In the Linux kernel, the following vulnerability has been resolved:
scsi: target: core: Add TMF to tmr_list handling
An abort that is responded to by iSCSI itself is added to tmr_list but does not go to target core. A LUN_RESET that goes through tmr_list takes a refcounter on the abort and waits for completion. However, the abort will be never complete because it was not started in target core.
Unable to locate ITT: 0x05000000 on CID: 0 Unable to locate RefTaskTag: 0x05000000 on CID: 0. wait_for_tasks: Stopping tmf LUN_RESET with tag 0x0 ref_task_tag 0x0 i_state 34 t_state ISTATE_PROCESSING refcnt 2 transport_state active,stop,fabric_stop wait for tasks: tmf LUN_RESET with tag 0x0 ref_task_tag 0x0 i_state 34 t_state ISTATE_PROCESSING refcnt 2 transport_state active,stop,fabric_stop … INFO: task kworker/0:2:49 blocked for more than 491 seconds. task:kworker/0:2 state:D stack: 0 pid: 49 ppid: 2 flags:0x00000800 Workqueue: events target_tmr_work [target_core_mod] Call Trace: __switch_to+0x2c4/0x470 _schedule+0x314/0x1730 schedule+0x64/0x130 schedule_timeout+0x168/0x430 wait_for_completion+0x140/0x270 target_put_cmd_and_wait+0x64/0xb0 [target_core_mod] core_tmr_lun_reset+0x30/0xa0 [target_core_mod] target_tmr_work+0xc8/0x1b0 [target_core_mod] process_one_work+0x2d4/0x5d0 worker_thread+0x78/0x6c0
To fix this, only add abort to tmr_list if it will be handled by target core.