linux-kernel - Issue with DRM and "reimplement IDR and IDA using the radix tree"

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-next>] [day] [month] [year] [list]

Message-ID: <fd3db206-8b3e-150f-a060-e88cc2f49606@nvidia.com>
Date:   Tue, 13 Dec 2016 16:14:00 +0900
From:   Alexandre Courbot <acourbot@...dia.com>
To:     Matthew Wilcox <willy@...ux.intel.com>
CC:     Andrew Morton <akpm@...ux-foundation.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>
Subject: Issue with DRM and "reimplement IDR and IDA using the radix tree"

Hi Matthew,

Trying the latest -next on the Jetson TK1 board (with two different DRM
devices and display and render), I noticed that the GPU device probe
always failed with error -ENOSPC. After investigating I figured out that
this was due to the minor device allocation failing when a second DRM
device is added.

More precisely, when drm_minor_alloc() is called with DRM_MINOR_PRIMARY
(0) as argument for a second time, the call to idr_alloc() (which has a
requested range of 0..64) fails instead of returning 1 as expected. Note
that the first call is successful.

Reverting "reimplement IDR and IDA using the radix tree" on 20161213's
next fixes the issue for me, suggesting a bug may have slipped in there.

Not sure how this could be fixed, so reporting the issue for now in case
it is not known yet.

Cheers,
Alex.