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Date: Mon, 08 Nov 2010 23:29:16 +0100
From: Thomas Hellstrom <thellstrom@vmware.com>
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To: Jerome Glisse <j.glisse@gmail.com>
CC: Markus Trippelsdorf <markus@trippelsdorf.de>,
        "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "airlied@linux.ie" <airlied@linux.ie>
Subject: Re: Radeon RS780 - BUG: unable to handle kernel NULL pointer dereference
References: <20101108170221.GA1602@arch.trippelsdorf.de>	<20101108170737.GA1617@arch.trippelsdorf.de>	<20101108184301.GA1614@arch.trippelsdorf.de>	<20101108190258.GA1623@arch.trippelsdorf.de> <AANLkTi=fo3rnBp8Fs6H+ivP6R+x=QDzBLyi+DmT-LNHV@mail.gmail.com>
In-Reply-To: <AANLkTi=fo3rnBp8Fs6H+ivP6R+x=QDzBLyi+DmT-LNHV@mail.gmail.com>
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On 11/08/2010 09:53 PM, Jerome Glisse wrote:
> On Mon, Nov 8, 2010 at 2:02 PM, Markus Trippelsdorf
> <markus@trippelsdorf.de>  wrote:
>    
>> On Mon, Nov 08, 2010 at 07:43:02PM +0100, Markus Trippelsdorf wrote:
>>      
>>> On Mon, Nov 08, 2010 at 06:07:37PM +0100, Markus Trippelsdorf wrote:
>>>        
>>>> On Mon, Nov 08, 2010 at 06:02:21PM +0100, Markus Trippelsdorf wrote:
>>>>          
>>>>> I can trigger a kernel crash on my system by simply loading this png
>>>>> image with firefox:
>>>>> http://mediaarchive.cern.ch/MediaArchive/Photo/Public/2010/1011251/1011251_01/1011251_01-A4-at-144-dpi.jpg
>>>>>            
>>>> Sorry the above link is wrong, this is the right one (that triggers the
>>>> crash):
>>>> http://cdsweb.cern.ch/record/1305179/files/HI-150431-630470-huge.png
>>>>          
>>> I triggered it a few more times and took the attached picture.
>>> It points to the BUG() call at drivers/gpu/drm/ttm/ttm_bo.c:1628 .
>>> (Sorry for the bad picture quality)
>>>        
>> And here the same BUG in plaintext (should be a bit easier to read):
>>
>> Nov  8 19:28:23 arch kernel: ------------[ cut here ]------------
>> Nov  8 19:28:23 arch kernel: kernel BUG at drivers/gpu/drm/ttm/ttm_bo.c:1628!
>> Nov  8 19:28:23 arch kernel: invalid opcode: 0000 [#1] PREEMPT SMP
>> Nov  8 19:28:23 arch kernel: last sysfs file: /sys/devices/pci0000:00/0000:00:18.3/temp1_input
>> Nov  8 19:28:23 arch kernel: CPU 1
>> Nov  8 19:28:23 arch kernel: Pid: 1541, comm: X Not tainted 2.6.37-rc1-00116-g151f52f-dirty #31 M4A78T-E/System Product Name
>> Nov  8 19:28:23 arch kernel: RIP: 0010:[<ffffffff8121f0ff>]  [<ffffffff8121f0ff>] ttm_bo_init+0x30f/0x340
>> Nov  8 19:28:23 arch kernel: RSP: 0018:ffff88011b0fbbe8  EFLAGS: 00010246
>> Nov  8 19:28:23 arch kernel: RAX: ffff8800da881778 RBX: ffff8800da881620 RCX: ffff88011b15ed78
>> Nov  8 19:28:23 arch kernel: RDX: ffff8800c1556040 RSI: ffff88011ff22770 RDI: 000000000017adfb
>> Nov  8 19:28:23 arch kernel: RBP: ffff8800da881648 R08: 0000000000000000 R09: ffff8800c1556040
