linux-kernel - Re: [PATCH] drm/qxl: Call qxl_bo

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Message-ID: <20180604073723.ld7b2h5veqsxoun6@sirius.home.kraxel.org>
Date:   Mon, 4 Jun 2018 09:37:23 +0200
From:   Gerd Hoffmann <kraxel@...hat.com>
To:     Jeremy Cline <jcline@...hat.com>
Cc:     Dave Airlie <airlied@...hat.com>, Ray Strode <rstrode@...hat.com>,
        virtualization@...ts.linux-foundation.org,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org
Subject: Re: [PATCH] drm/qxl: Call qxl_bo_unref outside atomic context

On Fri, Jun 01, 2018 at 04:05:32PM -0400, Jeremy Cline wrote:
> "qxl_bo_unref" may sleep, but calling "qxl_release_map" causes
> "preempt_disable()" to be called and "preempt_enable()" isn't called
> until "qxl_release_unmap" is used. Move the call to "qxl_bo_unref" out
> from in between the two to avoid sleeping from an atomic context.
> 
> This issue can be demonstrated on a kernel with CONFIG_LOCKDEP=y by
> creating a VM using QXL, using a desktop environment using Xorg, then
> moving the cursor on or off a window.
> 
> Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1571128
> Fixes: 9428088c90b6 ("drm/qxl: reapply cursor after resetting primary")
> Cc: stable@...r.kernel.org
> Signed-off-by: Jeremy Cline <jcline@...hat.com>

Pushed to drm-misc-fixes.

thanks,
  Gerd