kernel/linux.git/include/target/target_core_base.h, branch v4.4.239

target: Avoid early CMD_T_PRE_EXECUTE failures during ABORT_TASK

2018-01-17T08:35:31+00:00

commit 1c21a48055a67ceb693e9c2587824a8de60a217c upstream. This patch fixes bug where early se_cmd exceptions that occur before backend execution can result in use-after-free if/when a subsequent ABORT_TASK occurs for the same tag. Since an early se_cmd exception will have had se_cmd added to se_session->sess_cmd_list via target_get_sess_cmd(), it will not have CMD_T_COMPLETE set by the usual target_complete_cmd() backend completion path. This causes a subsequent ABORT_TASK + __target_check_io_state() to signal ABORT_TASK should proceed. As core_tmr_abort_task() executes, it will bring the outstanding se_cmd->cmd_kref count down to zero releasing se_cmd, after se_cmd has already been queued with error status into fabric driver response path code. To address this bug, introduce a CMD_T_PRE_EXECUTE bit that is set at target_get_sess_cmd() time, and cleared immediately before backend driver dispatch in target_execute_cmd() once CMD_T_ACTIVE is set. Then, check CMD_T_PRE_EXECUTE within __target_check_io_state() to determine when an early exception has occured, and avoid aborting this se_cmd since it will have already been queued into fabric driver response path code. Reported-by: Donald White Cc: Donald White Cc: Mike Christie Cc: Hannes Reinecke Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman

target: fix ALUA transition timeout handling

2017-12-20T09:04:57+00:00

[ Upstream commit d7175373f2745ed4abe5b388d5aabd06304f801e ] The implicit transition time tells initiators the min time to wait before timing out a transition. We currently schedule the transition to occur in tg_pt_gp_implicit_trans_secs seconds so there is no room for delays. If core_alua_do_transition_tg_pt_work->core_alua_update_tpg_primary_metadata needs to write out info to a remote file, then the initiator can easily time out the operation. Signed-off-by: Mike Christie Signed-off-by: Nicholas Bellinger Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

target/iscsi: Fix iSCSI task reassignment handling

2017-11-18T10:11:07+00:00

commit 59b6986dbfcdab96a971f9663221849de79a7556 upstream. Allocate a task management request structure for all task management requests, including task reassignment. This change avoids that the se_tmr->response assignment dereferences an uninitialized se_tmr pointer. Reported-by: Moshe David Signed-off-by: Bart Van Assche Reviewed-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Cc: Moshe David Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman

target: Avoid mappedlun symlink creation during lun shutdown

2017-08-11T16:08:49+00:00

commit 49cb77e297dc611a1b795cfeb79452b3002bd331 upstream. This patch closes a race between se_lun deletion during configfs unlink in target_fabric_port_unlink() -> core_dev_del_lun() -> core_tpg_remove_lun(), when transport_clear_lun_ref() blocks waiting for percpu_ref RCU grace period to finish, but a new NodeACL mappedlun is added before the RCU grace period has completed. This can happen in target_fabric_mappedlun_link() because it only checks for se_lun->lun_se_dev, which is not cleared until after transport_clear_lun_ref() percpu_ref RCU grace period finishes. This bug originally manifested as NULL pointer dereference OOPsen in target_stat_scsi_att_intr_port_show_attr_dev() on v4.1.y code, because it dereferences lun->lun_se_dev without a explicit NULL pointer check. In post v4.1 code with target-core RCU conversion, the code in target_stat_scsi_att_intr_port_show_attr_dev() no longer uses se_lun->lun_se_dev, but the same race still exists. To address the bug, go ahead and set se_lun>lun_shutdown as early as possible in core_tpg_remove_lun(), and ensure new NodeACL mappedlun creation in target_fabric_mappedlun_link() fails during se_lun shutdown. Reported-by: James Shen Cc: James Shen Tested-by: James Shen Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman

