bug - bootflow: grub efi crashes when bootflow selected explicitly

[Shantur Rathore]

Hi Simon,

I have figured out the cause of the crash.
It happens here -
https://github.com/u-boot/u-boot/blob/master/boot/bootflow.c#L470
while doing - free(bflow->buf)

As I understand it,
- Just before starting kernel EFI binary calls usb-uclass->usb_stop()
- This starts removing all devices in my case ( 6x usb_hub, 2x
partition, 1x blk, 2x bootdev, 1x usb_maas_storage)
- While removing bootdev, it ends up calling bootdev-uclass ->
bootdev_pre_unbind -> bootdev_clear_bootflows which calls
bootflow->bootflow_remove and bootflow_free

I don't know why this buf cannot be freed, is it because the EFI
binary in the buffer is still being used ( efi/boot/bootaa64.efi ) ?
But commenting this line out fixes the crash and linux boots happily.

Fixing this properly is above my pay grade as of now.

Kind regards,
Shantur

On Wed, Nov 15, 2023 at 3:58 PM Simon Glass <sjg at chromium.org> wrote:
>
> Hi Shantur,
>
> On Wed, 15 Nov 2023 at 08:23, Shantur Rathore <i at shantur.com> wrote:
> >
> > Hi Simon,
> >
> > >
> > > Is this the blue port on top of the USB-C connector?
> > >
> > Yes, that's correct.
> > For my drive I needed -
> > https://patchwork.ozlabs.org/project/uboot/patch/20231110141311.512334-1-i@shantur.com/
> >
> > >
> > > Which version of Armbian / download link?
> > >
> > https://redirect.armbian.com/rockpro64/Bookworm_current
> >
> > > Yes it is scanning first, before reading the efi app, etc.
> > >
> > > I have the same hardware so may be able to dig into this.
> >
> > Sorry, I meant to ask if anything specific to USB.
> > I see it loads efi from the network or disk and calls bootefi with the
> > loaded address.
> > I don't know deep boot / efi stuff, just trying to compare how it's
> > loading efi differently than fatload in this case.
>
> There is nothing special about USB in boootstd, so far as I know.
>
> But until we figure out this bug, it is hard to be sure.
>
> Regards,
> Simon