Re: nios2 crash/hang in mainline due to 'lib: update LZ4 compressor module'

[Guenter Roeck]

On 03/07/2017 04:46 AM, Tobias Klauser wrote:
[ ... ]

> Linux version 4.11.0-rc1-dirty (tobiask@ziws08) (gcc version 7.0.1 20170226 (experimental) (GCC) ) #46 Tue Mar 7 13:40:53 CET 2017
> bootconsole [early0] enabled
> Early console on uart16650 initialized at 0xf8001600
> OF: fdt: Error -11 processing FDT
> Kernel panic - not syncing: setup_cpuinfo: No CPU found in devicetree!
>
> ---[ end Kernel panic - not syncing: setup_cpuinfo: No CPU found in devicetree!
>
> Looks like the in-memory device tree somehow gets corrupted. Not sure
> yet why and how this is linked to the Kconfig options selected but at
> least we now have a possibility to use debug messages earlier on.

I think I found the problem. In unflatten_and_copy_device_tree(), with added
debug information:

OF: fdt: initial_boot_params=c861e400, dt=c861f000 size=28874 (0x70ca)

... and then initial_boot_params is copied to dt, which results in corrupted
fdt since the memory overlaps. Looks like the initial_boot_params memory
is not reserved and (re-)allocated by early_init_dt_alloc_memory_arch().

Guenter