Re: [PATCH/RFC] driver core: Postpone DMA tear-down until after devres release

[John Garry <john.garry@huawei.com>]

On 11/02/2019 10:22, Robin Murphy wrote:
> On 08/02/2019 18:55, Geert Uytterhoeven wrote:
>> Hi Robin,
>>
>> On Fri, Feb 8, 2019 at 6:55 PM Robin Murphy <robin.murphy@arm.com> wrote:
>>> On 08/02/2019 16:40, Joerg Roedel wrote:
>>>> On Thu, Feb 07, 2019 at 08:36:53PM +0100, Geert Uytterhoeven wrote:
>>>>> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
>>>>> index 8ac10af17c0043a3..d62487d024559620 100644
>>>>> --- a/drivers/base/dd.c
>>>>> +++ b/drivers/base/dd.c
>>>>> @@ -968,9 +968,9 @@ static void __device_release_driver(struct
>>>>> device *dev, struct device *parent)
>>>>>                       drv->remove(dev);
>>>>>
>>>>>               device_links_driver_cleanup(dev);
>>>>> -            arch_teardown_dma_ops(dev);
>>>>>
>>>>>               devres_release_all(dev);
>>>>> +            arch_teardown_dma_ops(dev);
>>>>>               dev->driver = NULL;
>>>>>               dev_set_drvdata(dev, NULL);
>>>>>               if (dev->pm_domain && dev->pm_domain->dismiss)
>>>>
>>>> Thanks for the fix! Should it also be tagged for stable and get a Fixes
>>
>> FTR, Greg has added it to driver-core-testing, with a CC to stable.
>
> So I see, great!
>
>>>> tag? I know it only triggers with a fix in v5.0-rc, but still...
>>>
>>> I think so:
>>>
>>> Fixes: 09515ef5ddad ("of/acpi: Configure dma operations at probe time
>>> for platform/amba/pci bus devices")
>>
>> Thanks! It won't backport cleanly due to commit dc3c05504d38849f
>> ("dma-mapping: remove dma_deconfigure") in v4.20, though.
>
> Ah yes - backports beyond that should simply be a case of moving the
> dma_deconfigure() wrapper in the same manner.
>

Hi guys,

Any idea what happened to this fix?

I have this on 5.0:

[    0.000000] Linux version 5.0.0 (john@htsatcamb-server) (gcc version 
4.8.5 (Linaro GCC 4.8-2015.06)) #121 SMP PREEMPT Thu Mar 7 14:28:39 GMT 2019
[    0.000000] Kernel command line: BOOT_IMAGE=/john/Image rdinit=/init 
crashkernel=256M@32M earlycon console=ttyAMA0,115200 acpi=force 
pcie_aspm=off scsi_mod.use_blk_mq=y no_console_suspend pcie-hisi.disable=1

...

