Files
linux/kernel
Tejun Heo e446300968 cgroup: Fix threadgroup_rwsem <-> cpus_read_lock() deadlock
commit 4f7e723643 upstream.

Add #include <linux/cpu.h> to avoid compile error on some architectures.

commit 9a3284fad4 ("cgroup: Optimize single thread migration") and
commit 671c11f061 ("cgroup: Elide write-locking threadgroup_rwsem
when updating csses on an empty subtree") are not backport. So ignore the
input parameter of cgroup_attach_lock/cgroup_attach_unlock.

original commit message:

Bringing up a CPU may involve creating and destroying tasks which requires
read-locking threadgroup_rwsem, so threadgroup_rwsem nests inside
cpus_read_lock(). However, cpuset's ->attach(), which may be called with
thredagroup_rwsem write-locked, also wants to disable CPU hotplug and
acquires cpus_read_lock(), leading to a deadlock.

Fix it by guaranteeing that ->attach() is always called with CPU hotplug
disabled and removing cpus_read_lock() call from cpuset_attach().

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-and-tested-by: Imran Khan <imran.f.khan@oracle.com>
Reported-and-tested-by: Xuewen Yan <xuewen.yan@unisoc.com>
Fixes: 05c7b7a92c ("cgroup/cpuset: Fix a race between cpuset_attach() and cpu hotplug")
Cc: stable@vger.kernel.org # v5.17+
Signed-off-by: Cai Xinchen <caixinchen1@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-05 11:15:43 +02:00
..
2023-01-18 11:30:39 +01:00
2019-12-13 08:51:11 +01:00
2019-12-01 09:17:17 +01:00
2021-02-10 09:21:06 +01:00
2023-02-06 07:49:41 +01:00
2020-03-25 08:06:13 +01:00
2019-01-13 09:51:06 +01:00
2021-02-07 14:48:38 +01:00
2020-01-09 10:18:59 +01:00