linux-kernel - Re: [PATCH] x86/kprobes: Fix 1 byte conditional jump target

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Message-ID: <b1300308-8f29-fa73-5542-25d06925ca84@intel.com>
Date:   Tue, 7 Feb 2023 22:56:48 -0800
From:   Dave Hansen <dave.hansen@...el.com>
To:     Nadav Amit <namit@...are.com>
Cc:     "Masami Hiramatsu (Google)" <mhiramat@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        X86 ML <x86@...nel.org>,
        kernel list <linux-kernel@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH] x86/kprobes: Fix 1 byte conditional jump target

On 2/7/23 22:34, Nadav Amit wrote:
> As you said, I guess the change you and Masami proposed can be done on top of
> this patch, which is (and was) only intended to fix the bug, and should
> therefore go into 6.2.

Nadav,
	
To fix this issue, you proposed:

	p->ainsn.rel32 = *(s8 *)&insn->immediate.value;

But, this is, um, rather obfuscated and potentially less correct
compared to:

	p->ainsn.rel32 = insn->immediate.value;

I'd appreciate it if you could update your patch to do this simpler
thing and resend, unless there is a strong reason to do what you
originally proposed.