Re: [PATCH] kexec: return -ENOEXEC from image probe functions on mismatch

Hi Mukesh,

the patch looks good to me.

There is also a corresponding kexec-tools patch, which was accidentally
opened as a Github PR (https://github.com/horms/kexec-tools/pull/12).
It will be sent to [email protected] shortly.

Thanks

Reviewed-by: Philipp Rudo <[email protected]>

On Thu, 13 Aug 2026 12:36:29 +0530
Mukesh Pilaniya <[email protected]> wrote:

> Several kexec_file_load() image probe functions return -EINVAL when
> they do not recognize the image format.  A probe function that rejects
> an image should return -ENOEXEC to indicate that the image is not a
> recognized executable format.  -EINVAL implies a problem with the
> syscall parameters, not with image recognition.
> 
> kexec_image_probe_default() iterates through registered loaders and
> returns the last probe's error code to the caller.  That error
> propagates as the kexec_file_load() return value to userspace.
> Returning -EINVAL from a probe when no loader matches is semantically
> incorrect and misleads userspace about the nature of the failure.
> 
> Return -ENOEXEC from all probe functions and their helpers when the
> image format is not recognized.
> 
> Signed-off-by: Mukesh Pilaniya <[email protected]>
> ---
> branch: next-20260812
> base commit: 28d012efb4327f9c75d5e042a7c91e9a542efa98
> ---
>  arch/arm64/kernel/kexec_image.c   | 4 ++--
>  arch/loongarch/kernel/kexec_efi.c | 4 ++--
>  arch/riscv/kernel/kexec_image.c   | 4 ++--
>  kernel/kexec_elf.c                | 4 ++--
>  4 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c
> index b70f4df15a1a..101259874d44 100644
> --- a/arch/arm64/kernel/kexec_image.c
> +++ b/arch/arm64/kernel/kexec_image.c
> @@ -25,10 +25,10 @@ static int image_probe(const char *kernel_buf, unsigned long kernel_len)
>  		(const struct arm64_image_header *)(kernel_buf);
>  
>  	if (!h || (kernel_len < sizeof(*h)))
> -		return -EINVAL;
> +		return -ENOEXEC;
>  
>  	if (memcmp(&h->magic, ARM64_IMAGE_MAGIC, sizeof(h->magic)))
> -		return -EINVAL;
> +		return -ENOEXEC;
>  
>  	return 0;
>  }
> diff --git a/arch/loongarch/kernel/kexec_efi.c b/arch/loongarch/kernel/kexec_efi.c
> index 5ee78ebb1546..28a1d0420ba3 100644
> --- a/arch/loongarch/kernel/kexec_efi.c
> +++ b/arch/loongarch/kernel/kexec_efi.c
> @@ -24,12 +24,12 @@ static int efi_kexec_probe(const char *kernel_buf, unsigned long kernel_len)
>  
>  	if (!h || (kernel_len < sizeof(*h))) {
>  		kexec_dprintk("No LoongArch image header.\n");
> -		return -EINVAL;
> +		return -ENOEXEC;
>  	}
>  
>  	if (!loongarch_header_check_dos_sig(h)) {
>  		kexec_dprintk("No LoongArch PE image header.\n");
> -		return -EINVAL;
> +		return -ENOEXEC;
>  	}
>  
>  	return 0;
> diff --git a/arch/riscv/kernel/kexec_image.c b/arch/riscv/kernel/kexec_image.c
> index 51dc89259f16..963a25f5b55b 100644
> --- a/arch/riscv/kernel/kexec_image.c
> +++ b/arch/riscv/kernel/kexec_image.c
> @@ -20,7 +20,7 @@ static int image_probe(const char *kernel_buf, unsigned long kernel_len)
>  	const struct riscv_image_header *h = (const struct riscv_image_header *)kernel_buf;
>  
>  	if (!h || kernel_len < sizeof(*h))
> -		return -EINVAL;
> +		return -ENOEXEC;
>  
>  	/* According to Documentation/arch/riscv/boot-image-header.rst,
>  	 * use "magic2" field to check when version >= 0.2.
> @@ -28,7 +28,7 @@ static int image_probe(const char *kernel_buf, unsigned long kernel_len)
>  
>  	if (h->version >= RISCV_HEADER_VERSION &&
>  	    memcmp(&h->magic2, RISCV_IMAGE_MAGIC2, sizeof(h->magic2)))
> -		return -EINVAL;
> +		return -ENOEXEC;
>  
>  	return 0;
>  }
> diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c
> index 3a5c25b2adc9..89a444a00693 100644
> --- a/kernel/kexec_elf.c
> +++ b/kernel/kexec_elf.c
> @@ -172,7 +172,7 @@ static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr)
>  
>  	default:
>  		pr_debug("Unknown ELF class.\n");
> -		return -EINVAL;
> +		return -ENOEXEC;
>  	}
>  
>  	return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC;
> @@ -236,7 +236,7 @@ static int elf_read_phdr(const char *buf, size_t len,
>  
>  	default:
>  		pr_debug("Unknown ELF class.\n");
> -		return -EINVAL;
> +		return -ENOEXEC;
>  	}
>  
>  	return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC;
> 
> ---
> base-commit: 28d012efb4327f9c75d5e042a7c91e9a542efa98
> change-id: 20260813-mpilaniy-ffb0cc92c313
> 
> Best regards,
> --  
> Mukesh Pilaniya <[email protected]>
>