linux-stable.git/drivers/target, branch v3.18.41

iscsi-target: Fix panic when adding second TCP connection to iSCSI session

2016-08-22T16:23:16+00:00

[ Upstream commit 8abc718de6e9e52d8a6bfdb735060554aeae25e4 ]

In MC/S scenario, the conn->sess has been set NULL in
iscsi_login_non_zero_tsih_s1 when the second connection comes here,
then kernel panic.

The conn->sess will be assigned in iscsi_login_non_zero_tsih_s2. So
we should check whether it's NULL before calling.

Signed-off-by: Feng Li 
Tested-by: Sumit Rai 
Cc: stable@vger.kernel.org # 3.14+
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Sasha Levin

target: Fix race between iscsi-target connection shutdown + ABORT_TASK

2016-08-22T16:23:14+00:00

[ Upstream commit 064cdd2d91c2805d788876082f31cc63506f22c3 ]

This patch fixes a race in iscsit_release_commands_from_conn() ->
iscsit_free_cmd() -> transport_generic_free_cmd() + wait_for_tasks=1,
where CMD_T_FABRIC_STOP could end up being set after the final
kref_put() is called from core_tmr_abort_task() context.

This results in transport_generic_free_cmd() blocking indefinately
on se_cmd->cmd_wait_comp, because the target_release_cmd_kref()
check for CMD_T_FABRIC_STOP returns false.

To address this bug, make iscsit_release_commands_from_conn()
do list_splice and set CMD_T_FABRIC_STOP early while holding
iscsi_conn->cmd_lock.  Also make iscsit_aborted_task() only
remove iscsi_cmd_t if CMD_T_FABRIC_STOP has not already been
set.

Finally in target_release_cmd_kref(), only honor fabric_stop
if CMD_T_ABORTED has been set.

Cc: Mike Christie 
Cc: Quinn Tran 
Cc: Himanshu Madhani 
Cc: Christoph Hellwig 
Cc: Hannes Reinecke 
Cc: stable@vger.kernel.org # 3.14+
Tested-by: Nicholas Bellinger 
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Sasha Levin

target: Fix missing complete during ABORT_TASK + CMD_T_FABRIC_STOP

2016-08-22T16:23:13+00:00

[ Upstream commit 5e2c956b8aa24d4f33ff7afef92d409eed164746 ]

During transport_generic_free_cmd() with a concurrent TMR
ABORT_TASK and shutdown CMD_T_FABRIC_STOP bit set, the
caller will be blocked on se_cmd->cmd_wait_stop completion
until the final kref_put() -> target_release_cmd_kref()
has been invoked to call complete().

However, when ABORT_TASK is completed with FUNCTION_COMPLETE
in core_tmr_abort_task(), the aborted se_cmd will have already
been removed from se_sess->sess_cmd_list via list_del_init().

This results in target_release_cmd_kref() hitting the
legacy list_empty() == true check, invoking ->release_cmd()
but skipping complete() to wakeup se_cmd->cmd_wait_stop
blocked earlier in transport_generic_free_cmd() code.

To address this bug, it's safe to go ahead and drop the
original list_empty() check so that fabric_stop invokes
the complete() as expected, since list_del_init() can
safely be used on a empty list.

Cc: Mike Christie 
Cc: Quinn Tran 
Cc: Himanshu Madhani 
Cc: Christoph Hellwig 
Cc: Hannes Reinecke 
Cc: stable@vger.kernel.org # 3.14+
Tested-by: Nicholas Bellinger 
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Sasha Levin

target: Fix target_release_cmd_kref shutdown comp leak

2016-04-18T12:49:37+00:00

[ Upstream commit 5e47f1985d7107331c3f64fb3ec83d66fd73577e ]

This patch fixes an active I/O shutdown bug for fabric
drivers using target_wait_for_sess_cmds(), where se_cmd
descriptor shutdown would result in hung tasks waiting
indefinitely for se_cmd->cmd_wait_comp to complete().

To address this bug, drop the incorrect list_del_init()
usage in target_wait_for_sess_cmds() and always complete()
during se_cmd target_release_cmd_kref() put, in order to
let caller invoke the final fabric release callback
into se_cmd->se_tfo->release_cmd() code.

Reported-by: Himanshu Madhani 
Tested-by: Himanshu Madhani 
Signed-off-by: Himanshu Madhani 
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Sasha Levin

target: Drop incorrect ABORT_TASK put for completed commands

2016-03-22T15:11:11+00:00

[ Upstream commit 7f54ab5ff52fb0b91569bc69c4a6bc5cac1b768d ]

This patch fixes a recent ABORT_TASK regression associated
with commit febe562c, where a left-over target_put_sess_cmd()
would still be called when __target_check_io_state() detected
a command has already been completed, and explicit ABORT must
be avoided.

