mirror of
https://github.com/hardkernel/linux.git
synced 2026-03-24 19:40:21 +09:00
46307fd6e2
The commit74e4b956ebincorrectly wrapped kernfs_walk_and_get (might_sleep) under css_set_lock (spinlock). css_set_lock is needed by __cset_cgroup_from_root to ensure stable cset->cgrp_links but not for kernfs_walk_and_get. We only need to make sure that the returned root_cgrp won't be freed under us. This is given in the case of global root because it is static (cgrp_dfl_root.cgrp). When the root_cgrp is lower in the hierarchy, it is pinned by cgroup_ns->root_cset (and `current` task cannot switch namespace asynchronously so ns_proxy pins cgroup_ns). Note this reasoning won't hold for root cgroups in v1 hierarchies, therefore create a special-cased helper function just for the default hierarchy. Fixes:74e4b956eb("cgroup: Honor caller's cgroup NS when resolving path") Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>