Bug 205201 - overflow of DMA mask and bus mask

Christian Zigotzky chzigotzky at xenosoft.de
Mon Nov 11 23:22:55 AEDT 2019


On 11 November 2019 at 09:16 am, Christian Zigotzky wrote:
> On 11 November 2019 at 09:12 am, Christian Zigotzky wrote:
>> On 10 November 2019 at 08:27 am, Christian Zigotzky wrote:
>>> On 07 November 2019 at 10:53 am, Christian Zigotzky wrote:
>>>> On 05 November 2019 at 05:28 pm, Christoph Hellwig wrote:
>>>>> On Tue, Nov 05, 2019 at 08:56:27AM +0100, Christian Zigotzky wrote:
>>>>>> Hi All,
>>>>>>
>>>>>> We still have DMA problems with some PCI devices. Since the 
>>>>>> PowerPC updates
>>>>>> 4.21-1 [1] we need to decrease the RAM to 3500MB (mem=3500M) if 
>>>>>> we want to
>>>>>> work with our PCI devices. The FSL P5020 and P5040 have these 
>>>>>> problems
>>>>>> currently.
>>>>>>
>>>>>> Error message:
>>>>>>
>>>>>> [   25.654852] bttv 1000:04:05.0: overflow 
>>>>>> 0x00000000fe077000+4096 of DMA
>>>>>> mask ffffffff bus mask df000000
>>>>>>
>>>>>> All 5.x Linux kernels can't initialize a SCSI PCI card anymore so 
>>>>>> booting
>>>>>> of a Linux userland isn't possible.
>>>>>>
>>>>>> PLEASE check the DMA changes in the PowerPC updates 4.21-1 [1]. 
>>>>>> The kernel
>>>>>> 4.20 works with all PCI devices without limitation of RAM.
>>>>> Can you send me the .config and a dmesg?  And in the meantime try the
>>>>> patch below?
>>>>>
>>>>> ---
>>>>> >From 4d659b7311bd4141fdd3eeeb80fa2d7602ea01d4 Mon Sep 17 00:00:00 
>>>>> 2001
>>>>> From: Nicolas Saenz Julienne <nsaenzjulienne at suse.de>
>>>>> Date: Fri, 18 Oct 2019 13:00:43 +0200
>>>>> Subject: dma-direct: check for overflows on 32 bit DMA addresses
>>>>>
>>>>> As seen on the new Raspberry Pi 4 and sta2x11's DMA implementation 
>>>>> it is
>>>>> possible for a device configured with 32 bit DMA addresses and a 
>>>>> partial
>>>>> DMA mapping located at the end of the address space to overflow. It
>>>>> happens when a higher physical address, not DMAable, is translated to
>>>>> it's DMA counterpart.
>>>>>
>>>>> For example the Raspberry Pi 4, configurable up to 4 GB of memory, 
>>>>> has
>>>>> an interconnect capable of addressing the lower 1 GB of physical 
>>>>> memory
>>>>> with a DMA offset of 0xc0000000. It transpires that, any attempt to
>>>>> translate physical addresses higher than the first GB will result 
>>>>> in an
>>>>> overflow which dma_capable() can't detect as it only checks for
>>>>> addresses bigger then the maximum allowed DMA address.
>>>>>
>>>>> Fix this by verifying in dma_capable() if the DMA address range 
>>>>> provided
>>>>> is at any point lower than the minimum possible DMA address on the 
>>>>> bus.
>>>>>
>>>>> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne at suse.de>
>>>>> ---
>>>>>   include/linux/dma-direct.h | 8 ++++++++
>>>>>   1 file changed, 8 insertions(+)
>>>>>
>>>>> diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
