Re: [PATCH v2 1/1] bootm: improve error message when gzip decompression buffer is too small

[Mattijs Korpershoek <mkorpershoek@kernel.org>]

Hi Aristo,

Thank you for the patch.

On mer., avril 30, 2025 at 10:23, Aristo Chen <jj251510319013@gmail.com> wrote:

> Currently, when decompressing a gzip-compressed image during bootm, a
> generic error such as "inflate() returned -5" is shown when the buffer is
> too small. However, it is not immediately clear that this is caused by
> CONFIG_SYS_BOOTM_LEN being too small.
>
> This patch improves error handling by:
> - Detecting Z_BUF_ERROR (-5) returned from the inflate() call
> - Suggesting the user to increase CONFIG_SYS_BOOTM_LEN when applicable
> - Preserving the original return code from zunzip() instead of overwriting
>   it with -1
>
> By providing clearer hints when decompression fails due to insufficient
> buffer size, this change helps users diagnose and fix boot failures more
> easily.
>
> Signed-off-by: Aristo Chen <aristo.chen@canonical.com>

Reviewed-by: Mattijs Korpershoek <mkorpershoek@kernel.org>

> ---
>  boot/bootm.c | 4 +++-
>  lib/gunzip.c | 2 +-
>  2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/boot/bootm.c b/boot/bootm.c
> index f5cbb10f0d1..f6aa32746b7 100644
> --- a/boot/bootm.c
> +++ b/boot/bootm.c
> @@ -34,6 +34,7 @@
>  
>  #include <bootm.h>
>  #include <image.h>
> +#include <u-boot/zlib.h>
>  
>  #define MAX_CMDLINE_SIZE	SZ_4K
>  
> @@ -578,7 +579,8 @@ static int handle_decomp_error(int comp_type, size_t uncomp_size,
>  	if (ret == -ENOSYS)
>  		return BOOTM_ERR_UNIMPLEMENTED;
>  
> -	if (uncomp_size >= buf_size)
> +	if ((comp_type == IH_COMP_GZIP && ret == Z_BUF_ERROR) ||
> +	    uncomp_size >= buf_size)
>  		printf("Image too large: increase CONFIG_SYS_BOOTM_LEN\n");
>  	else
>  		printf("%s: uncompress error %d\n", name, ret);
> diff --git a/lib/gunzip.c b/lib/gunzip.c
> index 52007715bda..a05dcde9a75 100644
> --- a/lib/gunzip.c
> +++ b/lib/gunzip.c
> @@ -299,7 +299,7 @@ __rcode int zunzip(void *dst, int dstlen, unsigned char *src,
>  		if (stoponerr == 1 && r != Z_STREAM_END &&
>  		    (s.avail_in == 0 || s.avail_out == 0 || r != Z_BUF_ERROR)) {
>  			printf("Error: inflate() returned %d\n", r);
> -			err = -1;
> +			err = r;
>  			break;
>  		}
>  	} while (r == Z_BUF_ERROR);
> -- 
> 2.34.1