bpf: Use prog->jited_len in bpf_prog_ksym_set_addr()

Using prog->jited_len is simpler and more accurate than current
estimation (header + header->size).

Also, fix missing prog->jited_len with multi function program. This hasn't
been a real issue before this.

Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220204185742.271030-5-song@kernel.org

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 14199228a6f07feb4a85ae82b4979fae89ca01c7..e3fe53df0a717ed5c3335917ded1c1f6d84d88a9 100644 (file)
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -537,13 +537,10 @@ long bpf_jit_limit_max __read_mostly;
 static void
 bpf_prog_ksym_set_addr(struct bpf_prog *prog)
 {
-       const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog);
-       unsigned long addr = (unsigned long)hdr;
-
        WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
 
        prog->aux->ksym.start = (unsigned long) prog->bpf_func;
-       prog->aux->ksym.end   = addr + hdr->size;
+       prog->aux->ksym.end   = prog->aux->ksym.start + prog->jited_len;
 }
 
 static void

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 1ae41d0cf96c3d4a6267a393694fc7fecca1107d..bbef86cb4e722d5e3d044e664bcc7ab6aa8823ec 100644 (file)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -13067,6 +13067,7 @@ static int jit_subprogs(struct bpf_verifier_env *env)
 
        prog->jited = 1;
        prog->bpf_func = func[0]->bpf_func;
+       prog->jited_len = func[0]->jited_len;
        prog->aux->func = func;
        prog->aux->func_cnt = env->subprog_cnt;
        bpf_prog_jit_attempt_done(prog);