6.12-stable review patch. If anyone has any objections, please let me know.
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From: Xu Kuohai xukuohai@huawei.com
[ Upstream commit 821a3fa32bbe3bc0fa23b3189325d3720a49a24c ]
Only function pointers in a struct_ops structure can be linked to bpf progs, so set the links count to the function pointers count, instead of the total members count in the structure.
Suggested-by: Martin KaFai Lau martin.lau@linux.dev Signed-off-by: Xu Kuohai xukuohai@huawei.com Link: https://lore.kernel.org/r/20241112145849.3436772-3-xukuohai@huaweicloud.com Signed-off-by: Alexei Starovoitov ast@kernel.org Stable-dep-of: 7c8ce4ffb684 ("bpf: Add kernel symbol for struct_ops trampoline") Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/bpf/bpf_struct_ops.c | 35 +++++++++++++++++++++++++---------- 1 file changed, 25 insertions(+), 10 deletions(-)
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c index fda3dd2ee9844..5058d1536c554 100644 --- a/kernel/bpf/bpf_struct_ops.c +++ b/kernel/bpf/bpf_struct_ops.c @@ -32,7 +32,7 @@ struct bpf_struct_ops_map { * (in kvalue.data). */ struct bpf_link **links; - u32 links_cnt; + u32 funcs_cnt; u32 image_pages_cnt; /* image_pages is an array of pages that has all the trampolines * that stores the func args before calling the bpf_prog. @@ -481,11 +481,11 @@ static void bpf_struct_ops_map_put_progs(struct bpf_struct_ops_map *st_map) { u32 i;
- for (i = 0; i < st_map->links_cnt; i++) { - if (st_map->links[i]) { - bpf_link_put(st_map->links[i]); - st_map->links[i] = NULL; - } + for (i = 0; i < st_map->funcs_cnt; i++) { + if (!st_map->links[i]) + break; + bpf_link_put(st_map->links[i]); + st_map->links[i] = NULL; } }
@@ -601,6 +601,7 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key, int prog_fd, err; u32 i, trampoline_start, image_off = 0; void *cur_image = NULL, *image = NULL; + struct bpf_link **plink;
if (flags) return -EINVAL; @@ -639,6 +640,7 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key, udata = &uvalue->data; kdata = &kvalue->data;
+ plink = st_map->links; module_type = btf_type_by_id(btf_vmlinux, st_ops_ids[IDX_MODULE_ID]); for_each_member(i, t, member) { const struct btf_type *mtype, *ptype; @@ -714,7 +716,7 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key, } bpf_link_init(&link->link, BPF_LINK_TYPE_STRUCT_OPS, &bpf_struct_ops_link_lops, prog); - st_map->links[i] = &link->link; + *plink++ = &link->link;
trampoline_start = image_off; err = bpf_struct_ops_prepare_trampoline(tlinks, link, @@ -895,6 +897,19 @@ static int bpf_struct_ops_map_alloc_check(union bpf_attr *attr) return 0; }
+static u32 count_func_ptrs(const struct btf *btf, const struct btf_type *t) +{ + int i; + u32 count; + const struct btf_member *member; + + count = 0; + for_each_member(i, t, member) + if (btf_type_resolve_func_ptr(btf, member->type, NULL)) + count++; + return count; +} + static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr) { const struct bpf_struct_ops_desc *st_ops_desc; @@ -961,9 +976,9 @@ static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr) map = &st_map->map;
st_map->uvalue = bpf_map_area_alloc(vt->size, NUMA_NO_NODE); - st_map->links_cnt = btf_type_vlen(t); + st_map->funcs_cnt = count_func_ptrs(btf, t); st_map->links = - bpf_map_area_alloc(st_map->links_cnt * sizeof(struct bpf_links *), + bpf_map_area_alloc(st_map->funcs_cnt * sizeof(struct bpf_link *), NUMA_NO_NODE); if (!st_map->uvalue || !st_map->links) { ret = -ENOMEM; @@ -994,7 +1009,7 @@ static u64 bpf_struct_ops_map_mem_usage(const struct bpf_map *map) usage = sizeof(*st_map) + vt->size - sizeof(struct bpf_struct_ops_value); usage += vt->size; - usage += btf_type_vlen(vt) * sizeof(struct bpf_links *); + usage += st_map->funcs_cnt * sizeof(struct bpf_link *); usage += PAGE_SIZE; return usage; }