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Date: Wed, 20 Aug 2025 15:01:34 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Jiri Olsa <olsajiri@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>, Andrii Nakryiko <andrii@kernel.org>,
	bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-trace-kernel@vger.kernel.org, x86@kernel.org,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	Hao Luo <haoluo@google.com>, Steven Rostedt <rostedt@goodmis.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Alan Maguire <alan.maguire@oracle.com>,
	David Laight <David.Laight@aculab.com>,
	Thomas =?iso-8859-1?Q?Wei=DFschuh?= <thomas@t-8ch.de>,
	Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCHv6 perf/core 10/22] uprobes/x86: Add support to optimize
 uprobes
Message-ID: <20250820130134.GK4067720@noisy.programming.kicks-ass.net>
References: <20250720112133.244369-1-jolsa@kernel.org>
 <20250720112133.244369-11-jolsa@kernel.org>
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In-Reply-To: <aKW9Q0cOhNL0XV0R@krava>

On Wed, Aug 20, 2025 at 02:19:15PM +0200, Jiri Olsa wrote:

> > This seems needlessly restrictive. Something like:
> > 
> > is_nop5(const char *buf)
> > {
> > 	struct insn insn;
> > 
> > 	ret = insn_decode_kernel(&insn, buf)
> > 	if (ret < 0)
> > 		return false;
> > 
> > 	if (insn.length != 5)
> > 		return false;
> > 
> > 	if (insn.opcode[0] != 0x0f ||
> > 	    insn.opcode[1] != 0x1f)
> > 	    	return false;
> > 
> > 	return true;
> > }
> > 
> > Should do I suppose.
> 
> ok, looks good, should I respin with this, or is follow up ok?

I cleaned up already; I pushed out these patches to queue/perf/core and
added a few of my own.

I will need to write better Changelogs, and post them, but I need to run
some errants first.