Messages in this thread | | | Date | Thu, 30 Jun 2022 07:20:58 +0200 | Subject | Re: Regression: memory corruption on Atmel SAMA5D31 | From | Peter Rosin <> |
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Hi!
2022-06-27 at 18:53, Tudor.Ambarus@microchip.com wrote: > On 6/27/22 15:26, Tudor.Ambarus@microchip.com wrote: >> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe >> >> On 6/21/22 13:46, Peter Rosin wrote: >>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe >>> >>> 2022-06-20 at 16:22, Tudor.Ambarus@microchip.com wrote: >>>> >>>>> >>>>> git@github.com:ambarus/linux-0day.git, branch dma-regression-hdmac-v5.18-rc7-4th-attempt >>>>> >>>> >>>> Hi, Peter, >>>> >>>> I've just forced pushed on this branch, I had a typo somewhere and with that fixed I could >>>> no longer reproduce the bug. Tested for ~20 minutes. Would you please test last 3 patches >>>> and tell me if you can still reproduce the bug? >>> >>> Hi! >>> >>> I rebased your patches onto my current branch which is v5.18.2 plus a few unrelated >>> changes (at least they are unrelated after removing the previous workaround to disable >>> nand-dma entirely). >>> >>> The unrelated patches are two backports so that drivers recognize new compatibles [1][2], >>> which should be completely harmless, plus a couple of proposed fixes that happens to fix >>> eeprom issues with the at91 I2C driver from Codrin Ciubotariu [3]. >>> >>> On that kernel, I can still reproduce. It seems a bit harder to reproduce the problem now >>> though. If the system is otherwise idle, the sha256sum test did not reproduce in a run of >>> 150+ attempts, but if I let the "real" application run while I do the test, I get a failure rate >>> of about 10%, see below. The real application burns some CPU (but not all of it) and >>> communicates with HW using I2C, native UARTs and two of the four USB-serial ports >>> (FTDI, with the latency set to 1ms as mentioned earlier), so I guess there is more DMA >>> pressure or something? There is a 100mbps network connection, but it was left "idle" >>> during this test. >>> >> >> Thanks, Peter. >> I got back to the office, I'm rechecking what could go wrong. >> > > Hi, Peter, > > Would you please help me with another round of testing? I have difficulties > in reproducing the bug and maybe you can speed up the process while I copy > your testing setup. I made two more patches on top of the same branch [1]. > My assumption is that the last problem that you saw is that a transfer > could be started multiple times. I think these are the last less invasive > changes that I try, I'll have to rewrite the logic anyway. > > Thanks! > > [1] To github.com:ambarus/linux-0day.git > cbb2ddca4618..79c7784dbcf2 dma-regression-hdmac-v5.18-rc7-4th-attempt -> dma-regression-hdmac-v5.18-rc7-4th-attempt
I was out of office, but I managed to get a test running over night and can report that It still fails. This is a longer run of about 500 with a failure rate of 5% compared to the last time when the failure rate was 10%. I tend to think that the observed difference in failure rate may well be statistical noise, but who knows? Would it be useful with a longer run without the last two patches to see if they make a difference?
Cheers, Peter
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