System hang due to soft lockup during snapshot removal with large hash list traversal in dm_exception_table_exit()

Issue

• System hang due to soft lockup during snapshot removal with large hash list traversal in dm_exception_table_exit():

[52201162.937275] NMI watchdog: BUG: soft lockup - CPU#69 stuck for 22s! [migration/69:357]
[52201162.937819] Kernel panic - not syncing: softlockup: hung tasks
....
PID: 76427    TASK: ffff9ae8f03f6300  CPU: 84   COMMAND: "lvremove"
 #0 [ffff9ac83ef48e48] crash_nmi_callback at ffffffffb7658567
 #1 [ffff9ac83ef48e58] nmi_handle at ffffffffb7d8d93c
 #2 [ffff9ac83ef48eb0] do_nmi at ffffffffb7d8db5d
 #3 [ffff9ac83ef48ef0] end_repeat_nmi at ffffffffb7d8cd9c
    [exception RIP: __slab_free+136]
    RIP: ffffffffb78260a8  RSP: ffff9aec42c27b10  RFLAGS: 00000286
    RAX: 0000000000000000  RBX: ffff9ac9f6e233c0  RCX: 000000010080001e
    RDX: ffff9ac9f6e23a60  RSI: ffffea9006db88c0  RDI: 0000000040000000
    RBP: ffff9aec42c27bb0   R8: 0000000000000001   R9: 000000010080001d
    R10: ffff9ac83ef5f080  R11: ffff9ac9f6e23a60  R12: 000000000080001d
    R13: ffff9aa9bfc07c00  R14: ffffea9006db88c0  R15: 0000000000000000
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
--- <NMI exception stack> ---
 #4 [ffff9aec42c27b10] __slab_free at ffffffffb78260a8
 #5 [ffff9aec42c27bb8] kmem_cache_free at ffffffffb78268f2
 #6 [ffff9aec42c27be0] dm_exception_table_exit at ffffffffc077a40e [dm_snapshot]
 #7 [ffff9aec42c27c18] snapshot_dtr at ffffffffc077a5dc [dm_snapshot]
 #8 [ffff9aec42c27c50] dm_table_destroy at ffffffffc03098d3 [dm_mod]
 #9 [ffff9aec42c27c90] dev_suspend at ffffffffc030ded6 [dm_mod]
#10 [ffff9aec42c27cc0] ctl_ioctl at ffffffffc030f04b [dm_mod]
#11 [ffff9aec42c27e70] dm_ctl_ioctl at ffffffffc030f44e [dm_mod]
#12 [ffff9aec42c27e80] do_vfs_ioctl at ffffffffb7863590
#13 [ffff9aec42c27f00] sys_ioctl at ffffffffb7863841
#14 [ffff9aec42c27f50] system_call_fastpath at ffffffffb7d95f92