On Sun, 26 May 2019 at 13:11, Stefan Wahren <wahrenst@xxxxxxx> wrote:
>
> Hi,
>
> i want to remind about an issue which was originally reported by Wayne
> Piekarski [1]. I'm able to reproduce this oops with Mainline Linux 5.0.2
> on a Raspberry Pi 3B+ (arm64/defconfig) and according to Jan Kratochvil
> [2] this applies to 5.1.0 and 5.2.0.
>
> The crash is reproducible since commit c55191e96ca ("arm64: mm: apply
> r/o permissions of VM areas to its linear alias as well"), but the root
> cause of the crash was introduced much earlier with commit 56406e017a88
> ("usb: dwc2: Fix DMA alignment to start at allocated boundary").
>
> I tested successfully the following workarounds with the RPi 3B+:
>
> 1) Disable RODATA_FULL_DEFAULT_ENABLED
>
> 2) revert commit 56406e017a88 ("usb: dwc2: Fix DMA alignment to start at
> allocated boundary")
>
> It would be nice if someone can come up with a proper solution.
>
> Regards
> Stefan
>
> [1] - https://marc.info/?l=linux-usb&m=155440243702650&w=2
> [2] - https://bugzilla.kernel.org/show_bug.cgi?id=203149
>
Hello.
This is just a shot in the dark but have you tried to apply DMA cache
alignment issue fix [1] as a third workaround alternative?
If it helps the fix should be merged upstream.
[1] - https://patchwork.kernel.org/patch/10817377/
Br,
--
Antti
