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From: Kees Cook <keescook@chromium.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	Mark Rutland <mark.rutland@arm.com>,
	Sami Tolvanen <samitolvanen@google.com>
Subject: Re: [PATCH] ftrace,kcfi: Separate ftrace_stub() and ftrace_stub_graph()
Date: Tue, 18 Oct 2022 11:22:14 -0700	[thread overview]
Message-ID: <202210181121.FEF66CA202@keescook> (raw)
In-Reply-To: <Y06/kaxqvcl/QZqj@hirez.programming.kicks-ass.net>

On Tue, Oct 18, 2022 at 05:00:33PM +0200, Peter Zijlstra wrote:
> On Tue, Oct 18, 2022 at 07:28:29AM -0700, Kees Cook wrote:
> 
> > Thanks for solving this! Just for future archeology, can you include
> > the splat (I assume you hit a CFI splat) in the commit log, and/or how
> > you triggered the problem? I usually find it helpful in trying to fix
> > similar issues later, etc.
> 
> Unfortunately I didn't save it; it was a while ago (I sorta lost track
> of this fix for a while since it was stuffed in my fineibt queue).
> 
> But Mark ran it today to confirm on arm64 and there it looks like
> (harvested from IRC):
> 
>   [    3.153082] CFI failure at ftrace_return_to_handler+0xac/0x16c (target: ftrace_stub+0x0/0x14; expected type: 0x0a5d5347)
> 
> I think simply enabling the ftrace boot time tests is enough to trigger
> this.

Ah-ha, perfect. Thanks! (If it's not yet in tip, can you update the
commit log?)

-- 
Kees Cook

  reply	other threads:[~2022-10-18 18:22 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-18 12:35 [PATCH] ftrace,kcfi: Separate ftrace_stub() and ftrace_stub_graph() Peter Zijlstra
2022-10-18 12:36 ` Peter Zijlstra
2022-10-18 13:18 ` Peter Zijlstra
2022-10-18 13:26   ` Mark Rutland
2022-10-18 14:28   ` Kees Cook
2022-10-18 15:00     ` Peter Zijlstra
2022-10-18 18:22       ` Kees Cook [this message]
2022-10-18 14:21 ` Steven Rostedt
2022-10-18 15:02   ` Peter Zijlstra
2022-10-20 15:17 ` [tip: x86/urgent] " tip-bot2 for Peter Zijlstra

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