System hangs due to deadlock during allocation through loop device

Issue

• System hang due to deadlock during allocation through loop device

PID: 3049   TASK: ffff880809b52280  CPU: 3   COMMAND: "loop1"
 #0 [ffff88080a09b2d0] __schedule at ffffffff8163a32d
 #1 [ffff88080a09b338] schedule_preempt_disabled at ffffffff8163baa9
 #2 [ffff88080a09b348] __mutex_lock_slowpath at ffffffff816397a5
 #3 [ffff88080a09b3b8] shrink at ffffffffa04d4b88 [dm_bufio]
 #4 [ffff88080a09b420] shrink_slab at ffffffff8117c46b
 #5 [ffff88080a09b4c0] do_try_to_free_pages at ffffffff8117f6a2
 #6 [ffff88080a09b538] try_to_free_pages at ffffffff8117f8bc
 #7 [ffff88080a09b5d0] __alloc_pages_nodemask at ffffffff811735bd
 #8 [ffff88080a09b708] alloc_pages_current at ffffffff811b4429
 #9 [ffff88080a09b750] new_slab at ffffffff811be975
#10 [ffff88080a09b788] __slab_alloc at ffffffff8163220f
#11 [ffff88080a09b868] __radix_tree_preload at ffffffff812f7e05
#12 [ffff88080a09b8a0] __radix_tree_preload at ffffffff812f7e05
#13 [ffff88080a09b8c8] radix_tree_maybe_preload at ffffffff812f7ec9
#14 [ffff88080a09b8d8] __add_to_page_cache_locked at ffffffff8116959b
#15 [ffff88080a09b930] add_to_page_cache_lru at ffffffff811697c7
#16 [ffff88080a09b960] grab_cache_page_write_begin at ffffffff81169c1f
#17 [ffff88080a09b9a0] ext4_da_write_begin at ffffffffa01d9617 [ext4]
#18 [ffff88080a09ba20] generic_file_buffered_write at ffffffff81169ded
#19 [ffff88080a09bae8] __generic_file_aio_write at ffffffff8116b315
#20 [ffff88080a09bb60] generic_file_aio_write at ffffffff8116b57d
#21 [ffff88080a09bba0] ext4_file_write at ffffffffa01ceb65 [ext4]
#22 [ffff88080a09bc58] do_sync_write at ffffffff811ddd7d
#23 [ffff88080a09bd30] __do_lo_send_write at ffffffffa04c280f [loop]
#24 [ffff88080a09bd78] do_lo_send_direct_write at ffffffffa04c2922 [loop]
#25 [ffff88080a09bdb0] do_bio_filebacked at ffffffffa04c2c57 [loop]
#26 [ffff88080a09be58] loop_thread at ffffffffa04c348c [loop]
#27 [ffff88080a09bec8] kthread at ffffffff810a5acf
#28 [ffff88080a09bf50] ret_from_fork at ffffffff81645998

PID: 129724  TASK: ffff88045fb68000  CPU: 0   COMMAND: "kworker/u256:5"
 #0 [ffff88000b5979f0] __schedule at ffffffff8163a32d
 #1 [ffff88000b597a58] schedule at ffffffff8163a9c9
 #2 [ffff88000b597a68] schedule_timeout at ffffffff816386b9
 #3 [ffff88000b597b18] io_schedule_timeout at ffffffff81639ffe
 #4 [ffff88000b597b48] io_schedule at ffffffff8163a098
 #5 [ffff88000b597b58] do_io_schedule at ffffffffa04d30ee [dm_bufio]
 #6 [ffff88000b597b68] __wait_on_bit at ffffffff81638840
 #7 [ffff88000b597ba8] out_of_line_wait_on_bit at ffffffff816388f7
 #8 [ffff88000b597c20] dm_bufio_write_dirty_buffers at ffffffffa04d50f1 [dm_bufio]
 #9 [ffff88000b597c80] dm_bm_flush at ffffffffa04e631c [dm_persistent_data]
#10 [ffff88000b597c90] dm_tm_pre_commit at ffffffffa04e9d8f [dm_persistent_data]
#11 [ffff88000b597ca8] __commit_transaction at ffffffffa05046a7 [dm_thin_pool]
#12 [ffff88000b597d20] dm_pool_commit_metadata at ffffffffa0505e77 [dm_thin_pool]
#13 [ffff88000b597d48] commit at ffffffffa04fed26 [dm_thin_pool]
#14 [ffff88000b597d78] do_worker at ffffffffa05031b2 [dm_thin_pool]
#15 [ffff88000b597e20] process_one_work at ffffffff8109d5db
#16 [ffff88000b597e68] worker_thread at ffffffff8109e3ab
#17 [ffff88000b597ec8] kthread at ffffffff810a5acf
#18 [ffff88000b597f50] ret_from_fork at ffffffff81645998