linux/kernel/cgroup
Zhang Qiao ffed0bf6a6 cgroup/cpuset: Fix a race between cpuset_attach() and cpu hotplug
commit 05c7b7a92c upstream.

As previously discussed(https://lkml.org/lkml/2022/1/20/51),
cpuset_attach() is affected with similar cpu hotplug race,
as follow scenario:

     cpuset_attach()				cpu hotplug
    ---------------------------            ----------------------
    down_write(cpuset_rwsem)
    guarantee_online_cpus() // (load cpus_attach)
					sched_cpu_deactivate
					  set_cpu_active()
					  // will change cpu_active_mask
    set_cpus_allowed_ptr(cpus_attach)
      __set_cpus_allowed_ptr_locked()
       // (if the intersection of cpus_attach and
         cpu_active_mask is empty, will return -EINVAL)
    up_write(cpuset_rwsem)

To avoid races such as described above, protect cpuset_attach() call
with cpu_hotplug_lock.

Fixes: be367d0992 ("cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time")
Cc: stable@vger.kernel.org # v2.6.32+
Reported-by: Zhao Gongyi <zhaogongyi@huawei.com>
Signed-off-by: Zhang Qiao <zhangqiao22@huawei.com>
Acked-by: Waiman Long <longman@redhat.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-02 11:47:47 +01:00
..
cgroup-internal.h cgroup: Use open-time cgroup namespace for process migration perm checks 2022-01-11 15:35:15 +01:00
cgroup-v1.c cgroup-v1: Require capabilities to set release_agent 2022-02-05 12:38:57 +01:00
cgroup.c psi: Fix uaf issue when psi trigger is destroyed while being polled 2022-02-01 17:27:01 +01:00
cpuset.c cgroup/cpuset: Fix a race between cpuset_attach() and cpu hotplug 2022-03-02 11:47:47 +01:00
debug.c kernel: cgroup: fix misuse of %x 2019-05-06 08:47:48 -07:00
freezer.c cgroup: freezer: don't change task and cgroups status unnecessarily 2019-11-07 07:38:41 -08:00
legacy_freezer.c cgroup: rename freezer.c into legacy_freezer.c 2019-04-19 11:26:48 -07:00
Makefile cgroup: Add misc cgroup controller 2021-04-04 13:34:46 -04:00
misc.c svm/sev: Register SEV and SEV-ES ASIDs to the misc controller 2021-04-04 13:34:46 -04:00
namespace.c memcg: enable accounting for new namesapces and struct nsproxy 2021-09-03 09:58:12 -07:00
pids.c clone3: allow spawning processes into cgroups 2020-02-12 17:57:51 -05:00
rdma.c cgroup: fix spelling mistakes 2021-05-24 12:45:26 -04:00
rstat.c cgroup: Fix rootcg cpu.stat guest double counting 2021-11-18 19:16:45 +01:00