linux-kernel - Re: [RFC 5/5] pm: remove kernel thread freezing

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]

Date:   Wed, 4 Oct 2017 01:03:54 +0000
From:   Bart Van Assche <Bart.VanAssche@....com>
To:     "rjw@...ysocki.net" <rjw@...ysocki.net>,
        "mcgrof@...nel.org" <mcgrof@...nel.org>
CC:     "boris.ostrovsky@...cle.com" <boris.ostrovsky@...cle.com>,
        "ONeukum@...e.com" <ONeukum@...e.com>,
        "linux-block@...r.kernel.org" <linux-block@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "nborisov@...e.com" <nborisov@...e.com>,
        "oleg.b.antonyan@...il.com" <oleg.b.antonyan@...il.com>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-xfs@...r.kernel.org" <linux-xfs@...r.kernel.org>,
        "pavel@....cz" <pavel@....cz>,
        "darrick.wong@...cle.com" <darrick.wong@...cle.com>,
        "viro@...iv.linux.org.uk" <viro@...iv.linux.org.uk>,
        "ming.lei@...hat.com" <ming.lei@...hat.com>,
        "jgross@...e.com" <jgross@...e.com>,
        "oleksandr@...alenko.name" <oleksandr@...alenko.name>,
        "todd.e.brandt@...ux.intel.com" <todd.e.brandt@...ux.intel.com>,
        "martin.petersen@...cle.com" <martin.petersen@...cle.com>,
        "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
        "jikos@...nel.org" <jikos@...nel.org>,
        "len.brown@...el.com" <len.brown@...el.com>,
        "tytso@....edu" <tytso@....edu>, "jack@...e.cz" <jack@...e.cz>
Subject: Re: [RFC 5/5] pm: remove kernel thread freezing

On Wed, 2017-10-04 at 02:47 +0200, Luis R. Rodriguez wrote:
>   3) Lookup for kthreads which seem to generate IO -- address / review if
>      removal of the freezer API can be done somehow with a quescing. This
>      is currently for example being done on SCSI / md.
>  4) Only after all the above is done should we consider this patch or some
>     form of it.

After having given this more thought, I think we should omit these last two
steps. Modifying the md driver such that it does not submit I/O requests while
processes are frozen requires either to use the freezer API or to open-code it.
I think there is general agreement in the kernel community that open-coding a
single mechanism in multiple drivers is wrong. Does this mean that instead of
removing the freezer API we should keep it and review all its users instead?

Bart.