From 9e4e5b5c86661e767f3074bedbbf2ca59f8fbd18 Mon Sep 17 00:00:00 2001
From: Wang YanQing <udknight@gmail.com>
Date: Thu, 26 Jul 2018 00:46:11 +0800
Subject: bpf, x32: Fix regression caused by commit 24dea04767e6
Commit 24dea04767e6 ("bpf, x32: remove ld_abs/ld_ind")
removed the 4 /* Extra space for skb_copy_bits buffer */
from _STACK_SIZE, but it didn't fix the concerned code
in emit_prologue and emit_epilogue, and this error will
bring very strange kernel runtime errors. This patch
fixes it.
Fixes: 24dea04767e6 ("bpf, x32: remove ld_abs/ld_ind")
Reported-by: Meelis Roos <mroos@linux.ee>
Bisected-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Wang YanQing <udknight@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
arch/x86/net/bpf_jit_comp32.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
(limited to 'arch/x86/net')
diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c
index 55799873ebe5..8f6cc71e0848 100644
--- a/arch/x86/net/bpf_jit_comp32.c
+++ b/arch/x86/net/bpf_jit_comp32.c
@@ -1441,8 +1441,8 @@ static void emit_prologue(u8 **pprog, u32 stack_depth)
/* sub esp,STACK_SIZE */
EMIT2_off32(0x81, 0xEC, STACK_SIZE);
- /* sub ebp,SCRATCH_SIZE+4+12*/
- EMIT3(0x83, add_1reg(0xE8, IA32_EBP), SCRATCH_SIZE + 16);
+ /* sub ebp,SCRATCH_SIZE+12*/
+ EMIT3(0x83, add_1reg(0xE8, IA32_EBP), SCRATCH_SIZE + 12);
/* xor ebx,ebx */
EMIT2(0x31, add_2reg(0xC0, IA32_EBX, IA32_EBX));
@@ -1475,8 +1475,8 @@ static void emit_epilogue(u8 **pprog, u32 stack_depth)
/* mov edx,dword ptr [ebp+off]*/
EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX), STACK_VAR(r0[1]));
- /* add ebp,SCRATCH_SIZE+4+12*/
- EMIT3(0x83, add_1reg(0xC0, IA32_EBP), SCRATCH_SIZE + 16);
+ /* add ebp,SCRATCH_SIZE+12*/
+ EMIT3(0x83, add_1reg(0xC0, IA32_EBP), SCRATCH_SIZE + 12);
/* mov ebx,dword ptr [ebp-12]*/
EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EBX), -12);
--
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