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From: Andi Kleen <andi@firstfloor.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Fangrui Song <maskray@sourceware.org>,
	linux-toolchains@vger.kernel.org,
	 linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Concerns about SFrame viability for userspace stack walking
Date: Thu, 30 Oct 2025 10:53:13 -0700	[thread overview]
Message-ID: <87zf982s52.fsf@linux.intel.com> (raw)
In-Reply-To: <20251030102626.GR3245006@noisy.programming.kicks-ass.net> (Peter Zijlstra's message of "Thu, 30 Oct 2025 11:26:26 +0100")

Peter Zijlstra <peterz@infradead.org> writes:
>
> So the SFrame unwinder is fairly simple code, but what does an .eh_frame
> unwinder look like? Having read most of the links in your email, there
> seem to be references to DWARF byte code interpreters and stuff like
> that.

Here's Jan Beulich's Linux implementation. The x86 version was
removed, but it lives on for ARC:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arc/kernel/unwind.c

SH also has another one from Matt Flemming:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/sh/kernel/dwarf.c

IMNSHO the whole sframe effort is misguided because all the major ISAs do have
shadow stack hardware support now which is generally a better option. 
It would be better to invest effort in deploying that widely.

-Andi

  parent reply	other threads:[~2025-10-30 17:53 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-30  6:53 Concerns about SFrame viability for userspace stack walking Fangrui Song
2025-10-30  7:30 ` Jakub Jelinek
2025-10-30  7:50   ` Fangrui Song
2025-10-30  8:05     ` Jakub Jelinek
2025-10-31  2:51       ` Fangrui Song
2025-10-30 10:26 ` Peter Zijlstra
2025-10-30 16:48   ` Fangrui Song
2025-10-30 17:03     ` Jose E. Marchesi
2025-10-31  4:22       ` Fangrui Song
2025-10-31 14:37         ` Jose E. Marchesi
2025-10-30 17:33     ` Steven Rostedt
2025-10-31  5:28       ` Fangrui Song
2025-10-30 18:22     ` Peter Zijlstra
2025-10-30 17:53   ` Andi Kleen [this message]
2025-10-30 18:07     ` Mark Brown
2025-10-30 18:31       ` Andi Kleen
2025-10-30 18:45         ` Mark Brown
2025-10-31  8:24           ` Fangrui Song
2025-10-30 18:57         ` Peter Zijlstra
2025-10-31 11:46           ` Mark Brown
2025-10-30 14:47 ` Jose E. Marchesi
2025-11-04  9:21 ` Indu
2025-11-05  8:21   ` Fangrui Song
2025-11-06  0:44     ` Indu Bhagat
2025-11-06  7:51       ` Florian Weimer
2025-11-06 21:02         ` Indu Bhagat
2025-11-06  9:20       ` Fangrui Song
2025-11-06 20:42         ` Indu Bhagat
2025-11-09  0:23           ` Fangrui Song
2025-12-01  9:04 ` Fangrui Song

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