Re: [PATCH stable 4.12 - 4.19] driver core: Postpone DMA tear-down until after devres release for probe failure

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Wed, May 22, 2019 at 06:45:41PM +0800, John Garry wrote:
> commit 0b777eee88d712256ba8232a9429edb17c4f9ceb upstream
> 
> 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.
> 
> 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>
> Cc: stable <stable@vger.kernel.org> # 4.12.x - 4.19.x
> Reviewed-by: Robin Murphy <robin.murphy@arm.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> [jpg: backport to 4.19.x and earlier]
> Signed-off-by: John Garry <john.garry@huawei.com>

Now queued up everywhere, thanks for the backport.

greg k-h