The following commit has been merged into the sched/core branch of tip: Commit-ID: 885b3ba47aa5cc16550beb8a42181ad5e8302ceb Gitweb: https://git.kernel.org/tip/885b3ba47aa5cc16550beb8a42181ad5e8302ceb Author: Valentin Schneider <valentin.schneider@xxxxxxx> AuthorDate: Tue, 13 Oct 2020 15:01:15 +01:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Tue, 10 Nov 2020 18:39:02 +01:00 sched: Deny self-issued __set_cpus_allowed_ptr() when migrate_disable() migrate_disable(); set_cpus_allowed_ptr(current, {something excluding task_cpu(current)}); affine_move_task(); <-- never returns Signed-off-by: Valentin Schneider <valentin.schneider@xxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Link: https://lkml.kernel.org/r/20201013140116.26651-1-valentin.schneider@xxxxxxx --- kernel/sched/core.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index e92d785..88c6fcb 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2238,8 +2238,17 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, 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
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