>> Nov  8 19:28:23 arch kernel: R10: 000000000ff85205 R11: ffff8800dae19200 R12: 0000000000000001
>> Nov  8 19:28:23 arch kernel: R13: ffff88011ff22528 R14: ffff88011ff22778 R15: 0000000000000000
>> Nov  8 19:28:23 arch kernel: FS:  00007f2043043700(0000) GS:ffff8800dfc80000(0000) knlGS:0000000000000000
>> Nov  8 19:28:23 arch kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> Nov  8 19:28:23 arch kernel: CR2: 00007f203d057000 CR3: 000000011b12b000 CR4: 00000000000006e0
>> Nov  8 19:28:23 arch kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> Nov  8 19:28:23 arch kernel: DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
>> Nov  8 19:28:23 arch kernel: Process X (pid: 1541, threadinfo ffff88011b0fa000, task ffff88011c959c20)
>> Nov  8 19:28:23 arch kernel: Stack:
>> Nov  8 19:28:23 arch kernel: 0000000000000000 ffff8800da881648 ffff88011b0fbd00 ffff8800da881600
>> Nov  8 19:28:23 arch kernel: ffff88011ff22000 0000000000000000 0000000000000001 00000000fffffff4
>> Nov  8 19:28:23 arch kernel: ffff88011b0fbd00 ffffffff8125294d 0000000000000000 ffffffff00000001
>> Nov  8 19:28:23 arch kernel: Call Trace:
>> Nov  8 19:28:23 arch kernel: [<ffffffff8125294d>] ? radeon_bo_create+0x14d/0x250
>> Nov  8 19:28:23 arch kernel: [<ffffffff812526c0>] ? radeon_ttm_bo_destroy+0x0/0xb0
>> Nov  8 19:28:23 arch kernel: [<ffffffff812671cc>] ? radeon_gem_object_create+0x8c/0x130
>> Nov  8 19:28:23 arch kernel: [<ffffffff81267634>] ? radeon_gem_create_ioctl+0x54/0xd0
>> Nov  8 19:28:23 arch kernel: [<ffffffff813ab26d>] ? sock_aio_read+0x10d/0x120
>> Nov  8 19:28:23 arch kernel: [<ffffffff8120963c>] ? drm_ioctl+0x39c/0x450
>> Nov  8 19:28:23 arch kernel: [<ffffffff812675e0>] ? radeon_gem_create_ioctl+0x0/0xd0
>> Nov  8 19:28:23 arch kernel: [<ffffffff810dd2c9>] ? do_vfs_ioctl+0xa9/0x610
>> Nov  8 19:28:23 arch kernel: [<ffffffff810dd879>] ? sys_ioctl+0x49/0x80
>> Nov  8 19:28:23 arch kernel: [<ffffffff810ce24e>] ? sys_read+0x4e/0x90
>> Nov  8 19:28:23 arch kernel: [<ffffffff8102dc2b>] ? system_call_fastpath+0x16/0x1b
>> Nov  8 19:28:23 arch kernel: Code: e8 fb ff ff 85 c0 0f 85 68 ff ff ff 48 8b 7c 24 08 89 04 24 e8 83 d9 ff ff 8b 04 24 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f c3<0f>  0b 48 c7 c7 60 a4 55 81 31 c0 e8 14 80 22 00 b8 ea ff ff ff
>> Nov  8 19:28:23 arch kernel: RIP  [<ffffffff8121f0ff>] ttm_bo_init+0x30f/0x340
>> Nov  8 19:28:23 arch kernel: RSP<ffff88011b0fbbe8>
>> Nov  8 19:28:23 arch kernel: ---[ end trace 328a9acba7691d6e ]---
>> Nov  8 19:28:23 arch kernel: note: X[1541] exited with preempt_count 1
>> Nov  8 19:28:23 arch kernel: BUG: scheduling while atomic: X/1541/0x10000002
>> Nov  8 19:28:23 arch kernel: Pid: 1541, comm: X Tainted: G      D     2.6.37-rc1-00116-g151f52f-dirty #31
>> Nov  8 19:28:23 arch kernel: Call Trace:
>> Nov  8 19:28:23 arch kernel: [<ffffffff81447ad9>] ? schedule+0x639/0x850
