Re: [PATCH 1/8] selftests: ublk: correct last_rw map type in seq_io.bt

Ming Lei
2025-12-11T08:58:19Z

On Wed, Dec 10, 2025 at 10:15:56PM -0700, Caleb Sander Mateos wrote:
> The last_rw map is initialized with a value of 0 but later assigned the
> value args.sector + args.nr_sector, which has type sector_t = u64.
> bpftrace complains about the type mismatch between int64 and uint64:
> trace/seq_io.bt:18:3-59: ERROR: Type mismatch for @last_rw: trying to assign value of type 'uint64' when map already contains a value of type 'int64'
> @last_rw[$dev, str($2)] = (args.sector + args.nr_sector);
>
> Cast the initial value to uint64 so bpftrace will load the program.
>
> Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
> ---
> tools/testing/selftests/ublk/trace/seq_io.bt | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/ublk/trace/seq_io.bt b/tools/testing/selftests/ublk/trace/seq_io.bt
> index 272ac54c9d5f..507a3ca05abf 100644
> --- a/tools/testing/selftests/ublk/trace/seq_io.bt
> +++ b/tools/testing/selftests/ublk/trace/seq_io.bt
> @@ -2,11 +2,11 @@
> $1: dev_t
> $2: RWBS
> $3: strlen($2)
> */
> BEGIN {
> - @last_rw[$1, str($2)] = 0;
> + @last_rw[$1, str($2)] = (uint64)0;

Reviewed-by: Ming Lei <ming.lei@redhat.com>

Thanks,
Ming