linux-kernel - Re: [syzbot] KASAN: stack-out-of-bounds Read in profile

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]

Date:   Thu, 3 Jun 2021 15:30:10 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Andi Kleen <ak@...ux.intel.com>
Cc:     Josh Poimboeuf <jpoimboe@...hat.com>,
        syzbot <syzbot+84fe685c02cd112a2ac3@...kaller.appspotmail.com>,
        bp@...en8.de, hpa@...or.com, inglorion@...gle.com,
        linux-kernel@...r.kernel.org, mingo@...hat.com,
        syzkaller-bugs@...glegroups.com, tglx@...utronix.de,
        x86@...nel.org, Andy Lutomirski <luto@...nel.org>
Subject: Re: [syzbot] KASAN: stack-out-of-bounds Read in profile_pc

On Wed, Jun 02, 2021 at 04:35:11PM -0700, Andi Kleen wrote:

> > We could just use ORC to unwind to the next frame.  Though, isn't
> > /proc/profile redundant, compared to all the more sophisticated options
> > nowadays?  Is there still a distinct use case for it or can we just
> > remove it?
> 
> It's still needed for some special cases. For example there is no other
> viable way to profile early boot without a VM
> 
> I would just drop the hack to unwind, at least for the early boot profile
> use case locking profiling is usually not needed.

Surely we can cook up something else there and delete this thing? ftrace
buffers are available really early, it shouldn't be hard to dump some
data in there during boot.