NFS rootfs fails on 3.16 about ci20_linux

[ZubairLK]

Disabling CONFIG_HIGHMEM in kernel options results in a working nfs mount and it works.

bootargs.

console=ttyS4,115200 console=ttyS0 mem=256M@0x0 root=/dev/nfs nfsroot=192.168.154.89:/export,nolock nfsrootdebug ip=dhcp devtmpfs.mount=1 rw rootwait clk_ignore_unused

Disabling HIGHMEM is not a fix. But a workaround. The actual bug is somewhere in highmem/cache.

Found similar bug when trying to boot NAND rootfs using 3.16.
Init would fail.

Booting 3.16 via a rootfs using mmc would work. Then ubiattach /dev/mtd3 would work too.
Mounting partition would work too. But trying to execute any binary in the partition would give random errors.
i.e.

ubiattach /dev/ubi_ctrl -m 3
mount -t ubifs ubi0:root /media/
cd /media/bin
./ls
illegal instruction
./ls
seg fault

errors like this

Trying again and again would result in it working after a while.

This is what happens during init. It is not an init bug. The binary doesn't execute when the NAND block device is mounted.

[ZubairLK]

#18