linux-stable.git/drivers/target, branch v3.7.4 Linux kernel stable tree target: Add link_magic for fabric allow_link destination target_items 2013-01-21T19:44:44+00:00 Nicholas Bellinger nab@linux-iscsi.org 2012-12-05T07:43:57+00:00 fdf9d862969f1be18814273b03fb9497ec2dbdae commit 0ff8754981261a80f4b77db2536dfea92c2d4539 upstream. This patch adds [dev,lun]_link_magic value assignment + checks within generic target_fabric_port_link() and target_fabric_mappedlun_link() code to ensure destination config_item *target_item sent from configfs_symlink() -> config_item_operations->allow_link() is the underlying se_device->dev_group and se_lun->lun_group that we expect to symlink. Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: CAI Qian <caiqian@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 0ff8754981261a80f4b77db2536dfea92c2d4539 upstream.

This patch adds [dev,lun]_link_magic value assignment + checks within generic
target_fabric_port_link() and target_fabric_mappedlun_link() code to ensure
destination config_item *target_item sent from configfs_symlink() ->
config_item_operations->allow_link() is the underlying se_device->dev_group
and se_lun->lun_group that we expect to symlink.

Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
target: Release se_cmd when LUN lookup fails for TMR 2013-01-21T19:44:33+00:00 Roland Dreier roland@purestorage.com 2013-01-02T20:47:59+00:00 c67507852d0777a8e616fb7c40da71cc40c328b3 commit 5a3b6fc0092c5f8dee7820064ee54d2631d48573 upstream. When transport_lookup_tmr_lun() fails and we return a task management response from target_complete_tmr_failure(), we need to call transport_cmd_check_stop_to_fabric() to release the last ref to the cmd after calling se_tfo->queue_tm_rsp(), or else we will never remove the failed TMR from the session command list (and we'll end up waiting forever when trying to tear down the session). (nab: Fix minor compile breakage) Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 5a3b6fc0092c5f8dee7820064ee54d2631d48573 upstream.

When transport_lookup_tmr_lun() fails and we return a task management
response from target_complete_tmr_failure(), we need to call
transport_cmd_check_stop_to_fabric() to release the last ref to the
cmd after calling se_tfo->queue_tm_rsp(), or else we will never remove
the failed TMR from the session command list (and we'll end up waiting
forever when trying to tear down the session).

(nab: Fix minor compile breakage)

Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
target: Fix use-after-free in LUN RESET handling 2013-01-21T19:44:33+00:00 Roland Dreier roland@purestorage.com 2013-01-02T20:47:58+00:00 f52375e9fcb897c1b5c1741b0531debd617a4a67 commit 72b59d6ee8adaa51f70377db0a1917ed489bead8 upstream. If a backend IO takes a really long then an initiator might abort a command, and then when it gives up on the abort, send a LUN reset too, all before we process any of the original command or the abort. (The abort will wait for the backend IO to complete too) When the backend IO final completes (or fails), the abort handling will proceed and queue up a "return aborted status" operation. Then, while that's still pending, the LUN reset might find the original command still on the LUN's list of commands and try to return aborted status again, which leads to a use-after free when the first se_tfo->queue_status call frees the command and then the second se_tfo->queue_status call runs. Fix this by removing a command from the LUN state_list when we first are about to queue aborted status; we shouldn't do anything LUN-related after we've started returning status, so this seems like the correct thing to do. Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 72b59d6ee8adaa51f70377db0a1917ed489bead8 upstream.

If a backend IO takes a really long then an initiator might abort a
command, and then when it gives up on the abort, send a LUN reset too,
all before we process any of the original command or the abort.  (The
abort will wait for the backend IO to complete too)

When the backend IO final completes (or fails), the abort handling
will proceed and queue up a "return aborted status" operation.  Then,
while that's still pending, the LUN reset might find the original
command still on the LUN's list of commands and try to return aborted
status again, which leads to a use-after free when the first
se_tfo->queue_status call frees the command and then the second
se_tfo->queue_status call runs.

