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 arch_cpu_allowed_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.
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
---
kernel/sched/core.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 8df38ebfe769..13bdb2ae4d3f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1877,6 +1877,7 @@ static int __set_cpus_allowed_ptr_locked(struct task_struct *p,
struct rq_flags *rf)
{
const struct cpumask *cpu_valid_mask = cpu_active_mask;
+ const struct cpumask *cpu_allowed_mask = arch_cpu_allowed_mask(p);
unsigned int dest_cpu;
int ret = 0;
@@ -1887,6 +1888,9 @@ static int __set_cpus_allowed_ptr_locked(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;
}
/*
--
2.29.2.299.gdc1121823c-goog
