From: Peter Zijlstra <peterz@infradead.org>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Borislav Petkov <bp@suse.de>,
Josh Poimboeuf <jpoimboe@kernel.org>,
linux-kernel@vger.kernel.org,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: CONFIG_RETHUNK int3 filling prevents kprobes in function body
Date: Mon, 5 Sep 2022 17:15:07 +0200 [thread overview]
Message-ID: <YxYSexFjytTCIJ0i@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <YxYRHHuTHjzgCuE8@hirez.programming.kicks-ass.net>
On Mon, Sep 05, 2022 at 05:09:16PM +0200, Peter Zijlstra wrote:
> On Sun, Sep 04, 2022 at 11:07:13PM +0900, Masami Hiramatsu wrote:
> > Hi Peter,
> >
> > I found that the CONFIG_RETHUNK code (path_return) fills the unused bytes
> > with int3 for padding. Unfortunately, this prevents kprobes on the function
> > body after the return code (e.g. branch blocks placed behind the return.)
>
> Prior to that CONFIG_SLS would already use "ret; int3"
FWIW, there is a compiler option pending to also stick an int3 after
every unconditional jmp.
next prev parent reply other threads:[~2022-09-05 15:15 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-04 14:07 Masami Hiramatsu
2022-09-05 14:57 ` Steven Rostedt
2022-09-05 15:10 ` Peter Zijlstra
2022-09-05 15:20 ` Peter Zijlstra
2022-09-06 1:30 ` Masami Hiramatsu
2022-09-05 15:09 ` Peter Zijlstra
2022-09-05 15:15 ` Peter Zijlstra [this message]
2022-09-05 15:52 ` Peter Zijlstra
2022-09-06 1:33 ` Masami Hiramatsu
2022-09-06 8:44 ` Peter Zijlstra
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