Merge "sched: core: Fix possible hotplug race in set_cpus_allowed_ptr" (6ddbd82c) · Commits · e / devices / android_kernel_oneplus_sm8150

kernel/sched/core.c

+39 −16

Original line number	Diff line number	Diff line
		@@ -1105,10 +1105,18 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
		if (cpumask_equal(&p->cpus_allowed, new_mask))
		goto out;

		cpumask_andnot(&allowed_mask, new_mask, cpu_isolated_mask);
		cpumask_and(&allowed_mask, &allowed_mask, cpu_valid_mask);

		dest_cpu = cpumask_any(&allowed_mask);
		if (dest_cpu >= nr_cpu_ids) {
		cpumask_and(&allowed_mask, cpu_valid_mask, new_mask);
		dest_cpu = cpumask_any(&allowed_mask);
		if (!cpumask_intersects(new_mask, cpu_valid_mask)) {
		ret = -EINVAL;
		goto out;
		}
		}

		do_set_cpus_allowed(p, new_mask);

		@@ -1126,7 +1134,6 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
		if (cpumask_test_cpu(task_cpu(p), &allowed_mask))
		goto out;

		dest_cpu = cpumask_any_and(cpu_valid_mask, new_mask);
		if (task_running(rq, p) \|\| p->state == TASK_WAKING) {
		struct migration_arg arg = { p, dest_cpu };
		/* Need help from migration thread: drop lock and wait. */
		@@ -4753,6 +4760,8 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
		cpumask_var_t cpus_allowed, new_mask;
		struct task_struct *p;
		int retval;
		int dest_cpu;
		cpumask_t allowed_mask;

		rcu_read_lock();

		@@ -4814,8 +4823,10 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
		}
		#endif
		again:
		cpumask_andnot(&allowed_mask, new_mask, cpu_isolated_mask);
		dest_cpu = cpumask_any_and(cpu_active_mask, &allowed_mask);
		if (dest_cpu < nr_cpu_ids) {
		retval = __set_cpus_allowed_ptr(p, new_mask, true);

		if (!retval) {
		cpuset_cpus_allowed(p, cpus_allowed);
		if (!cpumask_subset(new_mask, cpus_allowed)) {
		@@ -4828,6 +4839,10 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
		goto again;
		}
		}
		} else {
		retval = -EINVAL;
		}

		out_free_new_mask:
		free_cpumask_var(new_mask);
		out_free_cpus_allowed:
		@@ -4891,6 +4906,14 @@ long sched_getaffinity(pid_t pid, struct cpumask *mask)

		raw_spin_lock_irqsave(&p->pi_lock, flags);
		cpumask_and(mask, &p->cpus_allowed, cpu_active_mask);

		/* The userspace tasks are forbidden to run on
		* isolated CPUs. So exclude isolated CPUs from
		* the getaffinity.
		*/
		if (!(p->flags & PF_KTHREAD))
		cpumask_andnot(mask, mask, cpu_isolated_mask);

		raw_spin_unlock_irqrestore(&p->pi_lock, flags);

		out_unlock: