drop_caches operation never completes due to an infinite loop in drop_slab_node()

Issue

• drop_caches operation (echo 2 > /proc/sys/vm/drop_caches) hangs and never completes.
• According to the perf report analysis, it clearly seems like an infinite loop in drop_slab_node():

Samples: 795K of event 'cycles', Event count (approx.): 628039662176
  Overhead  Command  Shared Object
-   99.83%  bash     [kernel.vmlinux]                              ▒
   - 78.48% mem_cgroup_iter                                        ▒
        drop_slab_node                                             ▒
        drop_slab                                                  ▒
        drop_caches_sysctl_handler                                 ▒
        proc_sys_call_handler                                      ▒
        vfs_write                                                  ▒
        ksys_write                                                 ▒
        do_syscall_64                                              ▒
        entry_SYSCALL_64_after_hwframe                             ▒
        0x7ffff76f8bc8                                             ▒
        0                                                          ▒
   - 13.14% css_next_descendant_pre                                ▒
        mem_cgroup_iter                                            ▒
        drop_slab_node                                             ▒
        drop_slab                                                  ▒
        drop_caches_sysctl_handler                                 ▒
        proc_sys_call_handler                                      ▒
        vfs_write                                                  ▒
        ksys_write                                                 ▒
        do_syscall_64                                              ▒
        entry_SYSCALL_64_after_hwframe                             ▒
        0x7ffff76f8bc8                                             ▒
        0                                                          ◆
   - 3.69% percpu_ref_put_many.constprop.80                        ▒
      - 3.69% mem_cgroup_iter                                      ▒
           drop_slab_node                                          ▒
           drop_slab                                               ▒
           drop_caches_sysctl_handler                              ▒
           proc_sys_call_handler                                   ▒
           vfs_write                                               ▒
           ksys_write                                              ▒
           do_syscall_64                                           ▒
           entry_SYSCALL_64_after_hwframe                          ▒
           0x7ffff76f8bc8                                          ▒
           0                                                       ▒
   + 1.25% shrink_slab                                             ▒
   + 0.68% drop_slab_node                                          ▒
        ...