linux-kernel - Re: Concerns about SFrame viability for userspace stack walking

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <87zf982s52.fsf@linux.intel.com>
Date: Thu, 30 Oct 2025 10:53:13 -0700
From: Andi Kleen <andi@...stfloor.org>
To: Peter Zijlstra <peterz@...radead.org>
Cc: Fangrui Song <maskray@...rceware.org>,
  linux-toolchains@...r.kernel.org,  linux-perf-users@...r.kernel.org,
  linux-kernel@...r.kernel.org
Subject: Re: Concerns about SFrame viability for userspace stack walking

Peter Zijlstra <peterz@...radead.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