Fix this by removing a command from the LUN state_list when we first
are about to queue aborted status; we shouldn't do anything
LUN-related after we've started returning status, so this seems like
the correct thing to do.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
target: Fix missing CMD_T_ACTIVE bit regression for pending WRITEs 2013-01-21T19:44:33+00:00 Roland Dreier roland@purestorage.com 2013-01-02T20:47:57+00:00 6a153ea0afa8f709961203f2d3e56260df3d257b commit e627c615553a356f6f70215ebb3933c6e057553e upstream. This patch fixes a regression bug introduced during v3.6.x code with the following commit to drop transport_add_cmd_to_queue(), which originally re-set CMD_T_ACTIVE during pending WRITE I/O submission: commit af8772926f019b7bddd7477b8de5f3b0f12bad21 Author: Christoph Hellwig <hch@infradead.org> Date: Sun Jul 8 15:58:49 2012 -0400 target: replace the processing thread with a TMR work queue The following sequence happens for write commands (or any other commands with a data out phase): - The transport calls target_submit_cmd(), which sets CMD_T_ACTIVE in cmd->transport_state and sets cmd->t_state to TRANSPORT_NEW_CMD. - Things go on transport_generic_new_cmd(), which notices that the command needs to transfer data, so it sets cmd->t_state to TRANSPORT_WRITE_PENDING and calls transport_cmd_check_stop(). - transport_cmd_check_stop() clears CMD_T_ACTIVE in cmd->transport_state and returns in the normal case. - Then we continue on to call ->se_tfo->write_pending(). - The data comes back from the initiator, and the transport calls target_execute_cmd(), which sets cmd->t_state to TRANSPORT_PROCESSING and calls into the backend to actually write the data. At this point, the backend might take a long time to complete the command, since it has to do real IO. If an abort request comes in for this command at this point, it will not wait for the command to finish since CMD_T_ACTIVE is not set. Then when the command does finally finish, we blow up with use-after-free. Avoid this by setting CMD_T_ACTIVE in target_execute_cmd() so that transport_wait_for_tasks() waits for the command to finish executing. This matches the behavior from before commit 1389533ef944 ("target: remove transport_generic_handle_data"), when data was signaled via transport_generic_handle_data(), which set CMD_T_ACTIVE because it called transport_add_cmd_to_queue(). Signed-off-by: Roland Dreier <roland@purestorage.com> Reported-by: Martin Svec <martin.svec@zoner.cz> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e627c615553a356f6f70215ebb3933c6e057553e upstream.

This patch fixes a regression bug introduced during v3.6.x code with
the following commit to drop transport_add_cmd_to_queue(), which
originally re-set CMD_T_ACTIVE during pending WRITE I/O submission:

commit af8772926f019b7bddd7477b8de5f3b0f12bad21
Author: Christoph Hellwig <hch@infradead.org>
Date:   Sun Jul 8 15:58:49 2012 -0400

    target: replace the processing thread with a TMR work queue

The following sequence happens for write commands (or any other
commands with a data out phase):

 - The transport calls target_submit_cmd(), which sets CMD_T_ACTIVE in
   cmd->transport_state and sets cmd->t_state to TRANSPORT_NEW_CMD.
 - Things go on transport_generic_new_cmd(), which notices that the
   command needs to transfer data, so it sets cmd->t_state to
   TRANSPORT_WRITE_PENDING and calls transport_cmd_check_stop().
 - transport_cmd_check_stop() clears CMD_T_ACTIVE in cmd->transport_state
   and returns in the normal case.
 - Then we continue on to call ->se_tfo->write_pending().
 - The data comes back from the initiator, and the transport calls
   target_execute_cmd(), which sets cmd->t_state to TRANSPORT_PROCESSING
   and calls into the backend to actually write the data.

At this point, the backend might take a long time to complete the
command, since it has to do real IO.  If an abort request comes in for
this command at this point, it will not wait for the command to finish
since CMD_T_ACTIVE is not set.  Then when the command does finally
finish, we blow up with use-after-free.

Avoid this by setting CMD_T_ACTIVE in target_execute_cmd() so that
transport_wait_for_tasks() waits for the command to finish executing.
This matches the behavior from before commit 1389533ef944 ("target:
remove transport_generic_handle_data"), when data was signaled via
transport_generic_handle_data(), which set CMD_T_ACTIVE because it
called transport_add_cmd_to_queue().

Signed-off-by: Roland Dreier <roland@purestorage.com>
Reported-by: Martin Svec <martin.svec@zoner.cz>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tcm_fc: Do not report target role when target is not defined 2013-01-21T19:44:33+00:00 Mark Rustad mark.d.rustad@intel.com 2012-12-21T18:58:19+00:00 da863dd651cc228258165d80b494c9756c73b75f commit edec8dfefa1f372b2dd8197da555352e76a10c03 upstream. Clear the target role when no target is provided for the node performing a PRLI. Signed-off-by: Mark Rustad <mark.d.rustad@intel.com> Reviewed-by: Bhanu Prakash Gollapudi <bprakash@broadcom.com> Acked by Robert Love <robert.w.love@intel.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit edec8dfefa1f372b2dd8197da555352e76a10c03 upstream.

Clear the target role when no target is provided for
the node performing a PRLI.

