cpuset: fix possible races in cpu/memory hotplug (0b4217b3) · Commits · 戴 / test

Change to cpuset->cpus_allowed and cpuset->mems_allowed should be protected by callback_mutex, otherwise the reader may read wrong cpus/mems. This is cpuset's lock rule. Signed-off-by:

Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

kernel/cpuset.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -2070,7 +2070,9 @@ static int cpuset_track_online_cpus(struct notifier_block *unused_nb,
		}

		cgroup_lock();
		mutex_lock(&callback_mutex);
		cpumask_copy(top_cpuset.cpus_allowed, cpu_online_mask);
		mutex_unlock(&callback_mutex);
		scan_for_empty_cpusets(&top_cpuset);
		ndoms = generate_sched_domains(&doms, &attr);
		cgroup_unlock();
		@@ -2093,10 +2095,11 @@ static int cpuset_track_online_nodes(struct notifier_block *self,
		cgroup_lock();
		switch (action) {
		case MEM_ONLINE:
		top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
		break;
		case MEM_OFFLINE:
		mutex_lock(&callback_mutex);
		top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
		mutex_unlock(&callback_mutex);
		if (action == MEM_OFFLINE)
		scan_for_empty_cpusets(&top_cpuset);
		break;
		default:

Admin message