From: Peter Zijlstra <peterz@infradead.org>
To: 李则良 <lizeliang.linux@gmail.com>
Cc: "Jürgen Groß" <jgross@suse.com>,
"Thomas Gleixner" <tglx@kernel.org>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
"Kees Cook" <kees@kernel.org>,
"Nathan Chancellor" <nathan@kernel.org>,
"Josh Poimboeuf" <jpoimboe@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/alternatives: gracefully skip unrecognized indirect call instructions
Date: Wed, 12 Aug 2026 13:00:23 +0200 [thread overview]
Message-ID: <20260812110023.GL776954@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <CANd6bgKs8FAkmQ8hLD=qc2dEXiZn8OU5godYXBjGNN8a85XkNQ@mail.gmail.com>
On Wed, Aug 12, 2026 at 05:22:14PM +0800, 李则良 wrote:
> From cd58bd112a6178593c6bc9c0f9b307d6897ae3d0 Mon Sep 17 00:00:00 2001
> From: Zeliang Li <lizeliang.linux@gmail.com>
> Date: Tue, 11 Aug 2026 19:09:09 +0800
> Subject: [PATCH v2] x86/alternative: WARN and skip unrecognized indirect call
> only for non-O2 builds
>
> When the kernel is compiled at a non-default optimization level
> (e.g., KCFLAGS=-O1 or -O0), the compiler may emit call instruction
> patterns that differ from the expected 6-byte sequence
> (opcodes 0xff 0x15 followed by a 32-bit displacement) checked
> by alt_replace_call().
I don't think we want to cater for this. But what actual instruction
sequences is it emitting?
next prev parent reply other threads:[~2026-08-12 11:00 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CANd6bgL=v+uReoQznRGKunZQApwV5ESHAQn2_MOt-J-=cPkm9g@mail.gmail.com>
2026-08-11 11:50 ` [PATCH] x86/alternatives: gracefully skip unrecognized indirect call instructions Jürgen Groß
2026-08-12 9:22 ` 李则良
2026-08-12 11:00 ` Peter Zijlstra [this message]
2026-08-12 11:24 ` H. Peter Anvin
2026-08-12 15:30 ` Borislav Petkov
2026-08-12 17:14 ` 李则良
2026-08-12 19:01 ` H. Peter Anvin
2026-08-12 19:02 ` H. Peter Anvin
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