[ipxe-devel] initrd corruption since commit ef038491858cb51f8aa17b1f6e50444d2e627413

[Sven Dreyer]

Am 26.04.25 um 02:07 schrieb Michael Brown:
> I'm unable to reproduce your problem, sorry.  But since you have a 
> bisection result: try starting from commit b65f67d44 (i.e. the previous 
> commit, which you say works for you), and add in one change at a time 
> from commit ef0384918.  For example, start by adding the first changed 
> line in bzimage.c:
> 
>          /* Calculate lowest usable address */
> -       bottom = userptr_add ( bzimg->pm_kernel, bzimg->pm_sz );
> +       bottom = ( bzimg->pm_kernel + bzimg->pm_sz );
> 
> Test after each changed line, and see which changed line introduces your 
> issue.
> 
> Thanks,
> 
> Michael


Thanks for your investigation and support, Michael!

This is the change that causes the boot problem on my Debian nfsroot system:

src/arch/x86/image/initrd.c
	/* Copy any remaining initrds (e.g. embedded images) to the region */
	for_each_image ( initrd ) {
-		if ( userptr_diff ( initrd->data, top ) >= 0 ) {
+		if ( initrd->data >= top ) {
			len = ( ( initrd->len + INITRD_ALIGN - 1 ) &
				~( INITRD_ALIGN - 1 ) );


And this is the change that makes wimboot 2.8.0 fail to boot my Windows 
PE 10 x86_64:

src/arch/x86/image/initrd.c
		/* Find the highest image not yet in its final position */
  		highest = NULL;
  		for_each_image ( initrd ) {
- 			if ( ( userptr_diff ( initrd->data, current ) < 0 ) &&
+ 			if ( ( initrd->data < current ) &&
  			     ( ( highest == NULL ) ||

I have attached a few screenshots from qemu. The output of imgstat seems 
to be the same with and without the changes to initrd.c.

Thanks and best regards,
Sven
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