[PATCH] common: bootm: only use initrd override if non-empty

[PATCH] common: bootm: only use initrd override if non-empty

[chalianis1]

From: Chali Anis <chalianis1@gmail.com>

OSTree integration in Yocto generates an empty initramfs
file and references it in the boot configuration (under
/boot/loader/ostree-1.conf) to suppress init= kernel arguments.
This caused Barebox to always prefer the override, even when
the initramfs was empty, preventing booting of FIT images
that already contain an embedded initramfs.

Signed-off-by: Chali Anis <chalianis1@gmail.com>
---
 common/bootm.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/common/bootm.c b/common/bootm.c
index 3a2eb262b26a..f31ef546d92c 100644
--- a/common/bootm.c
+++ b/common/bootm.c
@@ -279,14 +279,18 @@ static int bootm_open_initrd_uimage(struct image_data *data)
 const struct resource *
 bootm_load_initrd(struct image_data *data, unsigned long load_address)
 {
+	struct stat st;
 	enum filetype type;
 	int ret;
 
 	if (!IS_ENABLED(CONFIG_BOOTM_INITRD))
 		return NULL;
 
-	if (bootm_get_override(&data->initrd_file, bootm_overrides.initrd_file))
-		goto initrd_file;
+	if (bootm_get_override(&data->initrd_file,
+			       bootm_overrides.initrd_file)) {
+		if (!stat(data->initrd_file, &st) && st.st_size > 0)
+			goto initrd_file;
+	}
 
 	if (data->initrd_res)
 		return data->initrd_res;
-- 
2.34.1

Re: [PATCH] common: bootm: only use initrd override if non-empty

[Sascha Hauer]

Hi,

I have some trouble understanding this patch.

On Tue, Aug 26, 2025 at 02:11:08AM -0400, chalianis1@gmail.com wrote:
> From: Chali Anis <chalianis1@gmail.com>
> 
> OSTree integration in Yocto generates an empty initramfs
> file and references it in the boot configuration (under
> /boot/loader/ostree-1.conf) to suppress init= kernel arguments.
> This caused Barebox to always prefer the override, even when
> the initramfs was empty, preventing booting of FIT images
> that already contain an embedded initramfs.

So you have one initrd specified in /boot/loader/ostree-1.conf and
another one in your FIT image, right?

By default and without this patch I would assume the initrd from the FIT
image takes precedence, right?

> 
> Signed-off-by: Chali Anis <chalianis1@gmail.com>
> ---
>  common/bootm.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/common/bootm.c b/common/bootm.c
> index 3a2eb262b26a..f31ef546d92c 100644
> --- a/common/bootm.c
> +++ b/common/bootm.c
> @@ -279,14 +279,18 @@ static int bootm_open_initrd_uimage(struct image_data *data)
>  const struct resource *
>  bootm_load_initrd(struct image_data *data, unsigned long load_address)
>  {
> +	struct stat st;
>  	enum filetype type;
>  	int ret;
>  
>  	if (!IS_ENABLED(CONFIG_BOOTM_INITRD))
>  		return NULL;
>  
> -	if (bootm_get_override(&data->initrd_file, bootm_overrides.initrd_file))
> -		goto initrd_file;
> +	if (bootm_get_override(&data->initrd_file,
> +			       bootm_overrides.initrd_file)) {

This path is only taken when bootm_overrides.initrd_file is non empty,
so it seems you are booting with boot -o bootm.initrd=/some/initrd

Without this patch you would then end up using /some/initrd as initrd

> +		if (!stat(data->initrd_file, &st) && st.st_size > 0)
> +			goto initrd_file;

Now with this patch you use /some/initrd only when it exists and is non
empty. Otherwise you would end up using the initrd from the FIT image,
the same initrd which would be used if you had not set -o bootm.initrd=/some/initrd.

I think I am misunderstanding something.

Sascha

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