[PATCH AUTOSEL 5.6 76/79] bpf, x86_32: Fix logic error in BPF_LDX zero-extension

[Sasha Levin]

From: Wang YanQing <udknight@xxxxxxxxx>

[ Upstream commit 5ca1ca01fae1e90f8d010eb1d83374f28dc11ee6 ]

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

Fixes: 836256bf5f37 ("x32: bpf: eliminate zero extension code-gen")
Signed-off-by: Wang YanQing <udknight@xxxxxxxxx>
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20200423050637.GA4029@udknight
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 arch/x86/net/bpf_jit_comp32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c
index ba7d9ccfc6626..66cd150b7e541 100644
--- 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),
-- 
2.20.1