Re: [PATCH v7 03/15] arm64: kexec_file: Fix CMA page leaks in segment placement retry loops

[Jinjie Ruan]

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: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Cc: Breno Leitao <leitao@xxxxxxxxxx>
> Cc: Pratyush Yadav <pratyush@xxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Yeoreum Yun <yeoreum.yun@xxxxxxx>
> Cc: Baoquan He <bhe@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 07d24902977e ("kexec: enable CMA based contiguous allocation")
> Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
> ---
>  arch/arm64/kernel/kexec_image.c        | 8 ++++++++
>  arch/arm64/kernel/machine_kexec_file.c | 5 ++++-
>  2 files changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c
> index 74d24c8aa2fa..6ed1991e3142 100644
> --- a/arch/arm64/kernel/kexec_image.c
> +++ b/arch/arm64/kernel/kexec_image.c
> @@ -111,6 +111,14 @@ static void *image_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/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
> index 854d872dfd0f..e48f29167b38 100644
> --- a/arch/arm64/kernel/machine_kexec_file.c
> +++ b/arch/arm64/kernel/machine_kexec_file.c
> @@ -179,7 +179,10 @@ 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--;
> +	}
>  	kvfree(dtb);
>  	return ret;
>  }

-- 
Best regards,
Jinjie