[   26.806856] pci_bus 000c:20: 2-byte config write to 000c:20:00.0 
offset 0x44 may corrupt adjacent RW1C bits
[   26.817521] pcieport 0002:f8:00.0: can't derive routing for PCI INT B
[   26.837167] pci_bus 000c:20: 2-byte config write to 000c:20:00.0 
offset 0x44 may corrupt adjacent RW1C bits
[   26.850091] serial 0002:f9:00.1: PCI INT B: no GSI
[   26.879364] serial 0002:f9:00.1: enabling device (0000 -> 0003)
[   26.913131] 0002:f9:00.1: ttyS3 at I/O 0x1008 (irq = 0, base_baud = 
115200) is a ST16650V2
[   26.992897] rtc-efi rtc-efi: setting system clock to 
2019-03-07T14:41:48 UTC (1551969708)
[   27.009380] ALSA device list:
[   27.015326]   No soundcards found.
[   27.022549] Freeing unused kernel memory: 1216K
[   27.055567] Run /init as init process
root@(none)$ cd /sys/devices/platform/HISI0162:01
root@(none)$ echo HISI0162:01 > driver/unbind
[   36.488040] hisi_sas_v2_hw HISI0162:01: dev[9:1] is gone
[   36.561077] hisi_sas_v2_hw HISI0162:01: dev[8:1] is gone
[   36.621061] hisi_sas_v2_hw HISI0162:01: dev[7:1] is gone
[   36.693074] hisi_sas_v2_hw HISI0162:01: dev[6:1] is gone
[   36.753066] hisi_sas_v2_hw HISI0162:01: dev[5:1] is gone
[   36.764276] sd 0:0:3:0: [sdd] Synchronizing SCSI cache
[   36.821106] hisi_sas_v2_hw HISI0162:01: dev[4:1] is gone
[   36.889048] hisi_sas_v2_hw HISI0162:01: dev[3:1] is gone
[   36.993002] hisi_sas_v2_hw HISI0162:01: dev[1:1] is gone
[   37.004276] sd 0:0:0:0: [sda] Synchronizing SCSI cache
[   37.014768] sd 0:0:0:0: [sda] Stopping disk
[   37.709094] hisi_sas_v2_hw HISI0162:01: dev[2:5] is gone
[   37.721231] hisi_sas_v2_hw HISI0162:01: dev[0:2] is gone
[   37.803774] BUG: Bad page state in process sh  pfn:11356
[   37.814444] page:ffff7e000044d580 count:1 mapcount:0 
mapping:0000000000000000 index:0x0
[   37.830525] flags: 0xfffc00000001000(reserved)
[   37.839443] raw: 0fffc00000001000 ffff7e000044d588 ffff7e000044d588 
0000000000000000
[   37.854998] raw: 0000000000000000 0000000000000000 00000001ffffffff 
0000000000000000
[   37.870552] page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
[   37.883485] bad because of flags: 0x1000(reserved)
[   37.893098] Modules linked in:
[   37.899221] CPU: 5 PID: 2691 Comm: sh Not tainted 5.0.0 #121
[   37.910578] Hardware name: Huawei Taishan 2280 /D05, BIOS Hisilicon 
D05 IT21 Nemo 2.0 RC0 04/18/2018
[   37.928924] Call trace:
[   37.933825]  dump_backtrace+0x0/0x150
[   37.941166]  show_stack+0x14/0x1c
[   37.947808]  dump_stack+0x8c/0xb0
[   37.954451]  bad_page+0xe4/0x144
[   37.960918]  free_pages_check_bad+0x7c/0x84
[   37.969307]  __free_pages_ok+0x284/0x290
[   37.977173]  __free_pages+0x30/0x44
[   37.984163]  __dma_direct_free_pages+0x68/0x6c
[   37.993076]  dma_direct_free+0x24/0x38
[   38.000591]  dma_free_attrs+0x84/0xc0
[   38.007930]  dmam_release+0x20/0x28
[   38.014924]  release_nodes+0x128/0x1f8
[   38.022439]  devres_release_all+0x34/0x4c
[   38.030478]  device_release_driver_internal+0x190/0x208
[   38.040963]  device_release_driver+0x14/0x1c
[   38.049526]  unbind_store+0xbc/0xf4
[   38.056517]  drv_attr_store+0x20/0x30
[   38.063859]  sysfs_kf_write+0x44/0x4c
[   38.071200]  kernfs_fop_write+0xd0/0x1c4
[   38.079065]  __vfs_write+0x2c/0x158
[   38.086055]  vfs_write+0xa8/0x19c
[   38.092696]  ksys_write+0x44/0xa0
[   38.099338]  __arm64_sys_write+0x1c/0x24
[   38.107203]  el0_svc_common+0xb0/0x100
[   38.114718]  el0_svc_handler+0x70/0x88
[   38.122232]  el0_svc+0x8/0x7c0
[   38.128356] Disabling lock debugging due to kernel taint
[   38.139019] BUG: Bad page state in process sh  pfn:11355
[   38.149682] page:ffff7e000044d540 count:0 mapcount:0 
mapping:0000000000000000 index:0x0
[   38.165760] flags: 0xfffc00000001000(reserved)
[   38.174676] raw: 0fffc00000001000 ffff7e000044d548 ffff7e000044d548 
0000000000000000
[   38.190230] raw: 0000000000000000 0000000000000000 00000000ffffffff 
0000000000000000
[   38.205783] page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
[   38.218716] bad because of flags: 0x1000(reserved)
[   38.228329] Modules linked in:
[   38.234451] CPU: 5 PID: 2691 Comm: sh Tainted: G    B 
5.0.0 #121
[   38.248604] Hardware name: Huawei Taishan 2280 /D05, BIOS Hisilicon 
D05 IT21 Nemo 2.0 RC0 04/18/2018
[   38.266949] Call trace:
[   38.271844]  dump_backtrace+0x0/0x150
[   38.279185]  show_stack+0x14/0x1c
[   38.285826]  dump_stack+0x8c/0xb0
[   38.292468]  bad_page+0xe4/0x144
[   38.298936]  free_pages_check_bad+0x7c/0x84

...

Thanks,
John

> Thanks,
> Robin.
>
>>> There aren't many drivers using dmam_alloc_*(), let alone which would
>>> also find themselves behind an IOMMU on an Arm system, but it turns out
>>> I actually have another one which can reproduce the BUG() with 5.0-rc.
>>
>> SATA core uses dmam_alloc_*().
>>
>>> I've tried a 4.12 kernel with a bit of instrumentation[1] and sure
>>> enough the devres-managed buffer is freed with the wrong ops[2] even
>>> then. How it manages not to blow up more catastrophically I have no
>>> idea... I guess at best it just leaks the buffers and IOMMU mappings,
>>> and at worst quietly frees random other pages instead.
>>
>> May depend on the actual ops, and whether CMA is used or not.
>>
>> Gr{oetje,eeting}s,
>>
>>                          Geert
>>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
> .
>