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

[Harshvardhan Jha <harshvardhan.j.jha@xxxxxxxxxx>]

Hi there,

On 31/01/25 5:35 PM, Harshvardhan Jha wrote:
> On 30/01/25 6:05 PM, Jürgen Groß wrote:
>> On 29.01.25 19:46, Harshvardhan Jha wrote:
>>> On 30/01/25 12:13 AM, Jürgen Groß wrote:
>>>> 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.
>>> Yep definitely not required in most cases.
>>>> I'm thinking of an allocated array using the max needed size (replace a
>>>> former buffer with a larger one if needed).
>>> This seems like the right way to go.
>> Can you try the attached patch, please? I don't have a system at hand
>> showing the problem.
> I tried this and got this error in an infinite loop again:
> [   25.827922] megaraid_sas 0000:65:00.0: megasas_build_io_fusion 3273
> sge_count (-12) is out of range. Range is:  0-256
> [   25.828447] megaraid_sas 0000:65:00.0: Error building command


Would this require a change in the megasas driver also as simply
changing xen code isn't fixing the issue?

Harshvardhan


>>
>> Juergen