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  1. 06 Mar, 2016 5 commits
    • Nicholas Bellinger's avatar
      target: Fix TAS handling for multi-session se_node_acls · 84f48a25
      Nicholas Bellinger authored 
      commit ebde1ca5 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: default avatarChristoph Hellwig <hch@lst.de>
Cc: Quinn Tran <quinn.tran@qlogic.com>
Cc: Himanshu Madhani <himanshu.madhani@qlogic.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: Mike Christie <mchristi@redhat.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      84f48a25
    • Nicholas Bellinger's avatar
      target: Fix LUN_RESET active I/O handling for ACK_KREF · 61c88d64
      Nicholas Bellinger authored 
      commit febe562c 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: default avatarQuinn Tran <quinn.tran@qlogic.com>
Cc: Himanshu Madhani <himanshu.madhani@qlogic.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: Mike Christie <mchristi@redhat.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      61c88d64
    • Jan Engelhardt's avatar
      target: fix COMPARE_AND_WRITE non zero SGL offset data corruption · f66800d3
      Jan Engelhardt authored 
      [ Upstream commit d94e5a61 ]

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: default avatarJan Engelhardt <jengelh@netitwork.de>
Tested-by: default avatarDouglas Gilbert <dgilbert@interlog.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      f66800d3
    • Nicholas Bellinger's avatar
      target: Fix race for SCF_COMPARE_AND_WRITE_POST checking · 88343147
      Nicholas Bellinger authored 
      [ Upstream commit 057085e5 ]

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 <sagig@mellanox.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      88343147
    • Nicholas Bellinger's avatar
      iscsi-target: Fix rx_login_comp hang after login failure · eebeb74b
      Nicholas Bellinger authored 
      [ Upstream commit ca82c2bd ]

This patch addresses a case where iscsi_target_do_tx_login_io()
fails sending the last login response PDU, after the RX/TX
threads have already been started.

The case centers around iscsi_target_rx_thread() not invoking
allow_signal(SIGINT) before the send_sig(SIGINT, ...) occurs
from the failure path, resulting in RX thread hanging
indefinately on iscsi_conn->rx_login_comp.

Note this bug is a regression introduced by:

  commit e5419865
  Author: Nicholas Bellinger <nab@linux-iscsi.org>
  Date:   Wed Jul 22 23:14:19 2015 -0700

      iscsi-target: Fix iscsit_start_kthreads failure OOPs

To address this bug, complete ->rx_login_complete for good
measure in the failure path, and immediately return from
RX thread context if connection state did not actually reach
full feature phase (TARG_CONN_STATE_LOGGED_IN).

Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      eebeb74b
  3. 04 Mar, 2016 35 commits
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