linux-kernel - Re: [patch V6 07/11] rseq: Implement time slice extension enforcement timer

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] [day] [month] [year] [list]

Message-ID: <7B4AF4F8-EE20-44CC-BC79-693529F19BA6@oracle.com>
Date: Tue, 16 Dec 2025 17:55:07 +0000
From: Prakash Sangappa <prakash.sangappa@...cle.com>
To: Randy Dunlap <rdunlap@...radead.org>
CC: Thomas Gleixner <tglx@...utronix.de>, LKML <linux-kernel@...r.kernel.org>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        "Paul E. McKenney"
	<paulmck@...nel.org>,
        Boqun Feng <boqun.feng@...il.com>, Jonathan Corbet
	<corbet@....net>,
        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" <linux-arch@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>, Ron Geva <rongevarg@...il.com>,
        Waiman
 Long <longman@...hat.com>
Subject: Re: [patch V6 07/11] rseq: Implement time slice extension enforcement
 timer



> On Dec 15, 2025, at 11:18 PM, Randy Dunlap <rdunlap@...radead.org> wrote:
> 
> Ouch. Would you mind rearranging parts of the first sentence?
> 
> On 12/15/25 10:24 AM, Thomas Gleixner wrote:
>> --- a/Documentation/admin-guide/sysctl/kernel.rst
>> +++ b/Documentation/admin-guide/sysctl/kernel.rst
>> @@ -1228,6 +1228,14 @@ reboot-cmd (SPARC only)
>> ROM/Flash boot loader. Maybe to tell it what to do after
>> rebooting. ???
>> 
>> +rseq_slice_extension_nsec
>> +=========================
>> +
>> +A task can request to delay its scheduling if it is in a critical section
>> +via the prctl(PR_RSEQ_SLICE_EXTENSION_SET) mechanism. This sets the maximum
>> +allowed extension in nanoseconds before scheduling of the task is enforced.
>> +Default value is 30000ns (30us). The possible range is 10000ns (10us) to
>> +50000ns (50us).
> 
> Maybe
> A task that is in a critical section can request to delay its scheduling via
> the prctl(PR_RSEQ_SLICE_EXTENSION_SET) mechanism.
> 

Well, this prctl call is to enable the time slice extension mechanism for the thread.
Actually requesting to delay scheduling(time slice extension) is done 
by updating a member in rseq structure. Perhaps this needs to be clarified.

-Prakash

> -- 
> ~Randy
>