diff options
author | Dmitry Bogdanov <d.bogdanov@yadro.com> | 2021-10-18 16:57:53 +0300 |
---|---|---|
committer | Martin K. Petersen <martin.petersen@oracle.com> | 2021-10-26 23:15:23 -0400 |
commit | 12b6fcd0ea7f3cb7c3b34668fc678779924123ae (patch) | |
tree | b5ce8eaf809a0e0082498ab7135ae0e5cab87d25 /drivers/target | |
parent | 83c3a7beaef7fd261c190b69f6be6337f251bf16 (diff) |
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 <r.bolshakov@yadro.com>
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Dmitry Bogdanov <d.bogdanov@yadro.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/target')
-rw-r--r-- | drivers/target/target_core_tmr.c | 17 | ||||
-rw-r--r-- | drivers/target/target_core_transport.c | 30 |
2 files changed, 24 insertions, 23 deletions
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); diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 4a2e749eb182..7838dc20f713 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -676,6 +676,21 @@ static void target_remove_from_state_list(struct se_cmd *cmd) spin_unlock_irqrestore(&dev->queues[cmd->cpuid].lock, flags); } +static void target_remove_from_tmr_list(struct se_cmd *cmd) +{ + struct se_device *dev = NULL; + unsigned long flags; + + if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB) + dev = cmd->se_tmr_req->tmr_dev; + + if (dev) { + spin_lock_irqsave(&dev->se_tmr_lock, flags); + if (cmd->se_tmr_req->tmr_dev) + list_del_init(&cmd->se_tmr_req->tmr_list); + spin_unlock_irqrestore(&dev->se_tmr_lock, flags); + } +} /* * This function is called by the target core after the target core has * finished processing a SCSI command or SCSI TMF. Both the regular command @@ -687,13 +702,6 @@ static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd) { unsigned long flags; - target_remove_from_state_list(cmd); - - /* - * Clear struct se_cmd->se_lun before the handoff to FE. - */ - cmd->se_lun = NULL; - spin_lock_irqsave(&cmd->t_state_lock, flags); /* * Determine if frontend context caller is requesting the stopping of @@ -728,8 +736,16 @@ static void transport_lun_remove_cmd(struct se_cmd *cmd) if (!lun) return; + target_remove_from_state_list(cmd); + target_remove_from_tmr_list(cmd); + if (cmpxchg(&cmd->lun_ref_active, true, false)) percpu_ref_put(&lun->lun_ref); + + /* + * Clear struct se_cmd->se_lun before the handoff to FE. + */ + cmd->se_lun = NULL; } static void target_complete_failure_work(struct work_struct *work) |