bpf, x86_32: Fix logic error in BPF_LDX zero-extension

When verifier_zext is true, we don't need to emit code
for zero-extension.

Fixes: b437dbcbc81b ("x32: bpf: eliminate zero extension code-gen")
Signed-off-by: Wang YanQing <udknight@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200423050637.GA4029@udknight

diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c
index ba7d9ccfc66263c21c3a50c8af948f330c0ad7c3..66cd150b7e541d77302819298284ec3b81c54b12 100644 (file)
--- a/arch/x86/net/bpf_jit_comp32.c
+++ b/arch/x86/net/bpf_jit_comp32.c
@@ -1847,7 +1847,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
                        case BPF_B:
                        case BPF_H:
                        case BPF_W:
-                               if (!bpf_prog->aux->verifier_zext)
+                               if (bpf_prog->aux->verifier_zext)
                                        break;
                                if (dstk) {
                                        EMIT3(0xC7, add_1reg(0x40, IA32_EBP),