diff options
| author | Pietro Borrello <borrello@diag.uniroma1.it> | 2023-02-06 22:33:54 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-08-30 16:31:56 +0200 |
| commit | 84d90fb72a053c034b018fcc3cfaa6f606faf1c6 (patch) | |
| tree | 92f22b102de6176fd6d463dd582799cdb235953e /kernel | |
| parent | b3cd44bff89566bca59fa9cdeb1cd29c8c57752e (diff) | |
sched/rt: pick_next_rt_entity(): check list_entry
commit 7c4a5b89a0b5a57a64b601775b296abf77a9fe97 upstream.
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Fixes CVE-2023-1077: sched/rt: pick_next_rt_entity(): check list_entry
An insufficient list empty checking in pick_next_rt_entity(). The
_pick_next_task_rt() checks pick_next_rt_entity() returns NULL or not
but pick_next_rt_entity() never returns NULL. So, even if the list is
empty, _pick_next_task_rt() continues its process. ]
Signed-off-by: Srish Srinivasan <ssrish@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -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 9c6c3572b131..394c66442cff 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1522,6 +1522,8 @@ static struct sched_rt_entity *pick_next_rt_entity(struct rq *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; @@ -1535,7 +1537,8 @@ static struct task_struct *_pick_next_task_rt(struct rq *rq) do { rt_se = pick_next_rt_entity(rq, rt_rq); - BUG_ON(!rt_se); + if (unlikely(!rt_se)) + return NULL; rt_rq = group_rt_rq(rt_se); } while (rt_rq); |