This is a note to let you know that I've just added the patch titled
x86/kprobes: Retrieve correct opcode for group instruction
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-kprobes-retrieve-correct-opcode-for-group-instruction.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From stable-owner@xxxxxxxxxxxxxxx Wed Jul 5 08:48:03 2023
From: Li Huafei <lihuafei1@xxxxxxxxxx>
Date: Wed, 5 Jul 2023 14:46:47 +0800
Subject: x86/kprobes: Retrieve correct opcode for group instruction
To: <stable@xxxxxxxxxxxxxxx>
Cc: <gregkh@xxxxxxxxxxxxxxxxxxx>, <mhiramat@xxxxxxxxxx>, <tglx@xxxxxxxxxxxxx>, <mingo@xxxxxxxxxx>, <bp@xxxxxxxxx>, <x86@xxxxxxxxxx>, <hpa@xxxxxxxxx>, <sashal@xxxxxxxxxx>, <peterz@xxxxxxxxxxxxx>, <linux-kernel@xxxxxxxxxxxxxxx>, <xukuohai@xxxxxxxxxx>, <natechancellor@xxxxxxxxx>, <ndesaulniers@xxxxxxxxxx>, <rostedt@xxxxxxxxxxx>, <weiyongjun1@xxxxxxxxxx>, <gustavoars@xxxxxxxxxx>, <namit@xxxxxxxxxx>, <laijs@xxxxxxxxxxxxxxxxx>, <clang-built-linux@xxxxxxxxxxxxxxxx>, <lihuafei1@xxxxxxxxxx>
Message-ID: <20230705064653.226811-4-lihuafei1@xxxxxxxxxx>
From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
[ Upstream commit d60ad3d46f1d04a282c56159f1deb675c12733fd ]
Since the opcodes start from 0xff are group5 instruction group which is
not 2 bytes opcode but the extended opcode determined by the MOD/RM byte.
The commit abd82e533d88 ("x86/kprobes: Do not decode opcode in resume_execution()")
used insn->opcode.bytes[1], but that is not correct. We have to refer
the insn->modrm.bytes[1] instead.
Fixes: abd82e533d88 ("x86/kprobes: Do not decode opcode in resume_execution()")
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/161469872400.49483.18214724458034233166.stgit@devnote2
Signed-off-by: Li Huafei <lihuafei1@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/kprobes/core.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -464,7 +464,11 @@ static void set_resume_flags(struct kpro
break;
#endif
case 0xff:
- opcode = insn->opcode.bytes[1];
+ /*
+ * Since the 0xff is an extended group opcode, the instruction
+ * is determined by the MOD/RM byte.
+ */
+ opcode = insn->modrm.bytes[0];
if ((opcode & 0x30) == 0x10) {
/*
* call absolute, indirect
Patches currently in stable-queue which might be from stable-owner@xxxxxxxxxxxxxxx are
queue-5.10/x86-kprobes-update-kcb-status-flag-after-singlestepping.patch
queue-5.10/x86-kprobes-fix-to-identify-indirect-jmp-and-others-using-range-case.patch
queue-5.10/x86-kprobes-fix-jng-jnle-emulation.patch
queue-5.10/x86-kprobes-retrieve-correct-opcode-for-group-instruction.patch
queue-5.10/x86-kprobes-use-int3-instead-of-debug-trap-for-single-step.patch
queue-5.10/x86-kprobes-do-not-decode-opcode-in-resume_execution.patch
queue-5.10/x86-kprobes-identify-far-indirect-jmp-correctly.patch
queue-5.10/kprobes-x86-fix-fall-through-warnings-for-clang.patch
queue-5.10/x86-kprobes-move-inline-to-the-beginning-of-the-kprobe_is_ss-declaration.patch
