Re: v5.4.289 failed to boot with error megasas_build_io_fusion 3219 sge_count (-12) is out of range

["Jürgen Groß" <jgross@suse.com>]

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On 29.01.25 19:35, Harshvardhan Jha wrote:
> 
> On 29/01/25 4:52 PM, Juergen Gross wrote:
>> On 29.01.25 10:15, Harshvardhan Jha wrote:
>>>
>>> On 29/01/25 2:34 PM, Greg KH wrote:
>>>> On Wed, Jan 29, 2025 at 02:29:48PM +0530, Harshvardhan Jha wrote:
>>>>> Hi Greg,
>>>>>
>>>>> On 29/01/25 2:18 PM, Greg KH wrote:
>>>>>> On Wed, Jan 29, 2025 at 02:13:34PM +0530, Harshvardhan Jha wrote:
>>>>>>> Hi there,
>>>>>>>
>>>>>>> On 29/01/25 2:05 PM, Greg KH wrote:
>>>>>>>> On Wed, Jan 29, 2025 at 02:03:51PM +0530, Harshvardhan Jha wrote:
>>>>>>>>> Hi All,
>>>>>>>>>
>>>>>>>>> +stable
>>>>>>>>>
>>>>>>>>> There seems to be some formatting issues in my log output. I have
>>>>>>>>> attached it as a file.
>>>>>>>> Confused, what are you wanting us to do here in the stable tree?
>>>>>>>>
>>>>>>>> thanks,
>>>>>>>>
>>>>>>>> greg k-h
>>>>>>> Since, this is reproducible on 5.4.y I have added stable. The
>>>>>>> culprit
>>>>>>> commit which upon getting reverted fixes this issue is also
>>>>>>> present in
>>>>>>> 5.4.y stable.
>>>>>> What culprit commit?  I see no information here :(
>>>>>>
>>>>>> Remember, top-posting is evil...
>>>>> My apologies,
>>>>>
>>>>> The stable tag v5.4.289 seems to fail to boot with the following
>>>>> prompt in an infinite loop:
>>>>> [   24.427217] megaraid_sas 0000:65:00.0: megasas_build_io_fusion
>>>>> 3273 sge_count (-12) is out of range. Range is:  0-256
>>>>>
>>>>> Reverting the following patch seems to fix the issue:
>>>>>
>>>>> stable-5.4      : v5.4.285             - 5df29a445f3a xen/swiotlb: add
>>>>> alignment check for dma buffers
>>>>>
>>>>> I tried changing swiotlb grub command line arguments but that didn't
>>>>> seem to help much unfortunately and the error was seen again.
>>>>>
>>>> Ok, can you submit this revert with the information about why it should
>>>> not be included in the 5.4.y tree and cc: everyone involved and then we
>>>> will be glad to queue it up.
>>>>
>>>> thanks,
>>>>
>>>> greg k-h
>>>
>>> This might be reproducible on other stable trees and mainline as well so
>>> we will get it fixed there and I will submit the necessary fix to stable
>>> when everything is sorted out on mainline.
>>
>> Right. Just reverting my patch will trade one error with another one (the
>> one which triggered me to write the patch).
>>
>> There are two possible ways to fix the issue:
>>
>> - allow larger DMA buffers in xen/swiotlb (today 2MB are the max.
>> supported
>>    size, the megaraid_sas driver seems to effectively request 4MB)
> 
> This seems relatively simpler to implement but I'm not sure whether it's
> the most optimal approach

Just making the static array larger used to hold the frame numbers for the
buffer seems to be a waste of memory for most configurations.

I'm thinking of an allocated array using the max needed size (replace a
former buffer with a larger one if needed).


Juergen

Juergen

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