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Message-ID: <188afd4d2e299652da33ad5d4ea743f02fb2ffc5.camel@pengutronix.de>
Subject: Re: [PATCH] kernel: Expose SYS_kcmp by default
From:   Lucas Stach <l.stach@pengutronix.de>
To:     Pavel Machek <pavel@ucw.cz>,
        Chris Wilson <chris@chris-wilson.co.uk>
Cc:     linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        intel-gfx@lists.freedesktop.org, Kees Cook <keescook@chromium.org>,
        Andy Lutomirski <luto@amacapital.net>,
        Will Drewry <wad@chromium.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Dave Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>
Date:   Mon, 15 Feb 2021 11:23:11 +0100
In-Reply-To: <20210213174000.GA31409@duo.ucw.cz>
References: <20210205163752.11932-1-chris@chris-wilson.co.uk>
         <20210213174000.GA31409@duo.ucw.cz>
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Am Samstag, dem 13.02.2021 um 18:40 +0100 schrieb Pavel Machek:
> Hi!
> 
> > Userspace has discovered the functionality offered by SYS_kcmp and has
> > started to depend upon it. In particular, Mesa uses SYS_kcmp for
> > os_same_file_description() in order to identify when two fd (e.g. device
> > or dmabuf) point to the same struct file. Since they depend on it for
> > core functionality, lift SYS_kcmp out of the non-default
> > CONFIG_CHECKPOINT_RESTORE into the selectable syscall category.
> 
> Is it good idea to enable everything because Mesa uses it for file
> descriptors?
> 
> This is really interesting syscall...

As Debian/Ubuntu and Fedora are already shipping with
CONFIG_CHECKPOINT_RESTORE=y in their kernel configs, I don't really see
the need to add further restrictions here. Or this discussion should
have happened a while ago...

Regards,
Lucas