6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kui-Feng Lee <thinker.li@xxxxxxxxx> [ Upstream commit 9e926acda0c2e21bca431a1818665ddcd6939755 ] Locate the module BTFs for struct_ops maps and progs and pass them to the kernel. This ensures that the kernel correctly resolves type IDs from the appropriate module BTFs. For the map of a struct_ops object, the FD of the module BTF is set to bpf_map to keep a reference to the module BTF. The FD is passed to the kernel as value_type_btf_obj_fd when the struct_ops object is loaded. For a bpf_struct_ops prog, attach_btf_obj_fd of bpf_prog is the FD of a module BTF in the kernel. Signed-off-by: Kui-Feng Lee <thinker.li@xxxxxxxxx> Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx> Link: https://lore.kernel.org/r/20240119225005.668602-13-thinker.li@xxxxxxxxx Signed-off-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx> Stable-dep-of: 04a94133f1b3 ("libbpf: Don't take direct pointers into BTF data from st_ops") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- tools/lib/bpf/bpf.c | 4 +++- tools/lib/bpf/bpf.h | 4 +++- tools/lib/bpf/libbpf.c | 41 ++++++++++++++++++++++++++--------- tools/lib/bpf/libbpf_probes.c | 1 + 4 files changed, 38 insertions(+), 12 deletions(-) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index b0f1913763a33..ee18aea4a7b58 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -169,7 +169,8 @@ int bpf_map_create(enum bpf_map_type map_type, __u32 max_entries, const struct bpf_map_create_opts *opts) { - const size_t attr_sz = offsetofend(union bpf_attr, map_extra); + const size_t attr_sz = offsetofend(union bpf_attr, + value_type_btf_obj_fd); union bpf_attr attr; int fd; @@ -191,6 +192,7 @@ int bpf_map_create(enum bpf_map_type map_type, attr.btf_key_type_id = OPTS_GET(opts, btf_key_type_id, 0); attr.btf_value_type_id = OPTS_GET(opts, btf_value_type_id, 0); attr.btf_vmlinux_value_type_id = OPTS_GET(opts, btf_vmlinux_value_type_id, 0); + attr.value_type_btf_obj_fd = OPTS_GET(opts, value_type_btf_obj_fd, -1); attr.inner_map_fd = OPTS_GET(opts, inner_map_fd, 0); attr.map_flags = OPTS_GET(opts, map_flags, 0); diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 107fef7488682..db0ff8ade19a4 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -51,8 +51,10 @@ struct bpf_map_create_opts { __u32 numa_node; __u32 map_ifindex; + __s32 value_type_btf_obj_fd; + size_t:0; }; -#define bpf_map_create_opts__last_field map_ifindex +#define bpf_map_create_opts__last_field value_type_btf_obj_fd LIBBPF_API int bpf_map_create(enum bpf_map_type map_type, const char *map_name, diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 54f3380010f55..a2b765e419c16 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -518,6 +518,7 @@ struct bpf_map { struct bpf_map_def def; __u32 numa_node; __u32 btf_var_idx; + int mod_btf_fd; __u32 btf_key_type_id; __u32 btf_value_type_id; __u32 btf_vmlinux_value_type_id; @@ -918,22 +919,29 @@ find_member_by_name(const struct btf *btf, const struct btf_type *t, return NULL; } +static int find_ksym_btf_id(struct bpf_object *obj, const char *ksym_name, + __u16 kind, struct btf **res_btf, + struct module_btf **res_mod_btf); + #define STRUCT_OPS_VALUE_PREFIX "bpf_struct_ops_" static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix, const char *name, __u32 kind); static int -find_struct_ops_kern_types(const struct btf *btf, const char *tname, +find_struct_ops_kern_types(struct bpf_object *obj, const char *tname, + struct module_btf **mod_btf, const struct btf_type **type, __u32 *type_id, const struct btf_type **vtype, __u32 *vtype_id, const struct btf_member **data_member) { const struct btf_type *kern_type, *kern_vtype; const