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| author | Juri Lelli <juri.lelli@redhat.com> | 2022-07-14 17:19:08 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-07-21 10:35:28 +0200 |
| commit | ddfc710395cccc61247348df9eb18ea50321cbed (patch) | |
| tree | 5087a26c67346ad80e9822b94e56cf82a833c48d | |
| parent | ff6992735ade75aae3e35d16b17da1008d753d28 (diff) | |
| download | linux-ddfc710395cccc61247348df9eb18ea50321cbed.tar.bz2 | |
sched/deadline: Fix BUG_ON condition for deboosted tasks
Tasks the are being deboosted from SCHED_DEADLINE might enter
enqueue_task_dl() one last time and hit an erroneous BUG_ON condition:
since they are not boosted anymore, the if (is_dl_boosted()) branch is
not taken, but the else if (!dl_prio) is and inside this one we
BUG_ON(!is_dl_boosted), which is of course false (BUG_ON triggered)
otherwise we had entered the if branch above. Long story short, the
current condition doesn't make sense and always leads to triggering of a
BUG.
Fix this by only checking enqueue flags, properly: ENQUEUE_REPLENISH has
to be present, but additional flags are not a problem.
Fixes: 64be6f1f5f71 ("sched/deadline: Don't replenish from a !SCHED_DEADLINE entity")
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20220714151908.533052-1-juri.lelli@redhat.com
| -rw-r--r-- | kernel/sched/deadline.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index b5152961b743..7bf561262cb8 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1701,7 +1701,10 @@ static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags) * the throttle. */ p->dl.dl_throttled = 0; - BUG_ON(!is_dl_boosted(&p->dl) || flags != ENQUEUE_REPLENISH); + if (!(flags & ENQUEUE_REPLENISH)) + printk_deferred_once("sched: DL de-boosted task PID %d: REPLENISH flag missing\n", + task_pid_nr(p)); + return; } |