Note commit febe562c dropped the local kref_get_unless_zero()
check in core_tmr_abort_task(), but did not drop this extra
corresponding target_put_sess_cmd() in the failure path.

So go ahead and drop this now bogus target_put_sess_cmd(),
and avoid this potential use-after-free.

Reported-by: Dan Lane 
Cc: Quinn Tran 
Cc: Himanshu Madhani 
Cc: Sagi Grimberg 
Cc: Christoph Hellwig 
Cc: Hannes Reinecke 
Cc: Andy Grover 
Cc: Mike Christie 
Cc: stable@vger.kernel.org # 3.14+
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Sasha Levin

target: Fix race with SCF_SEND_DELAYED_TAS handling

2016-03-06T03:13:45+00:00

commit 310d3d314be7f0a84011ebdc4bdccbcae9755a87 upstream.

This patch fixes a race between setting of SCF_SEND_DELAYED_TAS
in transport_send_task_abort(), and check of the same bit in
transport_check_aborted_status().

It adds a __transport_check_aborted_status() version that is
used by target_execute_cmd() when se_cmd->t_state_lock is
held, and a transport_check_aborted_status() wrapper for
all other existing callers.

Also, it handles the case where the check happens before
transport_send_task_abort() gets called.  For this, go
ahead and set SCF_SEND_DELAYED_TAS early when necessary,
and have transport_send_task_abort() send the abort.

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 remote-port TMR ABORT + se_cmd fabric stop

2016-03-06T03:13:44+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 TAS handling for multi-session se_node_acls

2016-03-06T03:13:43+00:00

commit ebde1ca5a908b10312db4ecd7553e3ba039319ab upstream.

This patch fixes a bug in TMR task aborted status (TAS)
handling when multiple sessions are connected to the
same target WWPN endpoint and se_node_acl descriptor,
resulting in TASK_ABORTED status to not be generated
for aborted se_cmds on the remote port.

This is due to core_tmr_handle_tas_abort() incorrectly
comparing se_node_acl instead of se_session, for which
the multi-session case is expected to be sharing the
same se_node_acl.

Instead, go ahead and update core_tmr_handle_tas_abort()
to compare tmr_sess + cmd->se_sess in order to determine
if the LUN_RESET was received on a different I_T nexus,
and TASK_ABORTED status response needs to be generated.

Reviewed-by: Christoph Hellwig 
Cc: Quinn Tran 
Cc: Himanshu Madhani 
Cc: Sagi Grimberg 
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

2016-03-06T03:13:43+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 COMPARE_AND_WRITE non zero SGL offset data corruption

2016-03-06T03:13:43+00:00

[ Upstream commit d94e5a61357a04938ce14d6033b4d33a3c5fd780 ]

target_core_sbc's compare_and_write functionality suffers from taking
data at the wrong memory location when writing a CAW request to disk
when a SGL offset is non-zero.

This can happen with loopback and vhost-scsi fabric drivers when
SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC is used to map existing user-space
SGL memory into COMPARE_AND_WRITE READ/WRITE payload buffers.

Given the following sample LIO subtopology,

% targetcli ls /loopback/
o- loopback ................................. [1 Target]
  o- naa.6001405ebb8df14a ....... [naa.60014059143ed2b3]
    o- luns ................................... [2 LUNs]
      o- lun0 ................ [iblock/ram0 (/dev/ram0)]
      o- lun1 ................ [iblock/ram1 (/dev/ram1)]
% lsscsi -g
[3:0:1:0]    disk    LIO-ORG  IBLOCK           4.0   /dev/sdc   /dev/sg3
[3:0:1:1]    disk    LIO-ORG  IBLOCK           4.0   /dev/sdd   /dev/sg4

the following bug can be observed in Linux 4.3 and 4.4~rc1:

% perl -e 'print chr$_ for 0..255,reverse 0..255' >rand
% perl -e 'print "\0" x 512' >zero
% cat rand >/dev/sdd
% sg_compare_and_write -i rand -D zero --lba 0 /dev/sdd
% sg_compare_and_write -i zero -D rand --lba 0 /dev/sdd
Miscompare reported
% hexdump -Cn 512 /dev/sdd
00000000  0f 0e 0d 0c 0b 0a 09 08  07 06 05 04 03 02 01 00
00000010  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
*
00000200

Rather than writing all-zeroes as instructed with the -D file, it
corrupts the data in the sector by splicing some of the original
bytes in. The page of the first entry of cmd->t_data_sg includes the
CDB, and sg->offset is set to a position past the CDB. I presume that
sg->offset is also the right choice to use for subsequent sglist
members.

Signed-off-by: Jan Engelhardt 
Tested-by: Douglas Gilbert 
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Sasha Levin