[tip:x86/urgent] x86/refcounts: Switch to UD2 for exceptions

From: tip-bot for Kees Cook
Date: Wed Feb 28 2018 - 09:22:37 EST


Commit-ID: cb097be7036aa325adba33d8c41fe77b980b0e77
Gitweb: https://git.kernel.org/tip/cb097be7036aa325adba33d8c41fe77b980b0e77
Author: Kees Cook <keescook@xxxxxxxxxxxx>
AuthorDate: Sun, 25 Feb 2018 08:50:56 -0800
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Wed, 28 Feb 2018 15:18:40 +0100

x86/refcounts: Switch to UD2 for exceptions

As done in commit 3b3a371cc9bc ("x86/debug: Use UD2 for WARN()"), this
switches to UD2 from UD0 to keep disassembly readable.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: 20180225165056.GA11719@beast">https://lkml.kernel.org/r/20180225165056.GA11719@beast

---
arch/x86/include/asm/refcount.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/refcount.h b/arch/x86/include/asm/refcount.h
index d65171120e90..4cf11d88d3b3 100644
--- a/arch/x86/include/asm/refcount.h
+++ b/arch/x86/include/asm/refcount.h
@@ -17,7 +17,7 @@
#define _REFCOUNT_EXCEPTION \
".pushsection .text..refcount\n" \
"111:\tlea %[counter], %%" _ASM_CX "\n" \
- "112:\t" ASM_UD0 "\n" \
+ "112:\t" ASM_UD2 "\n" \
ASM_UNREACHABLE \
".popsection\n" \
"113:\n" \