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bpf: Use prog->jited_len in bpf_prog_ksym_set_addr()
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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
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Song Liu authored and Alexei Starovoitov committed Feb 8, 2022
1 parent ed2d9e1 commit d00c647
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Showing 2 changed files with 2 additions and 4 deletions.
5 changes: 1 addition & 4 deletions kernel/bpf/core.c
Original file line number Diff line number Diff line change
Expand Up @@ -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
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1 change: 1 addition & 0 deletions kernel/bpf/verifier.c
Original file line number Diff line number Diff line change
Expand Up @@ -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);
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