>> Nov  8 19:28:23 arch kernel: [<ffffffff8105826d>] ? __cond_resched+0x1d/0x30
>> Nov  8 19:28:23 arch kernel: [<ffffffff81447f2f>] ? _cond_resched+0x2f/0x40
>> Nov  8 19:28:23 arch kernel: [<ffffffff810b57fc>] ? unmap_vmas+0x82c/0x9c0
>> Nov  8 19:28:23 arch kernel: [<ffffffff810bcb62>] ? exit_mmap+0xe2/0x1a0
>> Nov  8 19:28:23 arch kernel: [<ffffffff8105a705>] ? mmput+0x25/0xc0
>> Nov  8 19:28:23 arch kernel: [<ffffffff8105e734>] ? exit_mm+0x104/0x130
>> Nov  8 19:28:23 arch kernel: [<ffffffff81079ebf>] ? hrtimer_try_to_cancel+0x3f/0x80
>> Nov  8 19:28:23 arch kernel: [<ffffffff81089d0a>] ? acct_collect+0x9a/0x1a0
>> Nov  8 19:28:23 arch kernel: [<ffffffff8106045a>] ? do_exit+0x5aa/0x760
>> Nov  8 19:28:23 arch kernel: [<ffffffff81447163>] ? printk+0x40/0x45
>> Nov  8 19:28:23 arch kernel: [<ffffffff8105e33c>] ? kmsg_dump+0x7c/0x150
>> Nov  8 19:28:23 arch kernel: [<ffffffff81031fda>] ? oops_end+0x9a/0xe0
>> Nov  8 19:28:23 arch kernel: [<ffffffff8102ee74>] ? do_invalid_op+0x84/0xa0
>> Nov  8 19:28:23 arch kernel: [<ffffffff8121f0ff>] ? ttm_bo_init+0x30f/0x340
>> Nov  8 19:28:23 arch kernel: [<ffffffff810ddf50>] ? __pollwait+0x0/0x110
>> Nov  8 19:28:23 arch kernel: [<ffffffff8102e7d5>] ? invalid_op+0x15/0x20
>> Nov  8 19:28:23 arch kernel: [<ffffffff8121f0ff>] ? ttm_bo_init+0x30f/0x340
>> Nov  8 19:28:23 arch kernel: [<ffffffff8121efe3>] ? ttm_bo_init+0x1f3/0x340
>> Nov  8 19:28:23 arch kernel: [<ffffffff8125294d>] ? radeon_bo_create+0x14d/0x250
>> Nov  8 19:28:23 arch kernel: [<ffffffff812526c0>] ? radeon_ttm_bo_destroy+0x0/0xb0
>> Nov  8 19:28:23 arch kernel: [<ffffffff812671cc>] ? radeon_gem_object_create+0x8c/0x130
>> Nov  8 19:28:23 arch kernel: [<ffffffff81267634>] ? radeon_gem_create_ioctl+0x54/0xd0
>> Nov  8 19:28:23 arch kernel: [<ffffffff813ab26d>] ? sock_aio_read+0x10d/0x120
>> Nov  8 19:28:23 arch kernel: [<ffffffff8120963c>] ? drm_ioctl+0x39c/0x450
>> Nov  8 19:28:23 arch kernel: [<ffffffff812675e0>] ? radeon_gem_create_ioctl+0x0/0xd0
>> Nov  8 19:28:23 arch kernel: [<ffffffff810dd2c9>] ? do_vfs_ioctl+0xa9/0x610
>> Nov  8 19:28:23 arch kernel: [<ffffffff810dd879>] ? sys_ioctl+0x49/0x80
>> Nov  8 19:28:23 arch kernel: [<ffffffff810ce24e>] ? sys_read+0x4e/0x90
>> Nov  8 19:28:23 arch kernel: [<ffffffff8102dc2b>] ? system_call_fastpath+0x16/0x1b
>> Nov  8 19:28:23 arch kernel: BUG: scheduling while atomic: X/1541/0x10000002
>> Nov  8 19:28:23 arch kernel: Pid: 1541, comm: X Tainted: G      D     2.6.37-rc1-00116-g151f52f-dirty #31
>> Nov  8 19:28:23 arch kernel: Call Trace:
>> Nov  8 19:28:23 arch kernel: [<ffffffff81447ad9>] ? schedule+0x639/0x850
>> Nov  8 19:28:23 arch kernel: [<ffffffff8105826d>] ? __cond_resched+0x1d/0x30
>> Nov  8 19:28:23 arch kernel: [<ffffffff81447f2f>] ? _cond_resched+0x2f/0x40
>> Nov  8 19:28:23 arch kernel: [<ffffffff810b57fc>] ? unmap_vmas+0x82c/0x9c0
>> Nov  8 19:28:23 arch kernel: [<ffffffff810bcb62>] ? exit_mmap+0xe2/0x1a0
