| Date | Fri, 23 Oct 2020 12:12:16 +0200 | From | Peter Zijlstra <> | Subject | [PATCH v4 18/19] sched: Deny self-issued __set_cpus_allowed_ptr() when migrate_disable() |
| |
From: Valentin Schneider <valentin.schneider@arm.com>
migrate_disable(); set_cpus_allowed_ptr(current, {something excluding task_cpu(current)}); affine_move_task(); <-- never returns
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20201013140116.26651-1-valentin.schneider@arm.com --- kernel/sched/core.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
--- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2182,8 +2182,17 @@ static int __set_cpus_allowed_ptr(struct goto out; } - if (!(flags & SCA_MIGRATE_ENABLE) && cpumask_equal(&p->cpus_mask, new_mask)) - goto out; + if (!(flags & SCA_MIGRATE_ENABLE)) { + if (cpumask_equal(&p->cpus_mask, new_mask)) + goto out; + + if (WARN_ON_ONCE(p == current && + is_migration_disabled(p) && + !cpumask_test_cpu(task_cpu(p), new_mask))) { + ret = -EBUSY; + goto out; + } + } /* * Picking a ~random cpu helps in cases where we are changing affinity
|