[PATCHv7 04/13] kexec_file: Implement decompress method for parser

[bot+bpf-ci at kernel.org]

> diff --git a/kernel/kexec_bpf_loader.c b/kernel/kexec_bpf_loader.c
> index bd1800a76782..c79fb777d51b 100644
> --- a/kernel/kexec_bpf_loader.c
> +++ b/kernel/kexec_bpf_loader.c

[ ... ]

> @@ -73,8 +74,243 @@ static int __init kexec_bpf_prog_run_init(void)
>  }
>  late_initcall(kexec_bpf_prog_run_init);

[ ... ]

>  static int kexec_buff_parser(struct bpf_parser_context *parser)
>  {
> +	struct bpf_parser_buf *pbuf = parser->buf;
> +	struct kexec_context *ctx = (struct kexec_context *)parser->data;
> +	struct cmd_hdr *cmd = (struct cmd_hdr *)pbuf->buf;
> +	char *decompressed_buf, *buf, *p;
> +	unsigned long decompressed_sz;
> +	int ret = 0;

[ ... ]

> +	case KEXEC_BPF_CMD_DECOMPRESS:
> +		ret = parser_cmd_decompress(buf, cmd->payload_len, &decompressed_buf,
> +					&decompressed_sz, ctx);
> +		if (!ret) {
> +			switch (cmd->subcmd) {
> +			case KEXEC_BPF_SUBCMD_KERNEL:
> +				vfree(ctx->kernel);
> +				ctx->kernel = decompressed_buf;
> +				ctx->kernel_sz = decompressed_sz;
> +				break;
> +			default:
> +				vfree(decompressed_buf);
> +				break;
> +			}
> +		}
> +		break;
> +	default:
> +		break;
> +	}
> +
>  	return 0;
>  }

Should this return ret instead of 0?  When parser_cmd_decompress()
fails, ret holds the error code, but the function discards it and
returns success.

bpf_buffer_parser() in bpf_buffer_parser.c propagates this return
value back to the calling BPF program:

    ret = context->func(context);
    ...
    return ret;

Returning 0 here means the BPF program sees success even when
decompression failed.  It would then proceed to send
KEXEC_BPF_CMD_DONE, setting ctx->parsed = true, causing kexec
to complete loading with a missing or undecompressed kernel image.


---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md

CI run summary: https://github.com/kernel-patches/bpf/actions/runs/23393379437