On Tue, Jul 19, 2022 at 12:49:34PM +0300, Dan Carpenter wrote:
> The code here is supposed to take a signed int and store it in a
> signed long long. Unfortunately, the way that the type promotion works
> with this conditional statement is that it takes a signed int, type
> promotes it to a __u32, and then stores that as a signed long long.
> The result is never negative.
>
> Fixes: d90ec262b35b ("libbpf: Add enum64 support for btf_dump")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
> tools/lib/bpf/btf_dump.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
> index 400e84fd0578..627edb5bb6de 100644
> --- a/tools/lib/bpf/btf_dump.c
> +++ b/tools/lib/bpf/btf_dump.c
> @@ -2045,7 +2045,7 @@ static int btf_dump_get_enum_value(struct btf_dump *d,
> *value = *(__s64 *)data;
> return 0;
> case 4:
> - *value = is_signed ? *(__s32 *)data : *(__u32 *)data;
> + *value = is_signed ? (__s64)*(__s32 *)data : *(__u32 *)data;
Only case 4 has issues and what does the standard say ?
Do you have a sample dump to debug this that can be pasted in the commit log?
> return 0;
> case 2:
> *value = is_signed ? *(__s16 *)data : *(__u16 *)data;
> --
> 2.35.1
>
