On Mon, Aug 15, 2022 at 01:27:38PM -1000, Tejun Heo wrote: > Bringing up a CPU may involve creating new 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@xxxxxxxxxx> Applied to cgroup/for-6.0-fixes w/ commit message and comment update suggested by Xuewen and Fixes / stable tags added. Thanks. -- tejun
