> On Apr 22, 2019, at 12:36 PM, Cong Wang <xiyou.wangc...@gmail.com> wrote: > > On Mon, Apr 22, 2019 at 12:24 PM Guedes, Andre <andre.gue...@intel.com> wrote: >> >> >>> On Apr 22, 2019, at 11:07 AM, Cong Wang <xiyou.wangc...@gmail.com> wrote: >>> >>> On Mon, Apr 22, 2019 at 11:04 AM Cong Wang <xiyou.wangc...@gmail.com> wrote: >>>> >>>> On Fri, Apr 19, 2019 at 6:06 PM Andre Guedes <andre.gue...@intel.com> >>>> wrote: >>>>> >>>>> If 'entry' is NULL we WARN_ON() but dereference the pointer anyway, >>>>> generating a null pointer dereference bug. This patch fixes should_ >>>>> restart_cycle() so we return if the pointer is NULL. >>>> >>>> Hmm, while you are on it, how is it possible to have entry==NULL >>>> for should_restart_cycle(). It is only called in advance_sched() >>>> where entry is already checked against NULL right before it, >>>> so for me, entry is always NULL at the point of calling >>>> should_restart_cycle(). >>> >>> I meant, 'entry' is always non-NULL here... I typed too fast. >> >> Your assessment is correct. I believe the WARN_ON() was added as a defensive >> practice to prevent null pointer dereference in case someone misuse that >> helper in the future. > > Yeah, so we can just remove it. :)
Fine by me. In that case, the function should_restart_cycle() will be just a dummy wrapper on list_is_last() so we should probably get rid of it and call list_is_last() within advance_sched().
