On Mon, Nov 11, 2019 at 11:21:15PM +0000, John Levon wrote:
>
> Given:
>
> enum ib_qp_state {
> IB_QPS_RESET,
> IB_QPS_INIT,
> IB_QPS_RTR,
> IB_QPS_RTS,
> IB_QPS_SQD,
> IB_QPS_SQE,
> IB_QPS_ERR
> };
>
> int p(enum ib_qp_state cur_state, enum ib_qp_state next_state)
> {
> #if 0
> if (cur_state < 0 || cur_state > IB_QPS_ERR ||
> next_state < 0 || next_state > IB_QPS_ERR) {
> return (5);
> }
> #else
> if (next_state < 0 || next_state > IB_QPS_ERR) {
> return (5);
> }
> #endif
>
> return (0);
> }
>
> current smatch is happy. But "#if 1" above instead, and:
>
> jlevon@sent:~/src/smatch$ ./smatch a.c
> ./smatch: a.c:15 p() warn: unsigned 'cur_state' is never less than zero.
>
> Why is "next_state" not reported equally?
My plan was that neither one would print a warning. When people do
if (foo < 0 || foo > max)
then normally it's not a real life bug... Linus said at kernel summit
that he doesn't like when people send patches for those.
The problem is that when I wrote the code to silence the warning then I
hadn't created all the expr_get_parent_expr() function so I couldn't
silence it properly.
regards,
dan carpenter
