On Tue, Mar 22, 2022 at 03:42:28PM +0800, Ming Lei wrote:
> > 1187 if (parent_sq) {
> > 1188 /* @parent_sq is another throl_grp, propagate dispatch */
> > 1189 if (tg->flags & THROTL_TG_WAS_EMPTY) {
> > ^^^^^^^^^
> > But the old code dereferences "tg" without checking.
>
> Here if 'parent_sq' isn't NULL, tg won't be NULL, see sq_to_tg()
>
Thanks. It would have taken me a while to find sq_to_tg(). Smatch is
supposed to figure out this stuff but somehow it's not working.
Smatch knows that if "tg" is non-NULL then parent_sq is non-NULL. And
it knows that if sq->parent_sq is NULL then tg is NULL. But somehow it
can't figure out that if sq->parent_sq is non-NULL then tg is non-NULL...
:/
Something to investigate but I ran out of time today.
regards,
dan carpenter
