linux-stable.git/include/target/target_core_base.h, branch linux-4.1.y

target: Avoid mappedlun symlink creation during lun shutdown

2017-12-06T23:25:56+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: Sasha Levin

target/iscsi: Fix iSCSI task reassignment handling

2017-12-06T23:25:56+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: Sasha Levin

target: Fix multi-session dynamic se_node_acl double free OOPs

2017-12-06T23:25:56+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: Sasha Levin

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

2016-03-06T03:11:42+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: Sasha Levin

target: Fix LUN_RESET active I/O handling for ACK_KREF

2016-03-06T03:11:41+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: Sasha Levin

target: Fix race for SCF_COMPARE_AND_WRITE_POST checking

2016-03-06T03:11:41+00:00

[ Upstream commit 057085e522f8bf94c2e691a5b76880f68060f8ba ]

This patch addresses a race + use after free where the first
stage of COMPARE_AND_WRITE in compare_and_write_callback()
is rescheduled after the backend sends the secondary WRITE,
resulting in second stage compare_and_write_post() callback
completing in target_complete_ok_work() before the first
can return.

Because current code depends on checking se_cmd->se_cmd_flags
after return from se_cmd->transport_complete_callback(),
this results in first stage having SCF_COMPARE_AND_WRITE_POST
set, which incorrectly falls through into second stage CAW
processing code, eventually triggering a NULL pointer
dereference due to use after free.

To address this bug, pass in a new *post_ret parameter into
se_cmd->transport_complete_callback(), and depend upon this
value instead of ->se_cmd_flags to determine when to return
or fall through into ->queue_status() code for CAW.

Cc: Sagi Grimberg 
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Sasha Levin

target: Ensure sess_prot_type is saved across session restart

2015-04-16T05:46:30+00:00

The following incremental patch saves the current sess_prot_type into
se_node_acl, and will always reset sess_prot_type if a previous saved
value exists.  So the PI setting for the fabric's session with backend
devices not supporting PI is persistent across session restart.

(Fix se_node_acl dereference for discovery sessions - DanCarpenter)

Reviewed-by: Martin Petersen 
Reviewed-by: Sagi Grimberg 
Signed-off-by: Nicholas Bellinger

target: Remove the unused flag SCF_ACK_KREF

2015-04-14T19:37:39+00:00

The flag SCF_ACK_KREF is only set but never tested. Hence remove
this flag.

Signed-off-by: Bart Van Assche 
Cc: Christoph Hellwig 
Signed-off-by: Nicholas Bellinger

target: Fix COMPARE_AND_WRITE with SG_TO_MEM_NOALLOC handling

2015-04-14T19:37:38+00:00

This patch fixes a bug for COMPARE_AND_WRITE handling with
fabrics using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC.

It adds the missing allocation for cmd->t_bidi_data_sg within
transport_generic_new_cmd() that is used by COMPARE_AND_WRITE
for the initial READ payload, even if the fabric is already
providing a pre-allocated buffer for cmd->t_data_sg.

Also, fix zero-length COMPARE_AND_WRITE handling within the
compare_and_write_callback() and target_complete_ok_work()
to queue the response, skipping the initial READ.

This fixes COMPARE_AND_WRITE emulation with loopback, vhost,
and xen-backend fabric drivers using SG_TO_MEM_NOALLOC.

Reported-by: Christoph Hellwig 
Cc: Christoph Hellwig 
Cc:  # v3.12+
Signed-off-by: Nicholas Bellinger

target: simplify the target template registration API

2015-04-14T19:28:41+00:00

Instead of calling target_fabric_configfs_init() +
target_fabric_configfs_register() / target_fabric_configfs_deregister()
target_fabric_configfs_free() from every target driver, rewrite the API
so that we have simple register/unregister functions that operate on
a const operations vector.

This patch also fixes a memory leak in several target drivers. Several
target drivers namely called target_fabric_configfs_deregister()
without calling target_fabric_configfs_free().

A large part of this patch is based on earlier changes from
Bart Van Assche .

(v2: Add a new TF_CIT_SETUP_DRV macro so that the core configfs code
can declare attributes as either core only or for drivers)

Signed-off-by: Christoph Hellwig 
Signed-off-by: Nicholas Bellinger