On 4.02.2022 18:17, Sricharan Ramabadhran wrote: > > On 2/2/2022 12:54 PM, Sricharan Ramabadhran wrote: >> Hi Konrad/Miquel, >> >> On 2/1/2022 9:21 PM, Konrad Dybcio wrote: >>> >>> On 01/02/2022 14:52, Miquel Raynal wrote: >>>> Hi Konrad, >>>> >>>> konrad.dybcio@xxxxxxxxxxxxxx wrote on Mon, 31 Jan 2022 20:54:12 +0100: >>>> >>>>> On 31/01/2022 15:13, Sricharan Ramabadhran wrote: >>>>>> Hi Konrad, >>>>>> >>>>>> On 1/31/2022 3:39 PM, Konrad Dybcio wrote: >>>>>>> On 28/01/2022 18:50, Sricharan Ramabadhran wrote: >>>>>>>> Hi Konrad, >>>>>>>> >>>>>>>> On 1/28/2022 9:55 AM, Sricharan Ramabadhran wrote: >>>>>>>>> Hi Miquel, >>>>>>>>> >>>>>>>>> On 1/26/2022 4:12 PM, Miquel Raynal wrote: >>>>>>>>>> Hi Mani, >>>>>>>>>> >>>>>>>>>> mani@xxxxxxxxxx wrote on Wed, 26 Jan 2022 16:03:16 +0530: >>>>>>>>>>> On Wed, Jan 26, 2022 at 11:16:13AM +0100, Miquel Raynal wrote: >>>>>>>>>>>> Hello, >>>>>>>>>>>> >>>>>>>>>>>> miquel.raynal@xxxxxxxxxxx wrote on Fri, 14 Jan 2022 08:27:18 +0100: >>>>>>>>>>>>> Hi Konrad, >>>>>>>>>>>>> >>>>>>>>>>>>> konrad.dybcio@xxxxxxxxxxxxxx wrote on Thu, 13 Jan 2022 19:44:26 >>>>>>>> +0100: >>>>>>>>>>>>>> While I have absolutely 0 idea why and how, running >>>>>>>>> clear_bam_transaction >>>>>>>>>>>>>> when READID is issued makes the DMA totally clog up and refuse >>>>>>>>> to function >>>>>>>>>>>>>> at all on mdm9607. In fact, it is so bad that all the data >>>>>>>>> gets garbled >>>>>>>>>>>>>> and after a short while in the nand probe flow, the CPU >>>>>>>>> decides that >>>>>>>>>>>>>> sepuku is the only option. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Removing _READID from the if condition makes it work like a >>>>>>>>> charm, I can >>>>>>>>>>>>>> read data and mount partitions without a problem. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxx> >>>>>>>>>>>>>> --- >>>>>>>>>>>>>> This is totally just an observation which took me an inhumane >>>>>>>>> amount of >>>>>>>>>>>>>> debug prints to find.. perhaps there's a better reason behind >>>>>>>>> this, but >>>>>>>>>>>>>> I can't seem to find any answers.. Therefore, this is a BIG RFC! >>>>>>>>>>>>> I'm adding two people from codeaurora who worked a lot on this >>>>>>>> driver. >>>>>>>>>>>>> Hopefully they will have an idea :) >>>>>>>>>>>> Sadre, I've spent a significant amount of time reviewing your >>>>>>> patches, >>>>>>>>>>>> now it's your turn to not take a month to answer to your peers >>>>>>>>>>>> proposals. >>>>>>>>>>>> >>>>>>>>>>>> Please help reviewing this patch. >>>>>>>>>>> Sorry. I was hoping that Qcom folks would chime in as I don't >>>>>> have any idea >>>>>>>>>>> about the mdm9607 platform. It could be that the mail server >>>>>> migration from >>>>>>>>>>> codeaurora to quicinc put a barrier here. >>>>>>>>>>> >>>>>>>>>>> Let me ping them internally. >>>>>>>>>> Oh, ok, I didn't know. Thanks! >>>>>>>>> Sorry Miquel, somehow we did not get this email in our inbox. >>>>>>>>> Thanks to Mani for pinging us, we will test this up today and >>>> get back. >>>>>>>> While we could not reproduce this issue on our ipq boards (do >>> not have a mdm9607 right now) and >>>>>>>> issue does not look any obvious. >>>>>>>> can you please give the debug logs that you did for the above >>> stage by stage ? >>>>>>> I won't have access to the board for about two weeks, sorry. >>>>>>> >>>>>>> When I get to it, I'll surely try to send you the logs, though there >>>>>>> >>>>>>> wasn't much more than just something jumping to who-knows-where >>>>>>> >>>>>>> after clear_bam_transaction was called, resulting in values >> associated with >>>>>>> >>>>>>> the NAND being all zeroed out in pr_err/_debug/etc. >>>>>>> >>>>>> Ok sure. So was the READID command itself failing (or) the > subsequent one ? >>>>>> We can check which parameter reset by the clear_bam_transaction is > causing the >>>>>> failure. Meanwhile, looping in Pradeep who has access to the > board, so in a better >>>>>> position