On Tue, Mar 16, 2021 at 10:05 AM Ryan Harper <1918...@bugs.launchpad.net> wrote: > > Hi Dan, > > Could you summarize the problem with flash-kernel and this system?
Sure. flash-kernel recognizes Mustang boards and will generate uImage and uInitrd files for it, which are required for booting with u-boot firmware. However, these boards can also run in UEFI mode, which Date's board does. In UEFI mode, flash-kernel still knows it is on a Mustang and generates uImage/uInitrd files - which won't be used for anything in that case, they are just wasting space, but does not cause it to fail. This does cause problems in a curtin install though. Curtin has logic to divert away tools that get executed during initramfs hooks, to avoid failures in packaging scripts before an initramfs is generated. flash-kernel in particular will fail if an initramfs is not found on this system. Curtin tries to be smart here and only divert flash-kernel 1) if it is installed and 2) on systems that are*not* in UEFI mode, and both of these scenarios have escapes: 1) flash-kernel could get installed post-divert. In that case, flash-kernel's own postinst will cause it to run and then fail. This happens today if you start with a cloud image w/o flash-kernel pre-baked because Ubuntu's kernel recommends flash-kernel, causing it to be installed along with the kernel. Official cloud images happen to have flash-kernel pre-baked which avoids this issue. I think curtin should work whether or not the kernel recommends flash-kernel and whether or not curtin is pre-baked (in fact, I'd like for us to stop pre-baking it - the vast majoriy of ARM servers do not need it). 2) If flash-kernel is installed, and curtin finds we're in UEFI mode, it chooses not to divert flash-kernel. flash-kernel will therefore run and fail on UEFI Mustangs. The way I've personally framed this issue is that Ubuntu should not be trying to install flash-kernel on ARM systems that don't require it, which is the reason I've added the various tasks here. - cloud images shouldn't prebake it - the kernel should allow non-flash-kernel bootloaders to satisfy its recommends - curtin shouldn't install flash-kernel on efi-based arm64 servers. It does this today, but - in what seems like a bug, only in the ephemeral and not the target. A separate issue is that flash-kernel should know to just exit if it's running on an EFI system and not bother creating the unused uImage/uInitrd - Date recently got a patched merged into Debian's f-k to do that. That would seemingly also avoid the curtin issues here, but only if we continue to install flash-kernel all the time. -dann -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1918427 Title: curtin: install flash-kernel in arm64 UEFI unexpected Status in cloud-images: Confirmed Status in curtin package in Ubuntu: Confirmed Status in linux package in Ubuntu: In Progress Bug description: I used APM Mustang which flash-kernel supported in u-boot mode. But I used it with UEFI environment. It will cause fatal error when I used ARM64 ubuntu live server ISO to install system. In code[1], this will not install `flash-kernel` for APM Mustang because of UEFI. So that means code[2] will not disable `flash-kernel` in target system, only disable `update-initramfs`. When curtin execute to `install_kernel` stage, code[3,4] will not install `flash-kernel` either. But in code[5], it will install `linux-generic`. `linux-generic` has a long dependency tree and it will get `flash-kernel` in Recommended field. Apt by default will install Recommended package before kernel is installed.[6] So it will still execute `zz-flash-kernel` and `flash-kernel` when installing kernel. But system didn't create any `initrd.img` ever because curtin disable `update-initramfs` in code[2]. This will cause that `flash-kernel` cannot find `initrd.img.<kvers>` and fail when installing it. This issue didn't effect all ARM64 UEFI platform because `flash-kernel` didn't support them and skip.[7] I'm not sure which is best solution for this. But I think we should apply PR-27 in `flash-kernel`[8] for enhancement and fix curtin process with this patch both. If we only apply PR-27, it should work fine as well because it will be skipped when detecting UEFI and install `flash-kernel` before `disable_update_initranfs` in ARM platform without UEFI.[9] [Patch-1,2,3] might have side effect. Picking one patch for curtin should be enough. But I need your advice for this to determine which one is better for curtin. There are two categories 1. avoid installing flash-kernel if no need, [Patch1,2] 2. always install flash-kernel in arm/arm64 and make sure it be installed before code[2] [Patch3] (I will attach patch in reply.) Thanks a lot Regards, Date [1] https://github.com/canonical/curtin/blob/master/curtin/deps/__init__.py#L57-L58 [2] https://github.com/canonical/curtin/blob/master/curtin/commands/curthooks.py#L1693-L1699 [3] https://github.com/canonical/curtin/blob/master/curtin/commands/curthooks.py#L365-L370 [4] https://github.com/canonical/curtin/blob/master/curtin/commands/curthooks.py#L311-L327 [5] https://github.com/canonical/curtin/blob/master/curtin/commands/curthooks.py#L372-L374 [6] https://github.com/Debian/apt/blob/master/apt-pkg/init.cc#L132 [7] https://salsa.debian.org/installer-team/flash-kernel/-/blob/master/functions#L787 [8] https://salsa.debian.org/installer-team/flash-kernel/-/merge_requests/27 [9] curtin will insert `flash-kernel` into `REQUIRED_EXECUTABLES` when system is arm/arm64 without UEFI. 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