Messages in this thread | | | Date | Wed, 2 Jun 2021 15:28:22 +0200 | From | Maxime Ripard <> | Subject | Re: Kernel Panic in skb_release_data using genet |
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On Tue, Jun 01, 2021 at 11:33:18AM +0200, nicolas saenz julienne wrote: > On Mon, 2021-05-31 at 19:36 -0700, Florian Fainelli wrote: > > > That is also how I boot my Pi4 at home, and I suspect you are right, if > > > the VPU does not shut down GENET's DMA, and leaves buffer addresses in > > > the on-chip descriptors that point to an address space that is managed > > > totally differently by Linux, then we can have a serious problem and > > > create some memory corruption when the ring is being reclaimed. I will > > > run a few experiments to test that theory and there may be a solution > > > using the SW_INIT reset controller to have a big reset of the controller > > > before handing it over to the Linux driver. > > > > Adding a WARN_ON(reg & DMA_EN) in bcmgenet_dma_disable() has not shown > > that the TX or RX DMA have been left running during the hand over from > > the VPU to the kernel. I checked out drm-misc-next-2021-05-17 to reduce > > as much as possible the differences between your set-up and my set-up > > but so far have not been able to reproduce the crash in booting from NFS > > repeatedly, I will try again. > > FWIW I can reproduce the error too. That said it's rather hard to reproduce, > something in the order of 1 failure every 20 tries.
Yeah, it looks like it's only from a cold boot and comes in "bursts", where you would get like 5 in a row and be done with it for a while.
Maxime
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