>> Nov  8 19:28:23 arch kernel: [<ffffffff8105a705>] ? mmput+0x25/0xc0
>> Nov  8 19:28:23 arch kernel: [<ffffffff8105e734>] ? exit_mm+0x104/0x130
>> Nov  8 19:28:23 arch kernel: [<ffffffff81079ebf>] ? hrtimer_try_to_cancel+0x3f/0x80
>> Nov  8 19:28:23 arch kernel: [<ffffffff81089d0a>] ? acct_collect+0x9a/0x1a0
>> Nov  8 19:28:23 arch kernel: [<ffffffff8106045a>] ? do_exit+0x5aa/0x760
>> Nov  8 19:28:23 arch kernel: [<ffffffff81447163>] ? printk+0x40/0x45
>> Nov  8 19:28:23 arch kernel: [<ffffffff8105e33c>] ? kmsg_dump+0x7c/0x150
>> Nov  8 19:28:23 arch kernel: [<ffffffff81031fda>] ? oops_end+0x9a/0xe0
>> Nov  8 19:28:23 arch kernel: [<ffffffff8102ee74>] ? do_invalid_op+0x84/0xa0
>> Nov  8 19:28:23 arch kernel: [<ffffffff8121f0ff>] ? ttm_bo_init+0x30f/0x340
>> Nov  8 19:28:23 arch kernel: [<ffffffff810ddf50>] ? __pollwait+0x0/0x110
>> Nov  8 19:28:23 arch kernel: [<ffffffff8102e7d5>] ? invalid_op+0x15/0x20
>> Nov  8 19:28:23 arch kernel: [<ffffffff8121f0ff>] ? ttm_bo_init+0x30f/0x340
>> Nov  8 19:28:23 arch kernel: [<ffffffff8121efe3>] ? ttm_bo_init+0x1f3/0x340
>> Nov  8 19:28:23 arch kernel: [<ffffffff8125294d>] ? radeon_bo_create+0x14d/0x250
>> Nov  8 19:28:23 arch kernel: [<ffffffff812526c0>] ? radeon_ttm_bo_destroy+0x0/0xb0
>> Nov  8 19:28:23 arch kernel: [<ffffffff812671cc>] ? radeon_gem_object_create+0x8c/0x130
>> Nov  8 19:28:23 arch kernel: [<ffffffff81267634>] ? radeon_gem_create_ioctl+0x54/0xd0
>> Nov  8 19:28:23 arch kernel: [<ffffffff813ab26d>] ? sock_aio_read+0x10d/0x120
>> Nov  8 19:28:23 arch kernel: [<ffffffff8120963c>] ? drm_ioctl+0x39c/0x450
>> Nov  8 19:28:23 arch kernel: [<ffffffff812675e0>] ? radeon_gem_create_ioctl+0x0/0xd0
>> Nov  8 19:28:23 arch kernel: [<ffffffff810dd2c9>] ? do_vfs_ioctl+0xa9/0x610
>> Nov  8 19:28:23 arch kernel: [<ffffffff810dd879>] ? sys_ioctl+0x49/0x80
>> Nov  8 19:28:23 arch kernel: [<ffffffff810ce24e>] ? sys_read+0x4e/0x90
>> Nov  8 19:28:23 arch kernel: [<ffffffff8102dc2b>] ? system_call_fastpath+0x16/0x1b
>>
>>      
> Thomas this bug seems to point to a case where we endup trying adding
> an entry to
> same offset in the rb tree for addr_space_mm. After reviewing
> carefully the locking
> around the rb tree modification&  addr_space_mm i am fairly confident
> that no race can
> occur. Would you have any idea on what might go wrong here ? I guess i would
> ultimately need to dump mm&  rb tree state when BUG get trigger to try
> to understand
> states of things.
>
> Cheers,
> Jerome
>    

I agree there shouldn't be a race in this case.
The locking around these operations is simple and straightforward.

So this IMHO should either be a memory corruption or a bug in the range 
manager. I've never seen this BUG trigger before. Dumping mm / rb tree 
contents or bisecting should probably find the culprit.

/Thomas




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