On Mon, Nov 18, 2019 at 08:03:09AM +0100, Heinrich Schuchardt wrote:
> With GCC 9.2.1 '-FDT_ERRTABSIZE' is of type long unsigned int so it is
> always a positive number.
>
> This becomes easily visible when adding -Wextra to the compiler flags:
>
> libfdt/fdt_strerror.c:51:18: warning: comparison of integer expressions
> of different signedness: ‘int’ and ‘long unsigned int’ [-Wsign-compare]
> 51 | else if (errval > -FDT_ERRTABSIZE) {
>
> So (errval > -FDT_ERRTABSIZE) is always false in contrast to what the
> developer intended.
>
> Add the missing type conversion.
>
> Signed-off-by: Heinrich Schuchardt <xypron.glpk@xxxxxx>
I'd prefer to have the cast in the definition of FDT_ERRTABSIZE.
Throughout libfdt, error values are generally treated as being (int),
so that's the likely type this value is going to be compared with
everywhere, not just here.
> ---
> It would be advisable to add -Wextra to the Makefile after correcting
> the 50+ -Wsign-compare problems reported.
> ---
> libfdt/fdt_strerror.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libfdt/fdt_strerror.c b/libfdt/fdt_strerror.c
> index 768db66..c02c6ef 100644
> --- a/libfdt/fdt_strerror.c
> +++ b/libfdt/fdt_strerror.c
> @@ -48,7 +48,7 @@ const char *fdt_strerror(int errval)
> return "<valid offset/length>";
> else if (errval == 0)
> return "<no error>";
> - else if (errval > -FDT_ERRTABSIZE) {
> + else if (errval > (int)-FDT_ERRTABSIZE) {
> const char *s = fdt_errtable[-errval].str;
>
> if (s)
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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