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| author | Pietro Borrello <borrello@diag.uniroma1.it> | 2023-02-06 23:33:54 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2023-02-11 11:18:10 +0100 |
| commit | 7c4a5b89a0b5a57a64b601775b296abf77a9fe97 (patch) | |
| tree | f8dc5bdfda4b3a335fc05b9d6ea4e36ae442455e /kernel/sched | |
| parent | sched/deadline: Add more reschedule cases to prio_changed_dl() (diff) | |
| download | linux-7c4a5b89a0b5a57a64b601775b296abf77a9fe97.tar.xz linux-7c4a5b89a0b5a57a64b601775b296abf77a9fe97.zip | |
sched/rt: pick_next_rt_entity(): check list_entry
Commit 326587b84078 ("sched: fix goto retry in pick_next_task_rt()")
removed any path which could make pick_next_rt_entity() return NULL.
However, BUG_ON(!rt_se) in _pick_next_task_rt() (the only caller of
pick_next_rt_entity()) still checks the error condition, which can
never happen, since list_entry() never returns NULL.
Remove the BUG_ON check, and instead emit a warning in the only
possible error condition here: the queue being empty which should
never happen.
Fixes: 326587b84078 ("sched: fix goto retry in pick_next_task_rt()")
Signed-off-by: Pietro Borrello <borrello@diag.uniroma1.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20230128-list-entry-null-check-sched-v3-1-b1a71bd1ac6b@diag.uniroma1.it
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/rt.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index ed2a47e4ddae..0a11f44adee5 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1777,6 +1777,8 @@ static struct sched_rt_entity *pick_next_rt_entity(struct rt_rq *rt_rq) BUG_ON(idx >= MAX_RT_PRIO); queue = array->queue + idx; + if (SCHED_WARN_ON(list_empty(queue))) + return NULL; next = list_entry(queue->next, struct sched_rt_entity, run_list); return next; @@ -1789,7 +1791,8 @@ static struct task_struct *_pick_next_task_rt(struct rq *rq) do { rt_se = pick_next_rt_entity(rt_rq); - BUG_ON(!rt_se); + if (unlikely(!rt_se)) + return NULL; rt_rq = group_rt_rq(rt_se); } while (rt_rq); |