arm kernel oops in highmem.c with 4.2

[linux@arm.linux.org.uk (Russell King - ARM Linux)]

On Wed, Aug 05, 2015 at 11:01:01AM +0100, Peter Robinson wrote:
> Hi All,
> 
> On Fedora 23 with recent 4.2 kernels we're seeing a crash (below) in
> highmem.c on a fairly regular occurrence across a number of different
> SoCs, I've seen it with at least AllWinner A20, i.MX6Q, Tegra2 and 124
> with both a LPAE and non LPAE kernel, seen it happen when doing a
> number of different things but regenerating a initrd, applying updates
> (dnf/yum) and starting X are all pretty good triggers.

I've yet to see any problems with mainline 4.2-rc5 kernels on any of my
iMX6 platforms, which includes initramfs regeneration, apt-get updates
and X.

> [71751.658105] ------------[ cut here ]------------
> [71751.658153] kernel BUG at arch/arm/mm/highmem.c:114!

Well, in mainline kernels, the BUG is on line 113, not line 114.  So at
least this file is modified from mainline kernels.  Maybe the problem is
caused by patches applied to Fedora kernels?

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