diff options
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/ext.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index c18e81e8ef51..9280381f8923 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -4423,10 +4423,19 @@ done: scx_bypass(false); } +/* + * Claim the exit on @sch. The caller must ensure that the helper kthread work + * is kicked before the current task can be preempted. Once exit_kind is + * claimed, scx_error() can no longer trigger, so if the current task gets + * preempted and the BPF scheduler fails to schedule it back, the helper work + * will never be kicked and the whole system can wedge. + */ static bool scx_claim_exit(struct scx_sched *sch, enum scx_exit_kind kind) { int none = SCX_EXIT_NONE; + lockdep_assert_preemption_disabled(); + if (!atomic_try_cmpxchg(&sch->exit_kind, &none, kind)) return false; @@ -4449,6 +4458,7 @@ static void scx_disable(enum scx_exit_kind kind) rcu_read_lock(); sch = rcu_dereference(scx_root); if (sch) { + guard(preempt)(); scx_claim_exit(sch, kind); kthread_queue_work(sch->helper, &sch->disable_work); } @@ -4771,6 +4781,8 @@ static bool scx_vexit(struct scx_sched *sch, { struct scx_exit_info *ei = sch->exit_info; + guard(preempt)(); + if (!scx_claim_exit(sch, kind)) return false; |