to debug. >>>>> I'm sorry I have so few details on hand, and no kernel tree (no access to that machine either, for now). >>>>> >>>>> >>>>> I will try to describe to the best of my abilities what I recall. >>>>> >>>>> >>>>> My methodology of making sure things don't go haywire was to print the oob size >>>>> >>>>> of our NAND basically every two lines of code (yes, i was very desperate at one point), >>>>> >>>>> as that was zeroed out when *the bug* happened, >>>> This does look like a pointer error at some point and some kernel data >>>> has been corrupted very badly by the driver. >>>> >>>>> leading to a kernel bug/panic/stall >>>>> >>>>> (can't recall what exactly it was, but it said something along the lines of "no support for >>>>> >>>>> oob size 0" and then it didn't fail graceully, leading to some bad jumps and ultimately >>>>> >>>>> a dead platform..) >>>>> >>>>> >>>>> after hours of digging, I found out that everything goes fine until clear_bam_transaction is called, >>>> Do you remember if this function was called for the first time when >>>> this happened? >>> >>> I think so, if I recall correctly there are no more callers in this path, as readid is the first nand command executed in flash probe flow. >>> >>> >>> >>>> >>>>> after that gets executed every nand op starts reading all zeroes (for example in JEDEC ID check) >>>>> >>>>> so I added the changes from this patch, and things magically started working... My suspicion is >>>>> >>>>> that the underlying FIFO isn't fully drained (is it a FIFO on 9607? bah, i work on too many socs at once) >>>> I don't see it in the list of supported devices, what's the exact >>>> compatible used? >>> >>> qcom,ipq4019-nand >>> >>> >>> >>>> >>>>> and this function only makes Linux think it is, without actually draining it, and the leftover >>>>> >>>>> commands get executed with some parts of them getting overwritten, resulting in the >>>>> >>>>> famous garbage in - garbage out situation, but that's only a guesstimate.. >>>> I would bet for a non allocated bam-ish pointer that is reset to zero >>>> in the clear_bam_transaction() helper. >>>> >>>> Can you get your hands on the board again? >>> >>> Sure, but as I mentioned previously, only in about 2 weeks, I can't really do any dev before then.. :( >>> >>> >>> >>>> It would be nice to check if the allocation always occurs before use, >>>> and if yes on how much bytes. >>>> >>>> If the pointer is not dangling, then perhaps something else smashes >>>> that pointer. >>> >>> >>> Konrad >>> >>>> >>>>> Do note this somehow worked fine on 5.11 and then broke on 5.12/13. I went as far as replacing most >>>>> >>>>> of the kernel with the updated/downgraded parts via git checkout (i tried many combinations), >>>>> >>>>> to no avail.. I even tried different compilers and optimization levels, thinking it could have been >>>>> >>>>> a codegen issue, but no luck either. >>>>> >>>>> >>>>> I.. do understand this email is a total mess to read, as much as it was to write, but >>>>> >>>>> without access to my code and the machine itself I can't give you solid details, and >>>>> >>>>> the fact this situation is far from ordinary doesn't help either.. >>>>> >>>>> >>>>> The latest (ancient, not quite pretty, but probably working if my memory is correct) version of my patches >>>>> >>>>> for the mdm9607 is available at [1], I will push the new revision after I get access to the workstation. >>>>> >> + few more who have access to the board. >> >> Going by the description, for kernel corruption, we can try out a KASAN build. >> Since you have mentioned it worked till 5.11, you bisected the driver till 5.11 head and it worked ? >> > Tried running a KASAN enabled image on IPQ board, but no luck. Nothing came out. > Only if someone with the board can help here, we can proceed > > > Regards, > Sricharan > I have the board with me again. Please tell me where do we start :) Konrad
