linux-kernel - Re: [PATCH 03/21] rcu: Add a note about noinstr VS unsafe eqs functions

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: <20220519150406.GB618878@lothringen>
Date:   Thu, 19 May 2022 17:04:06 +0200
From:   Frederic Weisbecker <frederic@...nel.org>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     LKML <linux-kernel@...r.kernel.org>, Phil Auld <pauld@...hat.com>,
        Alex Belits <abelits@...vell.com>,
        Nicolas Saenz Julienne <nsaenz@...nel.org>,
        Xiongfeng Wang <wangxiongfeng2@...wei.com>,
        Neeraj Upadhyay <quic_neeraju@...cinc.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Yu Liao <liaoyu15@...wei.com>,
        Boqun Feng <boqun.feng@...il.com>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Marcelo Tosatti <mtosatti@...hat.com>,
        Paul Gortmaker <paul.gortmaker@...driver.com>,
        Uladzislau Rezki <uladzislau.rezki@...y.com>,
        Joel Fernandes <joel@...lfernandes.org>
Subject: Re: [PATCH 03/21] rcu: Add a note about noinstr VS unsafe eqs
 functions

On Thu, May 19, 2022 at 05:00:26PM +0200, Peter Zijlstra wrote:
> On Tue, May 03, 2022 at 12:00:33PM +0200, Frederic Weisbecker wrote:
> > @@ -895,6 +899,10 @@ static void noinstr rcu_eqs_exit(bool user)
> >   *
> >   * If you add or remove a call to rcu_idle_exit(), be sure to test with
> >   * CONFIG_RCU_EQS_DEBUG=y.
> > + *
> > + * FIXME: This function should be noinstr but the below local_irq_save() is
> > + * unsafe because it involves illegal RCU uses through tracing and lockdep.
> > + * This must be fixed first.
> >   */
> >  void rcu_idle_exit(void)
> >  {
> 
> Urgh, except this one... I'm sure I fixed that at some point. Clearly
> that never made it in :/

Most definetly the trickiest one...