nsproxy: fix free_nsproxy() and simplify create_new_namespaces()

Make it possible to handle NULL being passed to the reference count
helpers instead of forcing the caller to handle this. Afterwards we can
nicely allow a cleanup guard to handle nsproxy freeing.

Active reference count handling is not done in nsproxy_free() but rather
in free_nsproxy() as nsproxy_free() is also called from setns() failure
paths where a new nsproxy has been prepared but has not been marked as
active via switch_task_namespaces().

Link: https://lore.kernel.org/690bfb9e.050a0220.2e3c35.0013.GAE@google.com
Link: https://patch.msgid.link/20251111-sakralbau-guthaben-7dcc277d337f@brauner
Fixes: 3c9820d5c64a ("ns: add active reference count")
Reported-by: syzbot+0b2e79f91ff6579bfa5b@syzkaller.appspotmail.com
Reported-by: syzbot+0a8655a80e189278487e@syzkaller.appspotmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

0 files changed, 0 insertions, 0 deletions