linux-kernel - [PATCH] bpf, x86_32: Fix logic error in BPF

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Date:   Thu, 23 Apr 2020 13:06:37 +0800
From:   Wang YanQing <udknight@...il.com>
To:     daniel@...earbox.net
Cc:     ast@...nel.org, davem@...emloft.net, jiong.wang@...ronome.com,
        kuznet@....inr.ac.ru, tglx@...utronix.de, netdev@...r.kernel.org,
        bpf@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] 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: 836256bf ("x32: bpf: eliminate zero extension code-gen")

Signed-off-by: Wang YanQing <udknight@...il.com>
---
 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 4d2a7a764602..ed34dd16ebc5 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),
-- 
2.17.1