Re: [Buildroot] [PATCH 1/6] configs/stm32f429_disco_xip: fix boot failure after uClibc bump

Hi Dario,

On 21/07/2026 20:42, Dario Binacchi wrote:
> Since uClibc was bumped to 1.0.58 (c7fef3704c70, "package/uclibc:
> bump to 1.0.58"), the board fails to boot:
> 
>     sh: out of memory
>     Kernel panic - not syncing: Attempted to kill init! 
> exitcode=0x00000100
>     CPU: 0 PID: 1 Comm: init Not tainted 6.1.167 #2
>     Hardware name: STM32 (Device Tree Support)
>     Function entered at [<0800ea1e>] from [<0800de7b>]
>     Function entered at [<0800de7b>] from [<080e4991>]
>     Function entered at [<080e4991>] from [<080e2d19>]
>     Function entered at [<080e2d19>] from [<080125eb>]
>     Function entered at [<080125eb>] from [<08012b09>]
>     Function entered at [<08012b09>] from [<08012b69>]
>     ---[ end Kernel panic - not syncing: Attempted to kill init! 
> exitcode=0x00000100 ]---
> 
> The STM32F429 has no MMU, and uClibc's standard malloc() implementation
> returns NULL for allocations performed during early init on this 
> target,
> causing init to abort immediately.
> 
> Fix this by switching to MALLOC_SIMPLE, a plain mmap-based allocator
> meant for small/noMMU systems, via a uClibc config fragment. The
> fragment is placed under board/stmicroelectronics/common/stm32f4xx/,
> rather than under the board-specific directory, so that it can be
> shared with the STM32F469, another Cortex-M4/noMMU board affected by
> the same issue, which will be fixed in a subsequent patch.

For info, the issue may have been introduced by uclibc commit:
https://github.com/wbx-github/uclibc-ng/commit/487af14988c3c923aa661f204642597cff356a83

There is an upstream fix, not released yet,  which seems to fix the 
issue:
https://github.com/wbx-github/uclibc-ng/commit/7730f0d05a51cd89a7123bd696e4638c3c035d7b

You could possibly drop this malloc config change after the next uclibc 
bump.

> Signed-off-by: Dario Binacchi <[email protected]>

In the meantime, I applied this series to master, thanks.

> ---
>  .../stmicroelectronics/common/stm32f4xx/uclibc-fragment.config  | 2 ++
>  configs/stm32f429_disco_xip_defconfig                           | 1 +
>  2 files changed, 3 insertions(+)
>  create mode 100644 
> board/stmicroelectronics/common/stm32f4xx/uclibc-fragment.config
> 
> diff --git 
> a/board/stmicroelectronics/common/stm32f4xx/uclibc-fragment.config 
> b/board/stmicroelectronics/common/stm32f4xx/uclibc-fragment.config
> new file mode 100644
> index 000000000000..fb8fa9ee01c3
> --- /dev/null
> +++ b/board/stmicroelectronics/common/stm32f4xx/uclibc-fragment.config
> @@ -0,0 +1,2 @@
> +# MALLOC is not set
> +MALLOC_SIMPLE=y
> diff --git a/configs/stm32f429_disco_xip_defconfig 
> b/configs/stm32f429_disco_xip_defconfig
> index 489303b93e0d..e6edfa906177 100644
> --- a/configs/stm32f429_disco_xip_defconfig
> +++ b/configs/stm32f429_disco_xip_defconfig
> @@ -1,6 +1,7 @@
>  BR2_arm=y
>  BR2_cortex_m4=y
>  BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_6_1=y
> +BR2_UCLIBC_CONFIG_FRAGMENT_FILES="board/stmicroelectronics/common/stm32f4xx/uclibc-fragment.config"
>  # BR2_UCLIBC_INSTALL_UTILS is not set
>  BR2_ENABLE_LTO=y
>  
> BR2_GLOBAL_PATCH_DIR="board/stmicroelectronics/stm32f429-disco/patches"
> --
> 2.43.0

Best regards,

Julien.
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