struct btf_member *kern_data_member; + struct btf *btf; __s32 kern_vtype_id, kern_type_id; __u32 i; - kern_type_id = btf__find_by_name_kind(btf, tname, BTF_KIND_STRUCT); + kern_type_id = find_ksym_btf_id(obj, tname, BTF_KIND_STRUCT, + &btf, mod_btf); if (kern_type_id < 0) { pr_warn("struct_ops init_kern: struct %s is not found in kernel BTF\n", tname); @@ -987,14 +995,16 @@ static bool bpf_map__is_struct_ops(const struct bpf_map *map) } /* Init the map's fields that depend on kern_btf */ -static int bpf_map__init_kern_struct_ops(struct bpf_map *map, - const struct btf *btf, - const struct btf *kern_btf) +static int bpf_map__init_kern_struct_ops(struct bpf_map *map) { const struct btf_member *member, *kern_member, *kern_data_member; const struct btf_type *type, *kern_type, *kern_vtype; __u32 i, kern_type_id, kern_vtype_id, kern_data_off; + struct bpf_object *obj = map->obj; + const struct btf *btf = obj->btf; struct bpf_struct_ops *st_ops; + const struct btf *kern_btf; + struct module_btf *mod_btf; void *data, *kern_data; const char *tname; int err; @@ -1002,16 +1012,19 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map, st_ops = map->st_ops; type = st_ops->type; tname = st_ops->tname; - err = find_struct_ops_kern_types(kern_btf, tname, + err = find_struct_ops_kern_types(obj, tname, &mod_btf, &kern_type, &kern_type_id, &kern_vtype, &kern_vtype_id, &kern_data_member); if (err) return err; + kern_btf = mod_btf ? mod_btf->btf : obj->btf_vmlinux; + pr_debug("struct_ops init_kern %s: type_id:%u kern_type_id:%u kern_vtype_id:%u\n", map->name, st_ops->type_id, kern_type_id, kern_vtype_id); + map->mod_btf_fd = mod_btf ? mod_btf->fd : -1; map->def.value_size = kern_vtype->size; map->btf_vmlinux_value_type_id = kern_vtype_id; @@ -1087,6 +1100,8 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map, return -ENOTSUP; } + if (mod_btf) + prog->attach_btf_obj_fd = mod_btf->fd; prog->attach_btf_id = kern_type_id; prog->expected_attach_type = kern_member_idx; @@ -1129,8 +1144,7 @@ static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj) if (!bpf_map__is_struct_ops(map)) continue; - err = bpf_map__init_kern_struct_ops(map, obj->btf, - obj->btf_vmlinux); + err = bpf_map__init_kern_struct_ops(map); if (err) return err; } @@ -5133,8 +5147,13 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b create_attr.numa_node = map->numa_node; create_attr.map_extra = map->map_extra; - if (bpf_map__is_struct_ops(map)) + if (bpf_map__is_struct_ops(map)) { create_attr.btf_vmlinux_value_type_id = map->btf_vmlinux_value_type_id; + if (map->mod_btf_fd >= 0) { + create_attr.value_type_btf_obj_fd = map->mod_btf_fd; + create_attr.map_flags |= BPF_F_VTYPE_BTF_OBJ_FD; + } + } if (obj->btf && btf__fd(obj->btf) >= 0) { create_attr.btf_fd = btf__fd(obj->btf); @@ -9444,7 +9463,9 @@ static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attac *btf_obj_fd = 0; *btf_type_id = 1; } else { - err = find_kernel_btf_id(prog->obj, attach_name, attach_type, btf_obj_fd, btf_type_id); + err = find_kernel_btf_id(prog->obj, attach_name, + attach_type, btf_obj_fd, + btf_type_id); } if (err) { pr_warn("prog '%s': failed to find kernel BTF type ID of '%s': %d\n", diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c index 9c4db90b92b6b..98373d126d9d7 100644 --- a/tools/lib/bpf/libbpf_probes.c +++ b/tools/lib/bpf/libbpf_probes.c @@ -326,6 +326,7 @@ static int probe_map_create(enum bpf_map_type map_type) case BPF_MAP_TYPE_STRUCT_OPS: /* we'll get -ENOTSUPP for invalid BTF type ID for struct_ops */ opts.btf_vmlinux_value_type_id = 1; + opts.value_type_btf_obj_fd = -1; exp_err = -524; /* -ENOTSUPP */ break; case BPF_MAP_TYPE_BLOOM_FILTER: -- 2.43.0