>>>>> index adf993a3bd58..6ad9e9ea7564 100644
>>>>> --- a/include/linux/dma-direct.h
>>>>> +++ b/include/linux/dma-direct.h
>>>>> @@ -3,6 +3,7 @@
>>>>>   #define _LINUX_DMA_DIRECT_H 1
>>>>>     #include <linux/dma-mapping.h>
>>>>> +#include <linux/memblock.h> /* for min_low_pfn */
>>>>>   #include <linux/mem_encrypt.h>
>>>>>     #ifdef CONFIG_ARCH_HAS_PHYS_TO_DMA
>>>>> @@ -27,6 +28,13 @@ static inline bool dma_capable(struct device 
>>>>> *dev, dma_addr_t addr, size_t size)
>>>>>       if (!dev->dma_mask)
>>>>>           return false;
>>>>>   +#ifndef CONFIG_ARCH_DMA_ADDR_T_64BIT
>>>>> +    /* Check if DMA address overflowed */
>>>>> +    if (min(addr, addr + size - 1) <
>>>>> +        __phys_to_dma(dev, (phys_addr_t)(min_low_pfn << 
>>>>> PAGE_SHIFT)))
>>>>> +        return false;
>>>>> +#endif
>>>>> +
>>>>>       return addr + size - 1 <=
>>>>>           min_not_zero(*dev->dma_mask, dev->bus_dma_mask);
>>>>>   }
>>>> Hello Christoph,
>>>>
>>>> Thanks a lot for your patch! Unfortunately this patch doesn't solve 
>>>> the issue.
>>>>
>>>> Error messages:
>>>>
>>>> [    6.041163] bttv: driver version 0.9.19 loaded
>>>> [    6.041167] bttv: using 8 buffers with 2080k (520 pages) each 
>>>> for capture
>>>> [    6.041559] bttv: Bt8xx card found (0)
>>>> [    6.041609] bttv: 0: Bt878 (rev 17) at 1000:04:05.0, irq: 19, 
>>>> latency: 128, mmio: 0xc20001000
>>>> [    6.041622] bttv: 0: using: Typhoon TView RDS + FM Stereo / KNC1 
>>>> TV Station RDS [card=53,insmod option]
>>>> [    6.042216] bttv: 0: tuner type=5
>>>> [    6.111994] bttv: 0: audio absent, no audio device found!
>>>> [    6.176425] bttv: 0: Setting PLL: 28636363 => 35468950 (needs up 
>>>> to 100ms)
>>>> [    6.200005] bttv: PLL set ok
>>>> [    6.209351] bttv: 0: registered device video0
>>>> [    6.211576] bttv: 0: registered device vbi0
>>>> [    6.214897] bttv: 0: registered device radio0
>>>> [  114.218806] bttv 1000:04:05.0: overflow 0x00000000ff507000+4096 
>>>> of DMA mask ffffffff bus mask df000000
>>>> [  114.218848] Modules linked in: rfcomm bnep tuner_simple 
>>>> tuner_types tea5767 tuner tda7432 tvaudio msp3400 bttv tea575x 
>>>> tveeprom videobuf_dma_sg videobuf_core rc_core videodev mc btusb 
>>>> btrtl btbcm btintel bluetooth uio_pdrv_genirq uio ecdh_generic ecc
>>>> [  114.219012] [c0000001ecddf720] [80000000008ff6e8] 
>>>> .buffer_prepare+0x150/0x268 [bttv]
>>>> [  114.219029] [c0000001ecddf860] [80000000008fff6c] 
>>>> .bttv_qbuf+0x50/0x64 [bttv]
>>>>
>>>> -----
>>>>
>>>> Trace:
>>>>
>>>> [  462.783184] Call Trace:
>>>> [  462.783187] [c0000001c6c67420] [c0000000000b3358] 
>>>> .report_addr+0xb8/0xc0 (unreliable)
>>>> [  462.783192] [c0000001c6c67490] [c0000000000b351c] 
>>>> .dma_direct_map_page+0xf0/0x128
>>>> [  462.783195] [c0000001c6c67530] [c0000000000b35b0] 
>>>> .dma_direct_map_sg+0x5c/0xac
