| Message ID | 20190708124547.3515538-1-arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
| Series | [RFC] Revert "bpf: Fix ORC unwinding in non-JIT BPF code" | expand |
On Mon, Jul 08, 2019 at 02:45:23PM +0200, Arnd Bergmann wrote: > Apparently this was a bit premature, at least I still get this > warning with gcc-8.1: > > kernel/bpf/core.o: warning: objtool: ___bpf_prog_run()+0x44d2: sibling call from callable instruction with modified stack frame > > This reverts commit b22cf36c189f31883ad0238a69ccf82aa1f3b16b. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> Yes, I have been working on a fix. The impact is that ORC unwinding is broken in this function for CONFIG_RETPOLINE=n. I don't think we want to revert this patch though, because that will broaden the impact to the CONFIG_RETPOLINE=y case. Anyway I hope to have fixes soon. -- Josh
On Mon, Jul 8, 2019 at 3:11 PM Josh Poimboeuf <jpoimboe@redhat.com> wrote: > > On Mon, Jul 08, 2019 at 02:45:23PM +0200, Arnd Bergmann wrote: > > Apparently this was a bit premature, at least I still get this > > warning with gcc-8.1: > > > > kernel/bpf/core.o: warning: objtool: ___bpf_prog_run()+0x44d2: sibling call from callable instruction with modified stack frame > > > > This reverts commit b22cf36c189f31883ad0238a69ccf82aa1f3b16b. > > > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > > Yes, I have been working on a fix. > > The impact is that ORC unwinding is broken in this function for > CONFIG_RETPOLINE=n. > > I don't think we want to revert this patch though, because that will > broaden the impact to the CONFIG_RETPOLINE=y case. Anyway I hope to > have fixes soon. Ok, sounds good. Thanks, Arnd
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 7e98f36a14e2..16079550db6d 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 * const jumptable[256] __annotate_jump_table = { + static const void *jumptable[256] = { [0 ... 255] = &&default_label, /* Now overwrite non-defaults ... */ BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), @@ -1558,6 +1558,7 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack) BUG_ON(1); return 0; } +STACK_FRAME_NON_STANDARD(___bpf_prog_run); /* jump table */ #define PROG_NAME(stack_size) __bpf_prog_run##stack_size #define DEFINE_BPF_PROG_RUN(stack_size) \
Apparently this was a bit premature, at least I still get this warning with gcc-8.1: kernel/bpf/core.o: warning: objtool: ___bpf_prog_run()+0x44d2: sibling call from callable instruction with modified stack frame This reverts commit b22cf36c189f31883ad0238a69ccf82aa1f3b16b. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- kernel/bpf/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) -- 2.20.0