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    SubjectRe: [PATCH v3 3/4] bpf: Fix ORC unwinding in non-JIT BPF code
    On Wed, Jun 26, 2019 at 5:36 PM Josh Poimboeuf <jpoimboe@redhat.com> wrote:
    >
    > Objtool previously ignored ___bpf_prog_run() because it didn't
    > understand the jump table. This resulted in the ORC unwinder not being
    > able to unwind through non-JIT BPF code.
    >
    > Now that objtool knows how to read jump tables, remove the whitelist and
    > rename the variable to "jump_table" so objtool can recognize it.
    >
    > Fixes: d15d356887e7 ("perf/x86: Make perf callchains work without CONFIG_FRAME_POINTER")
    > Reported-by: Song Liu <songliubraving@fb.com>
    > Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
    > ---
    > kernel/bpf/core.c | 5 ++---
    > 1 file changed, 2 insertions(+), 3 deletions(-)
    >
    > diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
    > index 080e2bb644cc..ff66294882f8 100644
    > --- a/kernel/bpf/core.c
    > +++ b/kernel/bpf/core.c
    > @@ -1299,7 +1299,7 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack)
    > {
    > #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y
    > #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z
    > - static const void *jumptable[256] = {
    > + static const void *jump_table[256] = {
    > [0 ... 255] = &&default_label,
    > /* Now overwrite non-defaults ... */
    > BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL),
    > @@ -1315,7 +1315,7 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack)
    > #define CONT_JMP ({ insn++; goto select_insn; })
    >
    > select_insn:
    > - goto *jumptable[insn->code];
    > + goto *jump_table[insn->code];

    I thought we were clear that it is a nack?
    Either live it alone or rename to something like jump_table_bpf_interpreter
    or bpf_interpreter_jump_table.

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