On Sun, Mar 17, 2019 at 12:11:14PM +0200, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@xxxxxxxxxxxx>
>
> Attempt to use check_shl_overflow() with inputs of unsigned type
> produces the following compilation warnings.
>
> drivers/infiniband/hw/mlx5/qp.c: In function _set_user_rq_size_:
> ./include/linux/overflow.h:230:6: warning: comparison of unsigned
> expression >= 0 is always true [-Wtype-limits]
> _s >= 0 && _s < 8 * sizeof(*d) ? _s : 0; \
> ^~
> drivers/infiniband/hw/mlx5/qp.c:5820:6: note: in expansion of macro _check_shl_overflow_
> if (check_shl_overflow(rwq->wqe_count, rwq->wqe_shift,
> &rwq->buf_size))
> ^~~~~~~~~~~~~~~~~~
> ./include/linux/overflow.h:232:26: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits]
> (_to_shift != _s || *_d < 0 || _a < 0 || \
> ^
> drivers/infiniband/hw/mlx5/qp.c:5820:6: note: in expansion of macro _check_shl_overflow_
> if (check_shl_overflow(rwq->wqe_count, rwq->wqe_shift, &rwq->buf_size))
> ^~~~~~~~~~~~~~~~~~
> ./include/linux/overflow.h:232:36: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits]
> (_to_shift != _s || *_d < 0 || _a < 0 || \
> ^
> drivers/infiniband/hw/mlx5/qp.c:5820:6: note: in expansion of macro _check_shl_overflow_
> if (check_shl_overflow(rwq->wqe_count, rwq->wqe_shift,&rwq->buf_size))
> ^~~~~~~~~~~~~~~~~~
>
> Fixes: 0c66847793d1 ("overflow.h: Add arithmetic shift helper")
> Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
> Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
> Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
> ---
> Changelog:
> v2->v3:
> * Change _s to be is_non_negative() too.
> v1->v2:
> * Added Bart's and Kees's tags
> * Added is_negative()/is_non_negative() macro as Rasmus suggested
> v0->v1:
> * Fixed wrong checks
> ---
> include/linux/overflow.h | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
Applied to for-next
Thanks,
Jason
