Re: [PATCH v7 05/15] LoongArch: kexec_file: Fix CMA page leaks in segment placement retry loops

[Jinjie Ruan <ruanjinjie@huawei.com>]

Will fix sashiko review issue in v8.

在 2026/10/26 15:51, Jinjie Ruan 写道:
> The retry loop drops nr_segments, leaking the CMA pages of the failed
> segments.  Release them first, and disable CMA for the retry: it
> ignores buf_min and would hand out the same region forever.
> 
> Cc: Huacai Chen <chenhuacai@kernel.org>
> Cc: WANG Xuerui <kernel@xen0n.name>
> Cc: Youling Tang <tangyouling@kylinos.cn>
> Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
> Cc: Sourabh Jain <sourabhjain@linux.ibm.com>
> Cc: Kees Cook <kees@kernel.org>
> Cc: stable@vger.kernel.org
> Link: https://sashiko.dev/#/patchset/20260729031235.2840255-1-ruanjinjie%40huawei.com
> Fixes: 55d990f0084c ("LoongArch: Add EFI binary support for kexec_file")
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
> ---
>  arch/loongarch/kernel/kexec_efi.c          | 8 ++++++++
>  arch/loongarch/kernel/machine_kexec_file.c | 6 +++++-
>  2 files changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/loongarch/kernel/kexec_efi.c b/arch/loongarch/kernel/kexec_efi.c
> index 5ee78ebb1546..d42711b895a2 100644
> --- a/arch/loongarch/kernel/kexec_efi.c
> +++ b/arch/loongarch/kernel/kexec_efi.c
> @@ -86,6 +86,14 @@ static void *efi_kexec_load(struct kimage *image,
>  		 * We couldn't find space for the other segments; erase the
>  		 * kernel segment and try the next available hole.
>  		 */
> +		/*
> +		 * kexec_alloc_contig() ignores buf_min, so disable CMA to
> +		 * let the retry make progress.
> +		 */
> +		if (image->segment_cma[kernel_segment_number])
> +			image->no_cma = true;
> +
> +		kexec_free_segment_cma(image, kernel_segment_number);
>  		image->nr_segments -= 1;
>  		kbuf.buf_min = kernel_segment->mem + kernel_segment->memsz;
>  		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
> diff --git a/arch/loongarch/kernel/machine_kexec_file.c b/arch/loongarch/kernel/machine_kexec_file.c
> index 5412aa9f3568..62a5be102065 100644
> --- a/arch/loongarch/kernel/machine_kexec_file.c
> +++ b/arch/loongarch/kernel/machine_kexec_file.c
> @@ -217,7 +217,11 @@ int load_other_segments(struct kimage *image,
>  	return 0;
>  
>  out_err:
> -	image->nr_segments = orig_segments;
> +	while (image->nr_segments > orig_segments) {
> +		kexec_free_segment_cma(image, image->nr_segments - 1);
> +		image->nr_segments--;
> +	}
> +
>  	kfree(modified_cmdline);
>  	return ret;
>  }

-- 
Best regards,
Jinjie