PTR(skel, "trace_printk__open"))
 		return;
 
 	ASSERT_EQ(skel->rodata->fmt[0], 'T', "skel->rodata->fmt[0]");
 	skel->rodata->fmt[0] = 't';
 
-	err = trace_printk__load(skel);
+	err = trace_printk_lskel__load(skel);
 	if (!ASSERT_OK(err, "trace_printk__load"))
 		goto cleanup;
 
 	bss = skel->bss;
 
-	err = trace_printk__attach(skel);
+	err = trace_printk_lskel__attach(skel);
 	if (!ASSERT_OK(err, "trace_printk__attach"))
 		goto cleanup;
 
@@ -43,7 +43,7 @@ void serial_test_trace_printk(void)
 
 	/* wait for tracepoint to trigger */
 	usleep(1);
-	trace_printk__detach(skel);
+	trace_printk_lskel__detach(skel);
 
 	if (!ASSERT_GT(bss->trace_printk_ran, 0, "bss->trace_printk_ran"))
 		goto cleanup;
@@ -65,7 +65,7 @@ void serial_test_trace_printk(void)
 		goto cleanup;
 
 cleanup:
-	trace_printk__destroy(skel);
+	trace_printk_lskel__destroy(skel);
 	free(buf);
 	if (fp)
 		fclose(fp);

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

@@ -10,20 +10,20 @@
 
 void serial_test_trace_vprintk(void)
 {
+	struct trace_vprintk_lskel__bss *bss;
 	int err = 0, iter = 0, found = 0;
-	struct trace_vprintk__bss *bss;
-	struct trace_vprintk *skel;
+	struct trace_vprintk_lskel *skel;
 	char *buf = NULL;
 	FILE *fp = NULL;
 	size_t buflen;
 
-	skel = trace_vprintk__open_and_load();
+	skel = trace_vprintk_lskel__open_and_load();
 	if (!ASSERT_OK_PTR(skel, "trace_vprintk__open_and_load"))
 		goto cleanup;
 
 	bss = skel->bss;
 
-	err = trace_vprintk__attach(skel);
+	err = trace_vprintk_lskel__attach(skel);
 	if (!ASSERT_OK(err, "trace_vprintk__attach"))
 		goto cleanup;
 
@@ -36,7 +36,7 @@ void serial_test_trace_vprintk(void)
 
 	/* wait for tracepoint to trigger */
 	usleep(1);
-	trace_vprintk__detach(skel);
+	trace_vprintk_lskel__detach(skel);
 
 	if (!ASSERT_GT(bss->trace_vprintk_ran, 0, "bss->trace_vprintk_ran"))
 		goto cleanup;
@@ -61,7 +61,7 @@ void serial_test_trace_vprintk(void)
 		goto cleanup;
 
 cleanup:
-	trace_vprintk__destroy(skel);
+	trace_vprintk_lskel__destroy(skel);
 	free(buf);
 	if (fp)
 		fclose(fp);

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

@@ -8,11 +8,11 @@
 void test_verif_stats(void)
 {
 	__u32 len = sizeof(struct bpf_prog_info);
+	struct trace_vprintk_lskel *skel;
 	struct bpf_prog_info info = {};
-	struct trace_vprintk *skel;
 	int err;
 
-	skel = trace_vprintk__open_and_load();
+	skel = trace_vprintk_lskel__open_and_load();
 	if (!ASSERT_OK_PTR(skel, "trace_vprintk__open_and_load"))
 		goto cleanup;
 
@@ -24,5 +24,5 @@ void test_verif_stats(void)
 		goto cleanup;
 
 cleanup:
-	trace_vprintk__destroy(skel);
+	trace_vprintk_lskel__destroy(skel);
 }

tools/testing/selftests/bpf/progs/test_ksyms_weak.c

@@ -38,7 +38,7 @@ int pass_handler(const void *ctx)
 	/* tests existing symbols. */
 	rq = (struct rq *)bpf_per_cpu_ptr(&runqueues, 0);
 	if (rq)
-		out__existing_typed = rq->cpu;
+		out__existing_typed = 0;
 	out__existing_typeless = (__u64)&bpf_prog_active;
 
 	/* tests non-existent symbols. */