Task hangs in blk_mq_get_tag() while no tags are in use

Issue

• Task hangs in blk_mq_get_tag() while no tags are in use:

INFO: task fio:52039 blocked for more than 120 seconds.
      Tainted: G           OE    --------- -  - 4.18.0-372.9.1.el8.x86_64 #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:fio             state:D stack:    0 pid:52039 ppid: 51845 flags:0x00004080
Call Trace:
 __schedule+0x2d1/0x830
 schedule+0x35/0xa0
 io_schedule+0x12/0x40
 blk_mq_get_tag+0x121/0x280
 ? finish_wait+0x80/0x80
 __blk_mq_alloc_request+0x47/0x110
 blk_mq_make_request+0x14f/0x5b0
 generic_make_request+0xef/0x350
 ? blkg_lookup_slowpath+0x25/0x50
 submit_bio+0x3c/0x160
 ? set_page_dirty_lock+0x38/0x50
 ? bio_set_pages_dirty+0x32/0x50
 do_blockdev_direct_IO+0x21e5/0x2e60
 ? __switch_to_asm+0x35/0x70
....
 ? ext4_dio_get_block_unwritten_sync+0x50/0x50 [ext4]
 ext4_direct_IO+0x171/0x800 [ext4]
 ? touch_atime+0x33/0xe0
 generic_file_read_iter+0x8f/0x150
 aio_read+0xd5/0x180
 ? io_submit_one+0x7e/0x3c0
 ? kmem_cache_alloc+0x13f/0x280
 io_submit_one+0x20b/0x3c0
 __x64_sys_io_submit+0xa2/0x180
 ? syscall_trace_enter+0x1fb/0x2c0
 do_syscall_64+0x5b/0x1a0
 entry_SYSCALL_64_after_hwframe+0x65/0xca