From: Dave Hansen <dave.hansen@intel.com>
To: Nadav Amit <nadav.amit@gmail.com>, Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Nadav Amit <namit@vmware.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] x86/kprobes: Fix 1 byte conditional jump target
Date: Mon, 6 Feb 2023 10:42:31 -0800 [thread overview]
Message-ID: <a75c134d-8278-b17c-e05e-409b70ad15b0@intel.com> (raw)
In-Reply-To: <20230204210807.3930-1-namit@vmware.com>
On 2/4/23 13:08, Nadav Amit wrote:
> --- a/arch/x86/kernel/kprobes/core.c
> +++ b/arch/x86/kernel/kprobes/core.c
> @@ -625,7 +625,7 @@ static int prepare_emulation(struct kprobe *p, struct insn *insn)
> /* 1 byte conditional jump */
> p->ainsn.emulate_op = kprobe_emulate_jcc;
> p->ainsn.jcc.type = opcode & 0xf;
> - p->ainsn.rel32 = *(char *)insn->immediate.bytes;
> + p->ainsn.rel32 = *(s8 *)&insn->immediate.value;
> break;
This new code is at least consistent with what the other code in that
function does with 1-byte immediates. But, I'm curious what the point
is about going through the 's8' type.
What's wrong with:
p->ainsn.rel32 = insn->immediate.value;
? Am I missing something subtle?
next prev parent reply other threads:[~2023-02-06 18:42 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-04 21:08 [PATCH] x86/kprobes: Fix 1 byte conditional jump target Nadav Amit
2023-02-05 7:49 ` Nadav Amit
2023-02-06 14:19 ` Masami Hiramatsu
2023-02-06 14:18 ` Masami Hiramatsu
2023-02-06 18:42 ` Dave Hansen [this message]
2023-02-06 19:05 ` Nadav Amit
2023-02-06 22:38 ` Dave Hansen
2023-02-07 0:54 ` Masami Hiramatsu
2023-02-07 15:21 ` Masami Hiramatsu
2023-02-07 15:33 ` Dave Hansen
2023-02-08 6:34 ` Nadav Amit
2023-02-08 6:56 ` Dave Hansen
2023-02-08 6:58 ` Nadav Amit
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