Re: [PATCH v4 1/2] of: create of_root if no dtb provided

[Guenter Roeck]

Hi,

On Fri, Mar 17, 2023 at 12:34:14AM -0500, Frank Rowand wrote:
> When enabling CONFIG_OF on a platform where of_root is not populated by
> firmware, we end up without a root node. In order to apply overlays and
> create subnodes of the root node, we need one. Create this root node
> by unflattening an empty builtin dtb.
> 
> If firmware provides a flattened device tree (FDT) then the FDT is
> unflattened via setup_arch().  Otherwise setup_of(), which is called
> immediately after setup_arch(), will create the default root node
> if it does not exist.
> 
> Signed-off-by: Frank Rowand <frowand.list@xxxxxxxxx>

This patch results in a crash on nios2.

Building nios2:10m50-ghrd:10m50_defconfig:10m50_devboard.dts ... running ...R failed (crashed)
------------
qemu log:
earlycon: uart8250 at MMIO32 0x18001600 (options '')
printk: legacy bootconsole [uart8250] enabled
Linux version 6.8.0-11409-gf6cef5f8c37f (groeck@desktop) (nios2-linux-gcc (GCC) 11.4.0, GNU ld (GNU Binutils) 2.40) #1 Sun Mar 17 23:38:59 PDT 2024
Kernel panic - not syncing: early_init_dt_alloc_memory_arch: Failed to allocate 72 bytes align=0x40
---[ end Kernel panic - not syncing: early_init_dt_alloc_memory_arch: Failed to allocate 72 bytes align=0x40 ]---

Reverting this patch fixes the problem.

Guenter