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Date: Mon, 7 Mar 2016 12:46:54 -0800
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: andersen@codepoet.org, linux-kernel <linux-kernel@vger.kernel.org>,
        Nicolai =?iso-8859-1?Q?H=E4hnle?= <nicolai.haehnle@amd.com>,
        Christian =?iso-8859-1?Q?K=F6nig?= <christian.koenig@amd.com>
Cc: stable@vger.kernel.org
Subject: Re: Oops in 3.10.99 -- NULL pointer dereference in radeon_fence_ref
Message-ID: <20160307204654.GB6545@kroah.com>
References: <20160307025014.GA9499@mail.codepoet.org>
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On Sun, Mar 06, 2016 at 07:50:14PM -0700, Erik Andersen wrote:
> The following patch to radeon_sa_bo_new that
> went into 3.10.99
> 
>   commit 8d5e1e5af0c667545c202e8f4051f77aa3bf31b7
>   Author: Nicolai Hähnle <nicolai.haehnle@amd.com>
>   Date:   Fri Feb 5 14:35:53 2016 -0500
>     drm/radeon: hold reference to fences in radeon_sa_bo_new
>     commit f6ff4f67cdf8455d0a4226eeeaf5af17c37d05eb upstream.
> 
> is triggering an Oops for me right when xscreensaver
> first began doing 3D stuff.  After reverting this
> patch, xscreensaver has been happily running 3D stuff.
> 
> Mar  6 18:00:43 sage kernel: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
> Mar  6 18:00:43 sage kernel: IP: [<ffffffffa010345d>] radeon_fence_ref+0xd/0x50 [radeon]
> Mar  6 18:00:43 sage kernel: PGD 799e1d067 PUD 819186067 PMD 0
> Mar  6 18:00:43 sage kernel: Oops: 0002 [#1] SMP
> 
> Mar  6 18:00:43 sage kernel: Stack:
> Mar  6 18:00:43 sage kernel:  ffffffffa01607ec ffff88108a4e8000 ffff88108a4e8000 ffff880888fbc000
> Mar  6 18:00:43 sage kernel:  ffff880ecbf11c78 0000fe2001000006 0000000000000000 0020000000000100
> Mar  6 18:00:43 sage kernel:  00000000000d1200 ffff880ecbf11c14 0000000000000000 0000000000000000
> Mar  6 18:00:43 sage kernel: Call Trace:
> Mar  6 18:00:43 sage kernel:  [<ffffffffa01607ec>] ? radeon_sa_bo_new+0x2ac/0x4f0 [radeon]
> Mar  6 18:00:43 sage kernel:  [<ffffffffa005fc9d>] ? ttm_eu_list_ref_sub+0x3d/0x60 [ttm]
> Mar  6 18:00:43 sage kernel:  [<ffffffffa0117c49>] radeon_ib_get+0x39/0x110 [radeon]
> Mar  6 18:00:43 sage kernel:  [<ffffffffa011a4ea>] radeon_cs_ioctl+0x69a/0xa70 [radeon]
> Mar  6 18:00:43 sage kernel:  [<ffffffffa008e2d2>] drm_ioctl+0x512/0x650 [drm]
> Mar  6 18:00:43 sage kernel:  [<ffffffff810a46e1>] ? do_futex+0x111/0xc30
> Mar  6 18:00:43 sage kernel:  [<ffffffff81182a45>] do_vfs_ioctl+0x305/0x520
> Mar  6 18:00:43 sage kernel:  [<ffffffff8107cd39>] ? vtime_account_user+0x69/0x80
> Mar  6 18:00:43 sage kernel:  [<ffffffff81182ce1>] SyS_ioctl+0x81/0xa0
> Mar  6 18:00:43 sage kernel:  [<ffffffff8178210f>] tracesys+0xe1/0xe6
> 
> $ lspci | grep VGA
> 03:00.0 VGA compatible controller: Advanced Micro Devices, Inc.
> [AMD/ATI] Redwood XT [Radeon HD 5670/5690/5730]

Next time, please cc: the people responsible for that patch as well...

I can revert it, but maybe something else is going on here?  Do you have
this same problem on 3.14, and 4.5-rc7?

thanks,

greg k-h