target: Fix NULL dereference during LUN lookup + active I/O shutdown

2017-03-15T01:57:14+00:00

commit bd4e2d2907fa23a11d46217064ecf80470ddae10 upstream. When transport_clear_lun_ref() is shutting down a se_lun via configfs with new I/O in-flight, it's possible to trigger a NULL pointer dereference in transport_lookup_cmd_lun() due to the fact percpu_ref_get() doesn't do any __PERCPU_REF_DEAD checking before incrementing lun->lun_ref.count after lun->lun_ref has switched to atomic_t mode. This results in a NULL pointer dereference as LUN shutdown code in core_tpg_remove_lun() continues running after the existing ->release() -> core_tpg_lun_ref_release() callback completes, and clears the RCU protected se_lun->lun_se_dev pointer. During the OOPs, the state of lun->lun_ref in the process which triggered the NULL pointer dereference looks like the following on v4.1.y stable code: struct se_lun { lun_link_magic = 4294932337, lun_status = TRANSPORT_LUN_STATUS_FREE, ..... lun_se_dev = 0x0, lun_sep = 0x0, ..... lun_ref = { count = { counter = 1 }, percpu_count_ptr = 3, release = 0xffffffffa02fa1e0 , confirm_switch = 0x0, force_atomic = false, rcu = { next = 0xffff88154fa1a5d0, func = 0xffffffff8137c4c0 } } } To address this bug, use percpu_ref_tryget_live() to ensure once __PERCPU_REF_DEAD is visable on all CPUs and ->lun_ref has switched to atomic_t, all new I/Os will fail to obtain a new lun->lun_ref reference. Also use an explicit percpu_ref_kill_and_confirm() callback to block on ->lun_ref_comp to allow the first stage and associated RCU grace period to complete, and then block on ->lun_ref_shutdown waiting for the final percpu_ref_put() to drop the last reference via transport_lun_remove_cmd() before continuing with core_tpg_remove_lun() shutdown. Reported-by: Rob Millner Tested-by: Rob Millner Cc: Rob Millner Tested-by: Vaibhav Tandon Cc: Vaibhav Tandon Tested-by: Bryant G. Ly Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman

target: Fix multi-session dynamic se_node_acl double free OOPs

2017-03-12T05:37:27+00:00

commit 01d4d673558985d9a118e1e05026633c3e2ade9b upstream. This patch addresses a long-standing bug with multi-session (eg: iscsi-target + iser-target) se_node_acl dynamic free withini transport_deregister_session(). This bug is caused when a storage endpoint is configured with demo-mode (generate_node_acls = 1 + cache_dynamic_acls = 1) initiators, and initiator login creates a new dynamic node acl and attaches two sessions to it. After that, demo-mode for the storage instance is disabled via configfs (generate_node_acls = 0 + cache_dynamic_acls = 0) and the existing dynamic acl is never converted to an explicit ACL. The end result is dynamic acl resources are released twice when the sessions are shutdown in transport_deregister_session(). If the storage instance is not changed to disable demo-mode, or the dynamic acl is converted to an explict ACL, or there is only a single session associated with the dynamic ACL, the bug is not triggered. To address this big, move the release of dynamic se_node_acl memory into target_complete_nacl() so it's only freed once when se_node_acl->acl_kref reaches zero. (Drop unnecessary list_del_init usage - HCH) Reported-by: Rob Millner Tested-by: Rob Millner Cc: Rob Millner Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman

target: Make EXTENDED_COPY 0xe4 failure return COPY TARGET DEVICE NOT REACHABLE

2016-10-28T07:01:36+00:00

commit 449a137846c84829a328757cd21fd9ca65c08519 upstream. This patch addresses a bug where EXTENDED_COPY across multiple LUNs results in a CHECK_CONDITION when the source + destination are not located on the same physical node. ESX Host environments expect sense COPY_ABORTED w/ COPY TARGET DEVICE NOT REACHABLE to be returned when this occurs, in order to signal fallback to local copy method. As described in section 6.3.3 of spc4r22: "If it is not possible to complete processing of a segment because the copy manager is unable to establish communications with a copy target device, because the copy target device does not respond to INQUIRY, or because the data returned in response to INQUIRY indicates an unsupported logical unit, then the EXTENDED COPY command shall be terminated with CHECK CONDITION status, with the sense key set to COPY ABORTED, and the additional sense code set to COPY TARGET DEVICE NOT REACHABLE." Tested on v4.1.y with ESX v5.5u2+ with BlockCopy across multiple nodes. Reported-by: Nixon Vincent Tested-by: Nixon Vincent Cc: Nixon Vincent Tested-by: Dinesh Israni Signed-off-by: Dinesh Israni Cc: Dinesh Israni Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman

