Messages in this thread | | | Date | Wed, 26 Jun 2019 20:30:34 -0500 | From | Josh Poimboeuf <> | Subject | Re: [PATCH v3 3/4] bpf: Fix ORC unwinding in non-JIT BPF code |
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On Wed, Jun 26, 2019 at 06:22:48PM -0700, Alexei Starovoitov wrote: > On Wed, Jun 26, 2019 at 6:07 PM Josh Poimboeuf <jpoimboe@redhat.com> wrote: > > > > On Wed, Jun 26, 2019 at 05:57:08PM -0700, Alexei Starovoitov wrote: > > > 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. > > > > As I have said many times: > > > > The jump table detection is a generic objtool feature. It makes no > > sense to give a bpf-specific name to a generic objtool feature which can > > be used by other components. > > Nacked-by: Alexei Starovoitov <ast@kernel.org>
Whatever, it's your code...
To the -tip maintainers: patches 1 and 4 are independent of this change and can be merged regardless.
-- Josh
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