In preparation for replaying user affinity requests using a saved mask,
split sched_setaffinity() up so that the initial task lookup and
security checks are only performed when the request is coming directly
from userspace.
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
---
kernel/sched/core.c | 110 +++++++++++++++++++++++---------------------
1 file changed, 58 insertions(+), 52 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 9512623d5a60..808bbe669a6d 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6788,9 +6788,61 @@ SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
return retval;
}
-long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
+static int
+__sched_setaffinity(struct task_struct *p, const struct cpumask *mask)
{
+ int retval;
cpumask_var_t cpus_allowed, new_mask;
+
+ if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL))
+ return -ENOMEM;
+
+ if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
+ return -ENOMEM;
+
+ cpuset_cpus_allowed(p, cpus_allowed);
+ cpumask_and(new_mask, mask, cpus_allowed);
+
+ /*
+ * Since bandwidth control happens on root_domain basis,
+ * if admission test is enabled, we only admit -deadline
+ * tasks allowed to run on all the CPUs in the task's
+ * root_domain.
+ */
+#ifdef CONFIG_SMP
+ if (task_has_dl_policy(p) && dl_bandwidth_enabled()) {
+ rcu_read_lock();
+ if (!cpumask_subset(task_rq(p)->rd->span, new_mask)) {
+ retval = -EBUSY;
+ rcu_read_unlock();
+ goto out_free_masks;
+ }
+ rcu_read_unlock();
+ }
+#endif
+again:
+ retval = __set_cpus_allowed_ptr(p, new_mask, SCA_CHECK);
+ if (retval)
+ goto out_free_masks;
+
+ cpuset_cpus_allowed(p, cpus_allowed);
+ if (!cpumask_subset(new_mask, cpus_allowed)) {
+ /*
+ * We must have raced with a concurrent cpuset update.
+ * Just reset the cpumask to the cpuset's cpus_allowed.
+ */
+ cpumask_copy(new_mask, cpus_allowed);
+ goto again;
+ }
+
+out_free_masks:
+ free_cpumask_var(new_mask);
+ free_cpumask_var(cpus_allowed);
+ return retval;
+}
+
+long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
+{
struct task_struct *p;
int retval;
@@ -6810,68 +6862,22 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
retval = -EINVAL;
goto out_put_task;
}
- if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
- retval = -ENOMEM;
- goto out_put_task;
- }
- if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
- retval = -ENOMEM;
- goto out_free_cpus_allowed;
- }
- retval = -EPERM;
+
if (!check_same_owner(p)) {
rcu_read_lock();
if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
rcu_read_unlock();
- goto out_free_new_mask;
+ retval = -EPERM;
+ goto out_put_task;
}
rcu_read_unlock();
}
retval = security_task_setscheduler(p);
if (retval)
- goto out_free_new_mask;
-
-
- cpuset_cpus_allowed(p, cpus_allowed);
- cpumask_and(new_mask, in_mask, cpus_allowed);
-
- /*
- * Since bandwidth control happens on root_domain basis,
- * if admission test is enabled, we only admit -deadline
- * tasks allowed to run on all the CPUs in the task's
- * root_domain.
- */
-#ifdef CONFIG_SMP
- if (task_has_dl_policy(p) && dl_bandwidth_enabled()) {
- rcu_read_lock();
- if (!cpumask_subset(task_rq(p)->rd->span, new_mask)) {
- retval = -EBUSY;
- rcu_read_unlock();
- goto out_free_new_mask;
- }
- rcu_read_unlock();
- }
-#endif
-again:
- retval = __set_cpus_allowed_ptr(p, new_mask, SCA_CHECK);
+ goto out_put_task;
- if (!retval) {
- cpuset_cpus_allowed(p, cpus_allowed);
- if (!cpumask_subset(new_mask, cpus_allowed)) {
- /*
- * We must have raced with a concurrent cpuset
- * update. Just reset the cpus_allowed to the
- * cpuset's cpus_allowed
- */
- cpumask_copy(new_mask, cpus_allowed);
- goto again;
- }
- }
-out_free_new_mask:
- free_cpumask_var(new_mask);
-out_free_cpus_allowed:
- free_cpumask_var(cpus_allowed);
+ retval = __sched_setaffinity(p, in_mask);
out_put_task:
put_task_struct(p);
return retval;
--
2.31.1.751.gd2f1c929bd-goog