>>>> [  462.783205] [c0000001c6c675e0] [8000000000862e88] 
>>>> .__videobuf_iolock+0x660/0x6d8 [videobuf_dma_sg]
>>>> [  462.783220] [c0000001c6c676b0] [8000000000854274] 
>>>> .videobuf_iolock+0x98/0xb4 [videobuf_core]
>>>> [  462.783271] [c0000001c6c67720] [80000000008686e8] 
>>>> .buffer_prepare+0x150/0x268 [bttv]
>>>> [  462.783276] [c0000001c6c677c0] [8000000000854afc] 
>>>> .videobuf_qbuf+0x2b8/0x428 [videobuf_core]
>>>> [  462.783288] [c0000001c6c67860] [8000000000868f6c] 
>>>> .bttv_qbuf+0x50/0x64 [bttv]
>>>> [  462.783383] [c0000001c6c678e0] [80000000007bf208] 
>>>> .v4l_qbuf+0x54/0x60 [videodev]
>>>> [  462.783402] [c0000001c6c67970] [80000000007c1eac] 
>>>> .__video_do_ioctl+0x30c/0x3f8 [videodev]
>>>> [  462.783421] [c0000001c6c67a80] [80000000007c3c08] 
>>>> .video_usercopy+0x18c/0x3dc [videodev]
>>>> [  462.783440] [c0000001c6c67c00] [80000000007bb14c] 
>>>> .v4l2_ioctl+0x60/0x78 [videodev]
>>>> [  462.783460] [c0000001c6c67c90] [80000000007d3c48] 
>>>> .v4l2_compat_ioctl32+0x9b4/0x1850 [videodev]
>>>> [  462.783468] [c0000001c6c67d70] [c0000000001ad9cc] 
>>>> .__se_compat_sys_ioctl+0x284/0x127c
>>>> [  462.783473] [c0000001c6c67e20] [c00000000000067c] 
>>>> system_call+0x60/0x6c
>>>> [  462.783475] Instruction dump:
>>>> [  462.783477] 40fe0044 60000000 892255d0 2f890000 40fe0020 
>>>> 3c82ffc5 39200001 60000000
>>>> [  462.783483] 38842029 992255d0 485ad0d9 60000000 <0fe00000> 
>>>> 38210070 e8010010 7c0803a6
>>>> [  462.783490] ---[ end trace b677d4a00458e277 ]---
>>>>
>>>> -----
>>>>
>>>> dmesg fsl p5040: https://bugzilla.kernel.org/attachment.cgi?id=285813
>>>>
>>>> Kernel 5.4-rc6 config for the Cyrus+ board and for the QEMU ppce500 
>>>> board (CPU: P5040 and P5020): 
>>>> https://bugzilla.kernel.org/attachment.cgi?id=285815
>>>>
>>>> Bug report: https://bugzilla.kernel.org/show_bug.cgi?id=205201
>>>>
>>>> Thanks for your help,
>>>>
>>>> Christian
>>>
>>> Christoph,
>>>
>>> Do you have another patch for testing or shall I bisect?
>>>
>>> Thanks,
>>> Christian
>>
>> Hi Christoph,
>>
>> I have seen that I have activated the kernel config option 
>> CONFIG_ARCH_DMA_ADDR_T_64BIT. That means your code in your patch 
>> won't work if this kernel option is enabled.
>>
>> +#ifndef CONFIG_ARCH_DMA_ADDR_T_64BIT
>> +    /* Check if DMA address overflowed */
>> +    if (min(addr, addr + size - 1) <
>> +        __phys_to_dma(dev, (phys_addr_t)(min_low_pfn << PAGE_SHIFT)))
>> +        return false;
>> +#endif
>>
>> I will delete the lines with ifndef and endif and will try it again.
>>
>> Cheers,
>> Christian
>
> Christoph,
>
> I have seen that the patch above isn't from you. It's from Nicolas 
> Saenz Julienne.
>
> Cheers,
> Christian

Christoph,

Now, I can definitely say that this patch does not solve the issue.

Do you have another patch for testing or shall I bisect?

Thanks,
Christian


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