linux-kernel - Re: [PATCH v2 1/1] psi: Fix uaf issue when psi trigger is destroyed while being polled

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: <CAHk-=wj9-9mFcoaD3rdHd+HKYpyTXkkE2iJkPoTTCrp-+sD=ew@mail.gmail.com>
Date:   Tue, 11 Jan 2022 11:34:53 -0800
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Suren Baghdasaryan <surenb@...gle.com>
Cc:     Eric Biggers <ebiggers@...nel.org>,
        Johannes Weiner <hannes@...xchg.org>,
        Tejun Heo <tj@...nel.org>, Zefan Li <lizefan.x@...edance.com>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        Jonathan Corbet <corbet@....net>,
        "open list:DOCUMENTATION" <linux-doc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Cgroups <cgroups@...r.kernel.org>,
        stable <stable@...r.kernel.org>,
        Android Kernel Team <kernel-team@...roid.com>,
        syzbot <syzbot+cdb5dd11c97cc532efad@...kaller.appspotmail.com>
Subject: Re: [PATCH v2 1/1] psi: Fix uaf issue when psi trigger is destroyed
 while being polled

On Tue, Jan 11, 2022 at 11:27 AM Suren Baghdasaryan <surenb@...gle.com> wrote:
>
> Thanks for the explanation!
> So, it sounds like the best (semantically correct) option I have here
> is smp_store_release() to set the pointer, and then smp_load_acquire()
> to read it. Is my understanding correct?

Yeah, that's the clearest one from a memory ordering standpoint, and
is generally also cheap.

                Linus