From 12b6fcd0ea7f3cb7c3b34668fc678779924123ae Mon Sep 17 00:00:00 2001 From: Dmitry Bogdanov Date: Mon, 18 Oct 2021 16:57:53 +0300 Subject: scsi: target: core: Remove from tmr_list during LUN unlink Currently TMF commands are removed from de_device.dev_tmf_list at the very end of se_cmd lifecycle. However, se_lun unlinks from se_cmd upon a command status (response) being queued in transport layer. This means that LUN and backend device can be deleted in the meantime and a panic will occur: target_tmr_work() cmd->se_tfo->queue_tm_rsp(cmd); // send abort_rsp to a wire transport_lun_remove_cmd(cmd) // unlink se_cmd from se_lun - // - // - // - <<<--- lun remove <<<--- core backend device remove - // - // - // - qlt_handle_abts_completion() tfo->free_mcmd() transport_generic_free_cmd() target_put_sess_cmd() core_tmr_release_req() { if (dev) { // backend device, can not be null spin_lock_irqsave(&dev->se_tmr_lock, flags); //<<<--- CRASH Call Trace: NIP [c000000000e1683c] _raw_spin_lock_irqsave+0x2c/0xc0 LR [c00800000e433338] core_tmr_release_req+0x40/0xa0 [target_core_mod] Call Trace: (unreliable) 0x0 target_put_sess_cmd+0x2a0/0x370 [target_core_mod] transport_generic_free_cmd+0x6c/0x1b0 [target_core_mod] tcm_qla2xxx_complete_mcmd+0x28/0x50 [tcm_qla2xxx] process_one_work+0x2c4/0x5c0 worker_thread+0x88/0x690 For the iSCSI protocol this is easily reproduced: - Send some SCSI sommand - Send Abort of that command over iSCSI - Remove LUN on target - Send next iSCSI command to acknowledge the Abort_Response - Target panics There is no need to keep the command in tmr_list until response completion, so move the removal from tmr_list from the response completion to the response queueing when the LUN is unlinked. Move the removal from state list too as it is a subject to the same race condition. Link: https://lore.kernel.org/r/20211018135753.15297-1-d.bogdanov@yadro.com Fixes: c66ac9db8d4a ("[SCSI] target: Add LIO target core v4.0.0-rc6") Reviewed-by: Roman Bolshakov Reviewed-by: Mike Christie Signed-off-by: Dmitry Bogdanov Signed-off-by: Martin K. Petersen --- drivers/target/target_core_tmr.c | 17 +---------------- 1 file changed, 1 insertion(+), 16 deletions(-) (limited to 'drivers/target/target_core_tmr.c') diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c index e7fcbc09f9db..bac111456fa1 100644 --- a/drivers/target/target_core_tmr.c +++ b/drivers/target/target_core_tmr.c @@ -50,15 +50,6 @@ EXPORT_SYMBOL(core_tmr_alloc_req); void core_tmr_release_req(struct se_tmr_req *tmr) { - struct se_device *dev = tmr->tmr_dev; - unsigned long flags; - - if (dev) { - spin_lock_irqsave(&dev->se_tmr_lock, flags); - list_del_init(&tmr->tmr_list); - spin_unlock_irqrestore(&dev->se_tmr_lock, flags); - } - kfree(tmr); } @@ -156,13 +147,6 @@ void core_tmr_abort_task( se_cmd->state_active = false; spin_unlock_irqrestore(&dev->queues[i].lock, flags); - /* - * Ensure that this ABORT request is visible to the LU - * RESET code. - */ - if (!tmr->tmr_dev) - WARN_ON_ONCE(transport_lookup_tmr_lun(tmr->task_cmd) < 0); - if (dev->transport->tmr_notify) dev->transport->tmr_notify(dev, TMR_ABORT_TASK, &aborted_list); @@ -234,6 +218,7 @@ static void core_tmr_drain_tmr_list( } list_move_tail(&tmr_p->tmr_list, &drain_tmr_list); + tmr_p->tmr_dev = NULL; } spin_unlock_irqrestore(&dev->se_tmr_lock, flags); -- cgit v1.2.3