Given the following code containing errors, provide Common Weakness Enumeration (CWE) identifiers and corresponding messages in JSON format. Each identified weakness should have a unique entry in the JSON array.
    Code: static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
			 struct ctl_table *table, int write,
			 void *buffer, size_t *length, loff_t *ppos)
{
	struct hstate *h = &default_hstate;
	unsigned long tmp = h->max_huge_pages;
	int ret;

	if (!hugepages_supported())
		return -EOPNOTSUPP;

	table->data = &tmp;
	table->maxlen = sizeof(unsigned long);
	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
	if (ret)
		goto out;

	if (write)
		ret = __nr_hugepages_store_common(obey_mempolicy, h,
						  NUMA_NO_NODE, tmp, *length);
out:
	return ret;
} ; Sample JSON Format Confermily Expected output: "examples" => "cwe": "xxx"; "message": "xxx"
    
 'cwe': ['CWE-362'], 'message': 'mm/hugetlb: fix a race between hugetlb sysctl handlers

There is a race between the assignment of `table->data` and write value
to the pointer of `table->data` in the __do_proc_doulongvec_minmax() on
the other thread.

  CPU0:                                 CPU1:
                                        proc_sys_write
  hugetlb_sysctl_handler                  proc_sys_call_handler
  hugetlb_sysctl_handler_common             hugetlb_sysctl_handler
    table->data = &tmp;                       hugetlb_sysctl_handler_common
                                                table->data = &tmp;
      proc_doulongvec_minmax
        do_proc_doulongvec_minmax           sysctl_head_finish
          __do_proc_doulongvec_minmax         unuse_table
            i = table->data;
            *i = val;  // corrupt CPU1's stack

Fix this by duplicating the `table`, and only update the duplicate of
it.  And introduce a helper of proc_hugetlb_doulongvec_minmax() to
simplify the code.

The following oops was seen:

    BUG: kernel NULL pointer dereference, address: 0000000000000000
    #PF: supervisor instruction fetch in kernel mode
    #PF: error_code(0x0010) - not-present page
    Code: Bad RIP value.
    ...
    Call Trace:
     ? set_max_huge_pages+0x3da/0x4f0
     ? alloc_pool_huge_page+0x150/0x150
     ? proc_doulongvec_minmax+0x46/0x60
     ? hugetlb_sysctl_handler_common+0x1c7/0x200
     ? nr_hugepages_store+0x20/0x20
     ? copy_fd_bitmaps+0x170/0x170
     ? hugetlb_sysctl_handler+0x1e/0x20
     ? proc_sys_call_handler+0x2f1/0x300
     ? unregister_sysctl_table+0xb0/0xb0
     ? __fd_install+0x78/0x100
     ? proc_sys_write+0x14/0x20
     ? __vfs_write+0x4d/0x90
     ? vfs_write+0xef/0x240
     ? ksys_write+0xc0/0x160
     ? __ia32_sys_read+0x50/0x50
     ? __close_fd+0x129/0x150
     ? __x64_sys_write+0x43/0x50
     ? do_syscall_64+0x6c/0x200
     ? entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: e5ff215941d5 ("hugetlb: multiple hstates for multiple page sizes")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20200828031146.43035-1-songmuchun@bytedance.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>'