Re: [PATCH v2] qemuarm-trixie: Workaround with missing drivers in qemuarm-trixie initramfs

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

On 20.02.26 15:42, Zhihang Wei wrote:
> This is a workaround to fix the current qemuarm-trixie image unbootable
> issue.
> 
> 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, required modules such as virtio_blk are not detected and not
> added to the initramfs. The produced image then fails to boot under
> qemu because the block device driver is missing.
> 
> 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>
> ---
> Changes in v2:
> - Use initramfs-hook to install the driver, instead of adding another
>   variable
> 
>  meta-isar/conf/multiconfig/qemuarm-trixie.conf            | 4 +++-
>  .../initramfs-virtio-blk-hook_0.1.bb                      | 8 ++++++++
>  2 files changed, 11 insertions(+), 1 deletion(-)
>  create mode 100644 meta/recipes-initramfs/initramfs-virtio-blk-hook/initramfs-virtio-blk-hook_0.1.bb
> 
> diff --git a/meta-isar/conf/multiconfig/qemuarm-trixie.conf b/meta-isar/conf/multiconfig/qemuarm-trixie.conf
> index 5600ab23..20eecd92 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-virtio-blk-hook"

This covers the initramfs-tools based generation. What if someone
enables dracut (kas/opt/dracut.yaml)?

> diff --git a/meta/recipes-initramfs/initramfs-virtio-blk-hook/initramfs-virtio-blk-hook_0.1.bb b/meta/recipes-initramfs/initramfs-virtio-blk-hook/initramfs-virtio-blk-hook_0.1.bb
> new file mode 100644
> index 00000000..229d91d6
> --- /dev/null
> +++ b/meta/recipes-initramfs/initramfs-virtio-blk-hook/initramfs-virtio-blk-hook_0.1.bb
> @@ -0,0 +1,8 @@
> +# This software is a part of Isar.
> +# Copyright (C) 2026 ilbers GmbH
> +#
> +# SPDX-License-Identifier: MIT
> +
> +inherit initramfs-hook
> +
> +HOOK_ADD_MODULES = "virtio-blk"

Jan

-- 
Siemens AG, Foundational Technologies
Linux Expert Center

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