diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 4d4badb64824..6fba879492a8 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -757,6 +757,7 @@ struct bpf_object { int arena_map_idx; void *arena_data; size_t arena_data_sz; + size_t arena_data_off; void *jumptables_data; size_t jumptables_data_sz; @@ -2991,10 +2992,11 @@ static int init_arena_map_data(struct bpf_object *obj, struct bpf_map *map, void *data, size_t data_sz) { const long page_sz = sysconf(_SC_PAGE_SIZE); + const size_t data_alloc_sz = roundup(data_sz, page_sz); size_t mmap_sz; mmap_sz = bpf_map_mmap_sz(map); - if (roundup(data_sz, page_sz) > mmap_sz) { + if (data_alloc_sz > mmap_sz) { pr_warn("elf: sec '%s': declared ARENA map size (%zu) is too small to hold global __arena variables of size %zu\n", sec_name, mmap_sz, data_sz); return -E2BIG; @@ -3006,6 +3008,9 @@ static int init_arena_map_data(struct bpf_object *obj, struct bpf_map *map, memcpy(obj->arena_data, data, data_sz); obj->arena_data_sz = data_sz; + /* place globals at the end of the arena */ + obj->arena_data_off = mmap_sz - data_alloc_sz; + /* make bpf_map__init_value() work for ARENA maps */ map->mmaped = obj->arena_data; @@ -4663,7 +4668,7 @@ static int bpf_program__record_reloc(struct bpf_program *prog, reloc_desc->type = RELO_DATA; reloc_desc->insn_idx = insn_idx; reloc_desc->map_idx = obj->arena_map_idx; - reloc_desc->sym_off = sym->st_value; + reloc_desc->sym_off = sym->st_value + obj->arena_data_off; map = &obj->maps[obj->arena_map_idx]; pr_debug("prog '%s': found arena map %d (%s, sec %d, off %zu) for insn %u\n", @@ -5624,7 +5629,8 @@ bpf_object__create_maps(struct bpf_object *obj) return err; } if (obj->arena_data) { - memcpy(map->mmaped, obj->arena_data, obj->arena_data_sz); + memcpy(map->mmaped + obj->arena_data_off, obj->arena_data, + obj->arena_data_sz); zfree(&obj->arena_data); } } @@ -14429,7 +14435,10 @@ int bpf_object__load_skeleton(struct bpf_object_skeleton *s) if (!map_skel->mmaped) continue; - *map_skel->mmaped = map->mmaped; + if (map->def.type == BPF_MAP_TYPE_ARENA) + *map_skel->mmaped = map->mmaped + map->obj->arena_data_off; + else + *map_skel->mmaped = map->mmaped; } return 0; diff --git a/tools/testing/selftests/bpf/progs/verifier_arena_large.c b/tools/testing/selftests/bpf/progs/verifier_arena_large.c index bd430a34c3ab..2b8cf2a4d880 100644 --- a/tools/testing/selftests/bpf/progs/verifier_arena_large.c +++ b/tools/testing/selftests/bpf/progs/verifier_arena_large.c @@ -31,16 +31,22 @@ int big_alloc1(void *ctx) if (!page1) return 1; - /* Account for global arena data. */ - if ((u64)page1 != base + PAGE_SIZE) + if ((u64)page1 != base) return 15; *page1 = 1; - page2 = bpf_arena_alloc_pages(&arena, (void __arena *)(ARENA_SIZE - PAGE_SIZE), + page2 = bpf_arena_alloc_pages(&arena, (void __arena *)(ARENA_SIZE - 2 * PAGE_SIZE), 1, NUMA_NO_NODE, 0); if (!page2) return 2; *page2 = 2; + + /* Test for the guard region at the end of the arena. */ + no_page = bpf_arena_alloc_pages(&arena, (void __arena *)ARENA_SIZE - PAGE_SIZE, + 1, NUMA_NO_NODE, 0); + if (no_page) + return 16; + no_page = bpf_arena_alloc_pages(&arena, (void __arena *)ARENA_SIZE, 1, NUMA_NO_NODE, 0); if (no_page)