Messages in this thread Patch in this message | | | Date | Tue, 03 Feb 2009 17:26:15 +0800 | From | Li Zefan <> | Subject | [PATCH] cpuset: fix possible races in cpu/memory hotplug |
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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> --- kernel/cpuset.c | 9 ++++++--- 1 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/kernel/cpuset.c b/kernel/cpuset.c index a856788..39f7d94 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -2061,7 +2061,9 @@ 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(); @@ -2084,11 +2086,12 @@ 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]; - scan_for_empty_cpusets(&top_cpuset); + mutex_unlock(&callback_mutex); + if (action == MEM_OFFLINE) + scan_for_empty_cpusets(&top_cpuset); break; default: break; -- 1.5.4.rc3
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