target: Fix ordered task CHECK_CONDITION early exception handling

2016-08-20T16:09:26+00:00

commit 410c29dfbfdf73d0d0b5d14a21868ab038eca703 upstream. If a Simple command is sent with a failure, target_setup_cmd_from_cdb returns with TCM_UNSUPPORTED_SCSI_OPCODE or TCM_INVALID_CDB_FIELD. So in the cases where target_setup_cmd_from_cdb returns an error, we never get far enough to call target_execute_cmd to increment simple_cmds. Since simple_cmds isn't incremented, the result of the failure from target_setup_cmd_from_cdb causes transport_generic_request_failure to decrement simple_cmds, due to call to transport_complete_task_attr. With this dev->simple_cmds or dev->dev_ordered_sync is now -1, not 0. So when a subsequent command with an Ordered Task is sent, it causes a hang, since dev->simple_cmds is at -1. Tested-by: Bryant G. Ly Signed-off-by: Bryant G. Ly Tested-by: Michael Cyr Signed-off-by: Michael Cyr Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman

target: Fix remote-port TMR ABORT + se_cmd fabric stop

2016-03-03T23:07:27+00:00

commit 0f4a943168f31d29a1701908931acaba518b131a upstream. To address the bug where fabric driver level shutdown of se_cmd occurs at the same time when TMR CMD_T_ABORTED is happening resulting in a -1 ->cmd_kref, this patch adds a CMD_T_FABRIC_STOP bit that is used to determine when TMR + driver I_T nexus shutdown is happening concurrently. It changes target_sess_cmd_list_set_waiting() to obtain se_cmd->cmd_kref + set CMD_T_FABRIC_STOP, and drop local reference in target_wait_for_sess_cmds() and invoke extra target_put_sess_cmd() during Task Aborted Status (TAS) when necessary. Also, it adds a new target_wait_free_cmd() wrapper around transport_wait_for_tasks() for the special case within transport_generic_free_cmd() to set CMD_T_FABRIC_STOP, and is now aware of CMD_T_ABORTED + CMD_T_TAS status bits to know when an extra transport_put_cmd() during TAS is required. Note transport_generic_free_cmd() is expected to block on cmd->cmd_wait_comp in order to follow what iscsi-target expects during iscsi_conn context se_cmd shutdown. Cc: Quinn Tran Cc: Himanshu Madhani Cc: Sagi Grimberg Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Andy Grover Cc: Mike Christie Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman

target: Fix LUN_RESET active I/O handling for ACK_KREF

2016-03-03T23:07:27+00:00

commit febe562c20dfa8f33bee7d419c6b517986a5aa33 upstream. This patch fixes a NULL pointer se_cmd->cmd_kref < 0 refcount bug during TMR LUN_RESET with active se_cmd I/O, that can be triggered during se_cmd descriptor shutdown + release via core_tmr_drain_state_list() code. To address this bug, add common __target_check_io_state() helper for ABORT_TASK + LUN_RESET w/ CMD_T_COMPLETE checking, and set CMD_T_ABORTED + obtain ->cmd_kref for both cases ahead of last target_put_sess_cmd() after TFO->aborted_task() -> transport_cmd_finish_abort() callback has completed. It also introduces SCF_ACK_KREF to determine when transport_cmd_finish_abort() needs to drop the second extra reference, ahead of calling target_put_sess_cmd() for the final kref_put(&se_cmd->cmd_kref). It also updates transport_cmd_check_stop() to avoid holding se_cmd->t_state_lock while dropping se_cmd device state via target_remove_from_state_list(), now that core_tmr_drain_state_list() is holding the se_device lock while checking se_cmd state from within TMR logic. Finally, move transport_put_cmd() release of SGL + TMR + extended CDB memory into target_free_cmd_mem() in order to avoid potential resource leaks in TMR ABORT_TASK + LUN_RESET code-paths. Also update target_release_cmd_kref() accordingly. Reviewed-by: Quinn Tran Cc: Himanshu Madhani Cc: Sagi Grimberg Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Andy Grover Cc: Mike Christie Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman