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SubjectRe: [PATCH] driver core: Postpone DMA tear-down until after devres release for probe failure
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On 03/04/2019 09:14, Greg KH wrote:
> On Wed, Apr 03, 2019 at 09:02:36AM +0100, John Garry wrote:
>> On 28/03/2019 10:08, John Garry wrote:
>>> In commit 376991db4b64 ("driver core: Postpone DMA tear-down until after
>>> devres release"), we changed the ordering of tearing down the device DMA
>>> ops and releasing all the device's resources; this was because the DMA ops
>>> should be maintained until we release the device's managed DMA memories.
>>>
>>
>> Hi all,
>>
>> A friendly reminder on this patch... I didn't see any update.
>>
>> I thought that it had some importance.
>>
>> Thanks,
>> John
>>
>>> However, we have seen another crash on an arm64 system when a
>>> device driver probe fails:
>>>
>>> hisi_sas_v3_hw 0000:74:02.0: Adding to iommu group 2
>>> scsi host1: hisi_sas_v3_hw
>>> BUG: Bad page state in process swapper/0 pfn:313f5
>>> page:ffff7e0000c4fd40 count:1 mapcount:0
>>> mapping:0000000000000000 index:0x0
>>> flags: 0xfffe00000001000(reserved)
>>> raw: 0fffe00000001000 ffff7e0000c4fd48 ffff7e0000c4fd48
>>> 0000000000000000
>>> raw: 0000000000000000 0000000000000000 00000001ffffffff
>>> 0000000000000000
>>> page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
>>> bad because of flags: 0x1000(reserved)
>>> Modules linked in:
>>> CPU: 49 PID: 1 Comm: swapper/0 Not tainted
>>> 5.1.0-rc1-43081-g22d97fd-dirty #1433
>>> Hardware name: Huawei D06/D06, BIOS Hisilicon D06 UEFI
>>> RC0 - V1.12.01 01/29/2019
>>> Call trace:
>>> dump_backtrace+0x0/0x118
>>> show_stack+0x14/0x1c
>>> dump_stack+0xa4/0xc8
>>> bad_page+0xe4/0x13c
>>> free_pages_check_bad+0x4c/0xc0
>>> __free_pages_ok+0x30c/0x340
>>> __free_pages+0x30/0x44
>>> __dma_direct_free_pages+0x30/0x38
>>> dma_direct_free+0x24/0x38
>>> dma_free_attrs+0x9c/0xd8
>>> dmam_release+0x20/0x28
>>> release_nodes+0x17c/0x220
>>> devres_release_all+0x34/0x54
>>> really_probe+0xc4/0x2c8
>>> driver_probe_device+0x58/0xfc
>>> device_driver_attach+0x68/0x70
>>> __driver_attach+0x94/0xdc
>>> bus_for_each_dev+0x5c/0xb4
>>> driver_attach+0x20/0x28
>>> bus_add_driver+0x14c/0x200
>>> driver_register+0x6c/0x124
>>> __pci_register_driver+0x48/0x50
>>> sas_v3_pci_driver_init+0x20/0x28
>>> do_one_initcall+0x40/0x25c
>>> kernel_init_freeable+0x2b8/0x3c0
>>> kernel_init+0x10/0x100
>>> ret_from_fork+0x10/0x18
>>> Disabling lock debugging due to kernel taint
>>> BUG: Bad page state in process swapper/0 pfn:313f6
>>> page:ffff7e0000c4fd80 count:1 mapcount:0
>>> mapping:0000000000000000 index:0x0
>>> [ 89.322983] flags: 0xfffe00000001000(reserved)
>>> raw: 0fffe00000001000 ffff7e0000c4fd88 ffff7e0000c4fd88
>>> 0000000000000000
>>> raw: 0000000000000000 0000000000000000 00000001ffffffff
>>> 0000000000000000
>>>
>>> The crash occurs for the same reason.
>>>
>>> In this case, on the really_probe() failure path, we are still clearing
>>> the DMA ops prior to releasing the device's managed memories.
>>>
>>> This patch fixes this issue by reordering the DMA ops teardown and the
>>> call to devres_release_all() on the failure path.
>>>
>>> Reported-by: Xiang Chen <chenxiang66@hisilicon.com>
>>> Tested-by: Xiang Chen <chenxiang66@hisilicon.com>
>>> Signed-off-by: John Garry <john.garry@huawei.com>
>
> So does this "fix" 376991db4b64? If so, should this be added to the
> patch and also backported to the stable trees?

Hi Greg,

No, I don't think so. I'd say it supplements it. Here I'm trying to fix
up another path in which we tear down the DMA ops prior to releasing the
device's resources.

I didn't add a fixes tag as 376991db4b64 didn't have one either. It will
need to be backported to stable, I figure the same as 376991db4b64.

Thanks,
John

>
> thanks,
>
> greg k-h
>
> .
>


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