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Sender: Guenter Roeck <groeck7@gmail.com>
Date: Mon, 18 Mar 2024 10:09:17 -0700
From: Guenter Roeck <linux@roeck-us.net>
To: Frank Rowand <frowand.list@gmail.com>
Cc: Rob Herring <robh+dt@kernel.org>,
	=?iso-8859-1?Q?Cl=E9ment_L=E9ger?= <clement.leger@bootlin.com>,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	Lizhi Hou <lizhi.hou@xilinx.com>,
	Allan Nielsen <allan.nielsen@microchip.com>,
	Horatiu Vultur <horatiu.vultur@microchip.com>,
	Steen Hegelund <steen.hegelund@microchip.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: Re: [PATCH v4 1/2] of: create of_root if no dtb provided
Message-ID: <886049ed-4f5f-4e17-86f4-1245024ade3a@roeck-us.net>
References: <20230317053415.2254616-1-frowand.list@gmail.com>
 <20230317053415.2254616-2-frowand.list@gmail.com>
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In-Reply-To: <20230317053415.2254616-2-frowand.list@gmail.com>

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@gmail.com>

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