sched/deadline: Initialize ->dl_boosted

syzbot reported the following warning triggered via SYSC_sched_setattr():

  WARNING: CPU: 0 PID: 6973 at kernel/sched/deadline.c:593 setup_new_dl_entity /kernel/sched/deadline.c:594 [inline]
  WARNING: CPU: 0 PID: 6973 at kernel/sched/deadline.c:593 enqueue_dl_entity /kernel/sched/deadline.c:1370 [inline]
  WARNING: CPU: 0 PID: 6973 at kernel/sched/deadline.c:593 enqueue_task_dl+0x1c17/0x2ba0 /kernel/sched/deadline.c:1441

This happens because the ->dl_boosted flag is currently not initialized by
__dl_clear_params() (unlike the other flags) and setup_new_dl_entity()
rightfully complains about it.

Initialize dl_boosted to 0.

Fixes: 2d3d891d3344 ("sched/deadline: Add SCHED_DEADLINE inheritance logic")
Reported-by: syzbot+5ac8bac25f95e8b221e7@syzkaller.appspotmail.com
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Daniel Wagner <dwagner@suse.de>
Link: https://lkml.kernel.org/r/20200617072919.818409-1-juri.lelli@redhat.com

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 504d2f5..f63f337 100644 (file)
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2692,6 +2692,7 @@ void __dl_clear_params(struct task_struct *p)
        dl_se->dl_bw                    = 0;
        dl_se->dl_density               = 0;
 
+       dl_se->dl_boosted               = 0;
        dl_se->dl_throttled             = 0;
        dl_se->dl_yielded               = 0;
        dl_se->dl_non_contending        = 0;