futex: Use correct exit on failure from futex_hash_allocate_default()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: futex: Use correct exit on failure from futex_hash_allocate_default() copy_process() uses the wrong error exit path from futex_hash_allocate_default(). After exiting from futex_hash_allocate_default(), neither tasklist_lock nor siglock has been acquired. The exit label bad_fork_core_free unlocks both of these locks which is wrong. The next exit label, bad_fork_cancel_cgroup, is the correct exit. sched_cgroup_fork() did not allocate any resources that need to freed. Use bad_fork_cancel_cgroup on error exit from futex_hash_allocate_default().

References

• https://git.kernel.org/stable/c/f1635765cd0fdbf27b04d9a50be91a01b5adda13
• https://git.kernel.org/stable/c/4ec3c15462b9f44562f45723a92e2807746ba7d1