cgroup: fix spurious lockdep warning in cgroup_exit()

cgroup_exit() is called in fork and exit path. If it's called in the
failure path during fork, PF_EXITING isn't set, and then lockdep will
complain.

Fix this by removing cgroup_exit() in that failure path. cgroup_fork()
does nothing that needs cleanup.

Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 2 insertions, 3 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index a17621c6cd42..8852b3463ab7 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1271,7 +1271,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
         if (IS_ERR(p->mempolicy)) {
                 retval = PTR_ERR(p->mempolicy);
                 p->mempolicy = NULL;
-                goto bad_fork_cleanup_cgroup;
+                goto bad_fork_cleanup_threadgroup_lock;
         }
         mpol_fix_fork_child_flag(p);
 #endif
@@ -1524,11 +1524,10 @@ bad_fork_cleanup_policy:
         perf_event_free_task(p);
 #ifdef CONFIG_NUMA
         mpol_put(p->mempolicy);
-bad_fork_cleanup_cgroup:
+bad_fork_cleanup_threadgroup_lock:
 #endif
         if (clone_flags & CLONE_THREAD)
                 threadgroup_change_end(current);
-        cgroup_exit(p, 0);
         delayacct_tsk_free(p);
         module_put(task_thread_info(p)->exec_domain->module);
 bad_fork_cleanup_count: