[PATCH V2] arm64: optimized copy_to_user and copy_from_user assembly code

Steve Capper steve.capper at linaro.org
Thu Dec 4 04:27:48 PST 2014

On 3 December 2014 at 20:01, Craig Magina <craig.magina at canonical.com> wrote:
> Could you provide the steps you used to reproduce this issue? I have
> already submitted an SRU to revert this patch, but would like to have
> the method you used to reproduce it for testing. Thanks for reporting
> this.
> --
> Craig Magina

Hi Craig,
It's not easy to reproduce as the problem occurs when the kernel is
copying memory to userspace and experiences a page fault.

I have come across it whilst running "perf record -a" on a system that
is swapping.

Also, building source code under memory pressure (i.e. kernel compile
just after the system has swapped out pages), gave me this problem


More information about the linux-arm-kernel mailing list