Re: [PATCH v3] trixie: Workaround with missing drivers in initramfs

["'Jan Kiszka' via isar-users" <isar-users@googlegroups.com>]

On 04.03.26 17:47, Zhihang Wei wrote:
> This is a workaround for the booting issue on several Trixie
> targets, which is caused by missing drivers in their initramfs.
> 
> Starting with Debian Trixie, update-initramfs invokes "dracut-install"
> to collect and install required drivers into the generated initramfs.
> "dracut-install" relies on fts_open() / fts_read() from glibc to
> traverse directories and locate drivers.
> 
> Due to a long-standing bug [1] between qemu and glibc, the fts_*
> functions may fail to find files on certain 32-bit architectures. As a
> result, some required modules are not detected and not added to the
> initramfs. The produced image then fails to boot.
> It's known that at least these targets under Trixie are affected:
> - qemuarm (missing virtio_blk)
> - bananapi (missing sunxi_mmc)
> - nanopi-neo (missing sunxi_mmc)
> 
> A similiar dracut bug report was filed in 2024 [2], pointing to this
> upstream glibc issue reported in 2018 [1]. No upstream fix has been
> applied, and the issue appears to affect only qemu builds for specific
> 32-bit targets.
> 
> As a temporary workaround, use a customized initramfs-hook to append
> the neccessary drivers that are currently missed from the initramfs.
> 
> For a complete fix, we either need to push for an upstream glibc/qemu
> fix, or convince dracut to avoid using these non-POSIX fts_* functions
> and use opendir() / readdir() instead.
> 
> [1] https://sourceware.org/bugzilla/show_bug.cgi?id=23960
> [2] https://bugs-devel.debian.org/cgi-bin/bugreport.cgi?bug=1079443
> 
> Signed-off-by: Zhihang Wei <wzh@ilbers.de>
> ---
> 
> To apply this patch, the DTB patch and the "Add Trixie support for
> various machines" patch are needed.
> 
>  .../conf/multiconfig/bananapi-trixie.conf     |  2 +
>  .../conf/multiconfig/nanopi-neo-trixie.conf   |  2 +
>  .../conf/multiconfig/qemuarm-trixie.conf      |  4 +-
>  .../initramfs-trixie-armhf-hook_0.1.bb        | 50 +++++++++++++++++++
>  4 files changed, 57 insertions(+), 1 deletion(-)
>  create mode 100644 meta/recipes-initramfs/initramfs-trixie-armhf-hook/initramfs-trixie-armhf-hook_0.1.bb
> 
> diff --git a/meta-isar/conf/multiconfig/bananapi-trixie.conf b/meta-isar/conf/multiconfig/bananapi-trixie.conf
> index 66f9db89..c2a9c667 100644
> --- a/meta-isar/conf/multiconfig/bananapi-trixie.conf
> +++ b/meta-isar/conf/multiconfig/bananapi-trixie.conf
> @@ -3,3 +3,5 @@
>  
>  MACHINE ?= "bananapi"
>  DISTRO ?= "debian-trixie"
> +
> +IMAGE_INSTALL += "initramfs-trixie-armhf-hook"
> diff --git a/meta-isar/conf/multiconfig/nanopi-neo-trixie.conf b/meta-isar/conf/multiconfig/nanopi-neo-trixie.conf
> index 6e8f8a44..ee53e68d 100644
> --- a/meta-isar/conf/multiconfig/nanopi-neo-trixie.conf
> +++ b/meta-isar/conf/multiconfig/nanopi-neo-trixie.conf
> @@ -3,3 +3,5 @@
>  
>  MACHINE ?= "nanopi-neo"
>  DISTRO ?= "debian-trixie"
> +
> +IMAGE_INSTALL += "initramfs-trixie-armhf-hook"
> diff --git a/meta-isar/conf/multiconfig/qemuarm-trixie.conf b/meta-isar/conf/multiconfig/qemuarm-trixie.conf
> index 5600ab23..5ec903a5 100644
> --- a/meta-isar/conf/multiconfig/qemuarm-trixie.conf
> +++ b/meta-isar/conf/multiconfig/qemuarm-trixie.conf
> @@ -1,7 +1,9 @@
>  # This software is a part of Isar.
> -# Copyright (C) 2024 ilbers GmbH
> +# Copyright (C) 2024-2026 ilbers GmbH
>  #
>  # SPDX-License-Identifier: MIT
>  
>  MACHINE ?= "qemuarm"
>  DISTRO ?= "debian-trixie"
> +
> +IMAGE_INSTALL += "initramfs-trixie-armhf-hook"
> diff --git a/meta/recipes-initramfs/initramfs-trixie-armhf-hook/initramfs-trixie-armhf-hook_0.1.bb b/meta/recipes-initramfs/initramfs-trixie-armhf-hook/initramfs-trixie-armhf-hook_0.1.bb
> new file mode 100644
> index 00000000..dc923e9f
> --- /dev/null
> +++ b/meta/recipes-initramfs/initramfs-trixie-armhf-hook/initramfs-trixie-armhf-hook_0.1.bb

