All of lore.kernel.org
 help / color / mirror / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>,
	Borislav Petkov <bp@suse.de>,
	Josh Poimboeuf <jpoimboe@kernel.org>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>
Subject: Re: CONFIG_RETHUNK int3 filling prevents kprobes in function body
Date: Mon, 5 Sep 2022 17:10:27 +0200	[thread overview]
Message-ID: <YxYRYwZ/zYO+u1ij@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20220905105758.176734eb@gandalf.local.home>

On Mon, Sep 05, 2022 at 10:57:58AM -0400, Steven Rostedt wrote:
> On Sun, 4 Sep 2022 23:07:13 +0900
> Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:
> 
> > Can we use another instruction for padding instead of INT3? (e.g. NOP or UD2)
> > 
> > Or, can I expect the instruction length in __return_sites[] are always 5?
> > If so, I can just skip 5 bytes if the address is in __return_sites[].
> 
> Perhaps another option is to have a table of where the padding is placed
> (tagged), and that kprobes could check to see if the int3 is due to this
> padding or not?

I don't see need for that. If you want to be strict you can simply
follow the branches found earlier, if you want to be lazy, you can
decode until you run out of the symbol size.

  reply	other threads:[~2022-09-05 15:11 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-04 14:07 CONFIG_RETHUNK int3 filling prevents kprobes in function body Masami Hiramatsu
2022-09-05 14:57 ` Steven Rostedt
2022-09-05 15:10   ` Peter Zijlstra [this message]
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
2022-09-05 15:52   ` Peter Zijlstra
2022-09-06  1:33     ` Masami Hiramatsu
2022-09-06  8:44       ` Peter Zijlstra

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YxYRYwZ/zYO+u1ij@hirez.programming.kicks-ass.net \
    --to=peterz@infradead.org \
    --cc=bp@suse.de \
    --cc=jpoimboe@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mhiramat@kernel.org \
    --cc=mingo@kernel.org \
    --cc=rostedt@goodmis.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.