linux-stable.git/drivers/target, branch v3.12.64

target: Fix target_release_cmd_kref shutdown comp leak

2016-04-11T14:44:24+00:00

commit 5e47f1985d7107331c3f64fb3ec83d66fd73577e upstream.

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.

[3.12 backport: we have only list_del]

Reported-by: Himanshu Madhani 
Tested-by: Himanshu Madhani 
Signed-off-by: Himanshu Madhani 
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Jiri Slaby

target: fix COMPARE_AND_WRITE non zero SGL offset data corruption

2016-03-03T11:45:57+00:00

commit d94e5a61357a04938ce14d6033b4d33a3c5fd780 upstream.

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: Jiri Slaby

target: Fix race for SCF_COMPARE_AND_WRITE_POST checking

2016-03-03T11:45:57+00:00

commit 057085e522f8bf94c2e691a5b76880f68060f8ba upstream.

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: Jiri Slaby

iscsi-target: Fix potential dead-lock during node acl delete

2016-02-24T09:23:27+00:00

commit 26a99c19f810b2593410899a5b304b21b47428a6 upstream.

This patch is a iscsi-target specific bug-fix for a dead-lock
that can occur during explicit struct se_node_acl->acl_group
se_session deletion via configfs rmdir(2), when iscsi-target
time2retain timer is still active.

It changes iscsi-target to obtain se_portal_group->session_lock
internally using spin_in_locked() to check for the specific
se_node_acl configfs shutdown rmdir(2) case.

Note this patch is intended for stable, and the subsequent
v4.5-rc patch converts target_core_tpg.c to use proper
se_sess->sess_kref reference counting for both se_node_acl
deletion + se_node_acl->queue_depth se_session restart.

Reported-by:: Sagi Grimberg 
Cc: Christoph Hellwig 
Cc: Hannes Reinecke 
Cc: Andy Grover 
Cc: Mike Christie 
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Jiri Slaby

iscsi-target: Fix rx_login_comp hang after login failure

2016-02-24T09:23:25+00:00

commit ca82c2bded29b38d36140bfa1e76a7bbfcade390 upstream.

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 e54198657b65625085834847ab6271087323ffea
  Author: Nicholas Bellinger 
  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 
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Jiri Slaby

target/stat: print full t10_wwn.model buffer

2016-01-05T17:26:33+00:00

commit 8f90353950b2da8d877c6ac3dde5e1109257a117 upstream.

Cut 'n paste error saw it only process sizeof(t10_wwn.vendor) characters.

Signed-off-by: David Disseldorp 
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Jiri Slaby

iscsi-target: Fix iscsit_start_kthreads failure OOPs

2015-08-25T14:56:54+00:00

commit e54198657b65625085834847ab6271087323ffea upstream.

This patch fixes a regression introduced with the following commit
in v4.0-rc1 code, where a iscsit_start_kthreads() failure triggers
a NULL pointer dereference OOPs:

    commit 88dcd2dab5c23b1c9cfc396246d8f476c872f0ca
    Author: Nicholas Bellinger 
    Date:   Thu Feb 26 22:19:15 2015 -0800

        iscsi-target: Convert iscsi_thread_set usage to kthread.h

To address this bug, move iscsit_start_kthreads() immediately
preceeding the transmit of last login response, before signaling
a successful transition into full-feature-phase within existing
iscsi_target_do_tx_login_io() logic.

This ensures that no target-side resource allocation failures can
occur after the final login response has been successfully sent.

Also, it adds a iscsi_conn->rx_login_comp to allow the RX thread
to sleep to prevent other socket related failures until the final
iscsi_post_login_handler() call is able to complete.

Cc: Sagi Grimberg 
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Jiri Slaby

iscsi-target: Fix iser explicit logout TX kthread leak

2015-08-19T06:36:44+00:00

commit 007d038bdf95ccfe2491d0078be54040d110fd06 upstream.

This patch fixes a regression introduced with the following commit
in v4.0-rc1 code, where an explicit iser-target logout would result
in ->tx_thread_active being incorrectly cleared by the logout post
handler, and subsequent TX kthread leak:

    commit 88dcd2dab5c23b1c9cfc396246d8f476c872f0ca
    Author: Nicholas Bellinger 
    Date:   Thu Feb 26 22:19:15 2015 -0800

        iscsi-target: Convert iscsi_thread_set usage to kthread.h

To address this bug, change iscsit_logout_post_handler_closesession()
and iscsit_logout_post_handler_samecid() to only cmpxchg() on
->tx_thread_active for traditional iscsi/tcp connections.

This is required because iscsi/tcp connections are invoking logout
post handler logic directly from TX kthread context, while iser
connections are invoking logout post handler logic from a seperate
workqueue context.

Cc: Sagi Grimberg 
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Jiri Slaby

iscsi-target: Fix use-after-free during TPG session shutdown

2015-08-19T06:36:44+00:00

commit 417c20a9bdd1e876384127cf096d8ae8b559066c upstream.

This patch fixes a use-after-free bug in iscsit_release_sessions_for_tpg()
where se_portal_group->session_lock was incorrectly released/re-acquired
while walking the active se_portal_group->tpg_sess_list.

The can result in a NULL pointer dereference when iscsit_close_session()
shutdown happens in the normal path asynchronously to this code, causing
a bogus dereference of an already freed list entry to occur.

To address this bug, walk the session list checking for the same state
as before, but move entries to a local list to avoid dropping the lock
while walking the active list.

As before, signal using iscsi_session->session_restatement=1 for those
list entries to be released locally by iscsit_free_session() code.

Reported-by: Sunilkumar Nadumuttlu 
Cc: Sunilkumar Nadumuttlu 
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Jiri Slaby

iscsi-target: Convert iscsi_thread_set usage to kthread.h

2015-08-04T14:52:27+00:00

commit 88dcd2dab5c23b1c9cfc396246d8f476c872f0ca upstream.

This patch converts iscsi-target code to use modern kthread.h API
callers for creating RX/TX threads for each new iscsi_conn descriptor,
and releasing associated RX/TX threads during connection shutdown.

This is done using iscsit_start_kthreads() -> kthread_run() to start
new kthreads from within iscsi_post_login_handler(), and invoking
kthread_stop() from existing iscsit_close_connection() code.

Also, convert iscsit_logout_post_handler_closesession() code to use
cmpxchg when determing when iscsit_cause_connection_reinstatement()
needs to sleep waiting for completion.

Reported-by: Sagi Grimberg 
Tested-by: Sagi Grimberg 
Cc: Slava Shwartsman 
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Jiri Slaby