linux-kernel - Re: [patch V6 06/11] rseq: Implement syscall entry work for time slice extensions

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: <87ms3fbf1b.ffs@tglx>
Date: Thu, 18 Dec 2025 23:28:48 +0100
From: Thomas Gleixner <tglx@...utronix.de>
To: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>, LKML
 <linux-kernel@...r.kernel.org>
Cc: "Paul E. McKenney" <paulmck@...nel.org>, Boqun Feng
 <boqun.feng@...il.com>, Jonathan Corbet <corbet@....net>, Prakash Sangappa
 <prakash.sangappa@...cle.com>, Madadi Vineeth Reddy
 <vineethr@...ux.ibm.com>, K Prateek Nayak <kprateek.nayak@....com>, Steven
 Rostedt <rostedt@...dmis.org>, Sebastian Andrzej Siewior
 <bigeasy@...utronix.de>, Arnd Bergmann <arnd@...db.de>,
 linux-arch@...r.kernel.org, Randy Dunlap <rdunlap@...radead.org>, Peter
 Zijlstra <peterz@...radead.org>, Ron Geva <rongevarg@...il.com>, Waiman
 Long <longman@...hat.com>
Subject: Re: [patch V6 06/11] rseq: Implement syscall entry work for time
 slice extensions

On Tue, Dec 16 2025 at 10:05, Mathieu Desnoyers wrote:
> On 2025-12-15 13:24, Thomas Gleixner wrote:
> [...]
>> 
>> If the code detects inconsistent user space that result in a SIGSEGV for
>> the application.
>
> With these last updates that allow userspace to call arbitrary system
> calls to terminate the grant, the only scenario which triggers SIGSEGV
> is if the put_user() storing to the rseq area fails. Perhaps we should

Nope. There is also the debug path which will catch offenders which
fiddle with the state.

Thanks,

        tglx