diff options
| author | Tejun Heo <tj@kernel.org> | 2026-07-16 10:43:25 -1000 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2026-07-17 21:28:57 -1000 |
| commit | 477869bfafea65492d23de62c1b5208147c09dd2 (patch) | |
| tree | 79b9b675d79761cb0059c2efd45c0d6a5cfb2287 /kernel | |
| parent | 0e2f4ab68a89fad42e0f5a9ff4b740738e7aa1d6 (diff) | |
sched_ext: Reject setting disallow from init_task outside the enable path
The p->scx.disallow revert assumes the root enable path, where the switching
loop reads the reverted policy right afterwards and leaves the task off SCX.
The sub-scheduler disable path also reaches it when re-initializing the
returned tasks on a root parent. Nothing reads the policy there: the task is
enabled on root anyway and keeps running on the ext class with a silently
rewritten policy.
Kill the sched instead, matching the fork and non-root branches, and update
the disallow documentation, which equated !fork with the load path and
pointed at a stale debugfs path for nr_rejected.
Fixes: 337ec00b1d9c ("sched_ext: Implement cgroup sub-sched enabling and disabling")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/ext/ext.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c index e3fa7b2fac9d..46f135bddd46 100644 --- a/kernel/sched/ext/ext.c +++ b/kernel/sched/ext/ext.c @@ -3606,6 +3606,9 @@ static int __scx_init_task(struct scx_sched *sch, struct task_struct *p, bool fo } else if (unlikely(fork)) { scx_error(sch, "ops.init_task() set task->scx.disallow for %s[%d] during fork", p->comm, p->pid); + } else if (unlikely(scx_enable_state() != SCX_ENABLING)) { + scx_error(sch, "ops.init_task() set task->scx.disallow for %s[%d] outside the enable path", + p->comm, p->pid); } else { struct rq *rq; struct rq_flags rf; |