kernel: mm: hugetlb: fix UAF in hugetlb_handle_userfault

In the Linux kernel, the following vulnerability has been resolved: mm: hugetlb: fix UAF in hugetlbhandleuserfault The vmalock and hugetlbfaultmutex are dropped before handling userfault and reacquire them again after handleuserfault, but reacquire the vmalock could lead to UAF1,2 due to the...