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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Mon, 10 Feb 2020 09:46:26 -0800
Message-ID: <CAHk-=wh05FniF0xJYqcFrmGeCvOJUqR0UL4jTC-_LvpsfNCkNw@mail.gmail.com>
Subject: Re: [PATCH v8 07/11] proc: flush task dcache entries from all procfs instances
To:     Alexey Gladkov <gladkov.alexey@gmail.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Kernel Hardening <kernel-hardening@lists.openwall.com>,
        Linux API <linux-api@vger.kernel.org>,
        Linux FS Devel <linux-fsdevel@vger.kernel.org>,
        Linux Security Module <linux-security-module@vger.kernel.org>,
        Akinobu Mita <akinobu.mita@gmail.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andy Lutomirski <luto@kernel.org>,
        Daniel Micay <danielmicay@gmail.com>,
        Djalal Harouni <tixxdz@gmail.com>,
        "Dmitry V . Levin" <ldv@altlinux.org>,
        "Eric W . Biederman" <ebiederm@xmission.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Ingo Molnar <mingo@kernel.org>,
        "J . Bruce Fields" <bfields@fieldses.org>,
        Jeff Layton <jlayton@poochiereds.net>,
        Jonathan Corbet <corbet@lwn.net>,
        Kees Cook <keescook@chromium.org>,
        Oleg Nesterov <oleg@redhat.com>,
        Solar Designer <solar@openwall.com>
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On Mon, Feb 10, 2020 at 7:06 AM Alexey Gladkov <gladkov.alexey@gmail.com> wrote:
>
> This allows to flush dcache entries of a task on multiple procfs mounts
> per pid namespace.
>
> The RCU lock is used because the number of reads at the task exit time
> is much larger than the number of procfs mounts.

Ok, this looks better to me than the previous version.

But that may be the "pee-in-the-snow" effect, and I _really_ want
others to take a good look at the whole series.

The right people seem to be cc'd, but this is pretty core, and /proc
has a tendency to cause interesting issues because of how it's
involved in a lot of areas indirectly.

Al, Oleg, Andy, Eric?

             Linus