Reject explicit requests to change the affinity mask of a task via set_cpus_allowed_ptr() if the requested mask is not a subset of the mask returned by task_cpu_possible_mask(). This ensures that the 'cpus_mask' for a given task cannot contain CPUs which are incapable of executing it, except in cases where the affinity is forced.
Reviewed-by: Quentin Perret <[email protected]> Signed-off-by: Will Deacon <[email protected]> --- kernel/sched/core.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 58474569a2ea..92ac3e53f50a 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1875,6 +1875,7 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask, bool check) { const struct cpumask *cpu_valid_mask = cpu_active_mask; + const struct cpumask *cpu_allowed_mask = task_cpu_possible_mask(p); unsigned int dest_cpu; struct rq_flags rf; struct rq *rq; @@ -1888,6 +1889,9 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, * Kernel threads are allowed on online && !active CPUs */ cpu_valid_mask = cpu_online_mask; + } else if (!cpumask_subset(new_mask, cpu_allowed_mask)) { + ret = -EINVAL; + goto out; } /* -- 2.29.2.576.ga3fc446d84-goog