meta-isar/, please - you are referring to machines here which are not
known to meta/.

> @@ -0,0 +1,50 @@
> +# This software is a part of Isar.
> +# Copyright (C) 2026 ilbers GmbH
> +#
> +# SPDX-License-Identifier: MIT
> +
> +MAINTAINER = "isar-users <isar-users@googlegroups.com>"
> +
> +inherit initramfs-hook
> +
> +# -----------------------------------------------------------------------------
> +# This recipe serves as an example workaround to add missing drivers to
> +# the initramfs generated for Debian Trixie. The drivers are missing due
> +# to an upstream bug in glibc/qemu. This issue caused booting issue on
> +# several Trixie targets.
> +#
> +# Background:
> +#
> +# Starting with Debian Trixie, update-initramfs invokes "dracut-install"
> +# to collect and install required drivers into the generated initramfs.
> +# "dracut-install" relies on fts_open() / fts_read() from glibc to
> +# traverse directories and locate drivers.
> +#
> +# Due to a long-standing bug [1] between qemu and glibc, the fts_*
> +# functions may fail to find files on certain 32-bit architectures. As a
> +# result, some required modules are not detected and not added to the
> +# initramfs. The produced image then fails to boot.
> +#
> +# It's known that at least these targets under Trixie are affected: 
> +# - qemuarm (missing virtio_blk)
> +# - bananapi (missing sunxi_mmc)
> +# - nanopi-neo (missing sunxi_mmc)
> +#
> +# A similiar dracut bug report was filed in 2024 [2], pointing to this
> +# upstream glibc issue reported in 2018 [1]. No upstream fix has been
> +# applied, and the issue appears to affect only qemu builds for specific
> +# 32-bit targets.
> +#
> +# [1] https://sourceware.org/bugzilla/show_bug.cgi?id=23960
> +# [2] https://bugs-devel.debian.org/cgi-bin/bugreport.cgi?bug=1079443
> +#
> +# Purpose of this recipe:
> +#
> +# This recipe provides a temporary workaround by using a customized
> +# initramfs hook to append drivers that are currently missing from
> +# the initramfs, allowing the target to boot.
> +# -----------------------------------------------------------------------------
> +
> +HOOK_ADD_MODULES:append:qemuarm:debian-trixie = "virtio-blk"
> +HOOK_ADD_MODULES:append:bananapi:debian-trixie = "sunxi_mmc"
> +HOOK_ADD_MODULES:append:nanopi-neo:debian-trixie = "sunxi_mmc"

So, we are ignoring the dracut-native initramfs case. Please document
that at least because users can still configure that.

Jan

-- 
Siemens AG, Foundational Technologies
Linux Expert Center

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