On Thu, Jul 30, 2020 at 09:23:44AM +0200, Kurt Kanzenbach wrote: > Hi Vladimir, > > On Wed Jul 29 2020, Vladimir Oltean wrote: > > For more context, here is my original report of the issue: > > https://lkml.org/lkml/2020/6/4/1062 > > > > Just like you, I could not reproduce the RCU stalls and system hang on a > > 5.6-rt kernel, just on mainline and derivatives, using the plain > > defconfig. > > > > The issue is not specific to Layerscape or i.MX8, but rather I was able > > to see the same behavior on Marvell Armada 37xx as well as Qualcomm > > MSM8976. > > > > So, while of course I agree that disabling IRQ time accounting for arm64 > > isn't a real solution, it isn't by far an exaggerated proposal either. > > Nonetheless, the patch is just a RFC and should be treated as such. We > > are at a loss when it comes to debugging this any further and we would > > appreciate some pointers. > > Yeah, sure. I'll try to reproduce this issue first. So it triggers with: > > * arm64 > * mainline, not -rt kernel > * opened serial console > * irq accounting enabled > > Anything else? > > Thanks, > Kurt
Thanks for giving a helping hand, Kurt. The defconfig should be enough. In the interest of full disclosure, the only arm64 device on which we didn't reproduce this was the 16-core LX2160A. But we did reproduce on that with maxcpus=1 though. And also on msm8976 with all 8 cores booted. Just mentioning this in case you're testing on a 16-core system, you might want to reduce the number a bit. Thanks, -Vladimir