sched_ext: Reject setting disallow from init_task outside the enable path

Browse source

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: 337ec00b1d ("sched_ext: Implement cgroup sub-sched enabling and disabling")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

...

This commit is contained in:

Tejun Heo 2026-07-16 10:43:25 -10:00

parent 0e2f4ab68a

commit 477869bfaf

2 changed files with 8 additions and 5 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

10

include/linux/sched/ext.h

View file

3

kernel/sched/ext/ext.c

View file