On Thu, Mar 14, 2019 at 8:35 AM Tim Chen <tim.c.c...@linux.intel.com> wrote: > >> > >> One more NULL pointer dereference: > >> > >> Mar 12 02:24:46 aubrey-ivb kernel: [ 201.916741] core sched enabled > >> [ 201.950203] BUG: unable to handle kernel NULL pointer dereference > >> at 0000000000000008 > >> [ 201.950254] ------------[ cut here ]------------ > >> [ 201.959045] #PF error: [normal kernel read fault] > >> [ 201.964272] !se->on_rq > >> [ 201.964287] WARNING: CPU: 22 PID: 2965 at kernel/sched/fair.c:6849 > >> set_next_buddy+0x52/0x70 > > > Shouldn't the for_each_sched_entity(se) skip the code block for !se case > have avoided null pointer access of se? > > Since > #define for_each_sched_entity(se) \ > for (; se; se = se->parent) > > Scratching my head a bit here on how your changes would have made > a difference.
This NULL pointer dereference is not replicable, which makes me thought the change works... > > In your original log, I wonder if the !se->on_rq warning on CPU 22 is mixed > with the actual OOPs? > Saw also in your original log rb_insert_color. Wonder if that > was actually the source of the Oops? No chance to figure this out, I only saw this once, lockup occurs more frequently. Thanks, -Aubrey