Hello I found the scsi-debug module removing [1] takes more than 3mins during blktests srp/ tests, and bisecting shows it was introduced from [2], Pls help check it, let me know if you need more info for it, thanks. [1] # time ./check srp/001 srp/001 (Create and remove LUNs) [passed] runtime ... 3.194s real 3m12.119s user 0m0.859s sys 0m2.227s # ps aux | grep modprobe root 250153 0.0 0.0 10600 2264 pts/0 D+ 01:34 0:00 modprobe -r scsi_debug # cat /proc/250153/stack [<0>] blk_execute_rq+0x95/0xb0 [<0>] __scsi_execute+0xe2/0x250 [<0>] sd_sync_cache+0xac/0x190 [<0>] sd_shutdown+0x67/0xf0 [<0>] sd_remove+0x39/0x80 [<0>] __device_release_driver+0x234/0x240 [<0>] device_release_driver+0x23/0x30 [<0>] bus_remove_device+0xd8/0x140 [<0>] device_del+0x18b/0x3f0 [<0>] __scsi_remove_device+0x102/0x140 [<0>] scsi_forget_host+0x55/0x60 [<0>] scsi_remove_host+0x72/0x110 [<0>] sdebug_driver_remove+0x22/0xa0 [scsi_debug] [<0>] __device_release_driver+0x181/0x240 [<0>] device_release_driver+0x23/0x30 [<0>] bus_remove_device+0xd8/0x140 [<0>] device_del+0x18b/0x3f0 [<0>] device_unregister+0x13/0x60 [<0>] sdebug_do_remove_host+0xd1/0xf0 [scsi_debug] [<0>] scsi_debug_exit+0x58/0xe1e [scsi_debug] [<0>] __do_sys_delete_module.constprop.0+0x170/0x260 [<0>] do_syscall_64+0x3a/0x80 [<0>] entry_SYSCALL_64_after_hwframe+0x44/0xae # dmesg | tail -10 [ 345.863755] ib_srpt:srpt_release_channel_work: ib_srpt 10.16.221.74-32 [ 345.863855] ib_srpt:srpt_release_channel_work: ib_srpt 10.16.221.74-34 [ 345.863953] ib_srpt:srpt_release_channel_work: ib_srpt 10.16.221.74-36 [ 346.373371] sd 15:0:0:0: [sdb] Synchronizing SCSI cache [ 532.864536] sd 15:0:0:0: [sdb] Synchronize Cache(10) failed: Result: hostbyte=DID_TIME_OUT driverbyte=DRIVER_OK ------> seems most of the time were taken here [ 532.929626] eno1np0 speed is unknown, defaulting to 1000 [ 532.938524] eno2np1 speed is unknown, defaulting to 1000 [ 532.943957] eno4 speed is unknown, defaulting to 1000 [ 532.998059] rdma_rxe: rxe-ah pool destroyed with unfree'd elem [ 533.011781] rdma_rxe: unloaded [2] commit 2aad3cd8537033cd34f70294a23f54623ffe9c1b (refs/bisect/bad) Author: Douglas Gilbert <dgilbert@xxxxxxxxxxxx> Date: Sat Jan 8 20:28:45 2022 -0500 scsi: scsi_debug: Address races following module load