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Reviewed-by: Bhanu Prakash Gollapudi <bprakash@broadcom.com>
Acked by Robert Love <robert.w.love@intel.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tcm_fc: Do not indicate retry capability to initiators 2013-01-21T19:44:33+00:00 Mark Rustad mark.d.rustad@intel.com 2012-12-21T18:58:14+00:00 cdaae60625299491d2b30d39a44592c3f19c4e56 commit f2eeba214bcd0215b7f558cab6420e5fd153042b upstream. When generating a PRLI response to an initiator, clear the FCP_SPPF_RETRY bit in the response. Signed-off-by: Mark Rustad <mark.d.rustad@intel.com> Reviewed-by: Bhanu Prakash Gollapudi <bprakash@broadcom.com> Acked by Robert Love <robert.w.love@intel.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit f2eeba214bcd0215b7f558cab6420e5fd153042b upstream.

When generating a PRLI response to an initiator, clear the
FCP_SPPF_RETRY bit in the response.

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Reviewed-by: Bhanu Prakash Gollapudi <bprakash@broadcom.com>
Acked by Robert Love <robert.w.love@intel.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
target: use correct sense code for LUN communication failure 2013-01-21T19:44:32+00:00 Hannes Reinecke hare@suse.de 2012-12-17T08:53:32+00:00 e7ee9ce24c682dbec3a725def2f79c49b08ab261 commit 18a9df42d53fabfa43b78be1104838cc8b9762e1 upstream. The ASC/ASCQ code for 'Logical Unit Communication failure' is 0x08/0x00; 0x80/0x00 is vendor specific. Signed-off-by: Hannes Reinecke <hare@suse.de> Cc: Nicholas Bellinger <nab@risingtidesystems.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 18a9df42d53fabfa43b78be1104838cc8b9762e1 upstream.

The ASC/ASCQ code for 'Logical Unit Communication failure' is
0x08/0x00; 0x80/0x00 is vendor specific.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Cc: Nicholas Bellinger <nab@risingtidesystems.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
iscsi-target: Fix CmdSN comparison (use cmd->cmd_sn instead of cmd->stat_sn) 2013-01-17T16:46:24+00:00 Roland Dreier roland@purestorage.com 2013-01-07T19:45:16+00:00 044882a62f34cd6460196c13773bd210be39d717 commit 64fe4f4f181cc2fe97d4176bf6ee6e3725ae33ec upstream. Commit 64c13330a389 ("iscsi-target: Fix bug in handling of ExpStatSN ACK during u32 wrap-around") introduced a bug where we compare the wrong SN against our ExpCmdSN. Reported-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Cc: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 64fe4f4f181cc2fe97d4176bf6ee6e3725ae33ec upstream.

Commit 64c13330a389 ("iscsi-target: Fix bug in handling of ExpStatSN
ACK during u32 wrap-around") introduced a bug where we compare the
wrong SN against our ExpCmdSN.

Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sbp-target: fix error path in sbp_make_tpg() 2013-01-17T16:45:58+00:00 Chris Boot bootc@bootc.net 2012-12-11T21:58:48+00:00 ffd939ebf39c50a5f4e192870125bd6e2875f05d commit e1fe2060d7e8f58a69374135e32e90f0bb79a7fd upstream. If the TPG memory is allocated successfully, but we fail further along in the function, a dangling pointer to freed memory is left in the TPort structure. This is mostly harmless, but does prevent re-trying the operation without first removing the TPort altogether. Reported-by: Chen Gang <gang.chen@asianux.com> Signed-off-by: Chris Boot <bootc@bootc.net> Cc: Andy Grover <agrover@redhat.com> Cc: Nicholas A. Bellinger <nab@linux-iscsi.org> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e1fe2060d7e8f58a69374135e32e90f0bb79a7fd upstream.

If the TPG memory is allocated successfully, but we fail further along
in the function, a dangling pointer to freed memory is left in the TPort
structure. This is mostly harmless, but does prevent re-trying the
operation without first removing the TPort altogether.

Reported-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Chris Boot <bootc@bootc.net>
Cc: Andy Grover <agrover@redhat.com>
Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
target/tcm_fc: fix the lockdep warning due to inconsistent lock state 2013-01-17T16:45:58+00:00 Yi Zou yi.zou@intel.com 2012-12-11T01:04:00+00:00 3930216ba48431031d13f7ef757363852040a058 commit 9f4ad44b264f8bb61ffdd607148215566568430d upstream. The lockdep warning below is in theory correct but it will be in really weird rare situation that ends up that deadlock since the tcm fc session is hashed based the rport id. Nonetheless, the complaining below is about rcu callback that does the transport_deregister_session() is happening in softirq, where transport_register_session() that happens earlier is not. This triggers the lockdep warning below. So, just fix this to make lockdep happy by disabling the soft irq before calling transport_register_session() in ft_prli. BTW, this was found in FCoE VN2VN over two VMs, couple of create and destroy would get this triggered. v1: was enforcing register to be in softirq context which was not righ. See, http://www.spinics.net/lists/target-devel/msg03614.html v2: following comments from Roland&Nick (thanks), it seems we don't have to do transport_deregister_session() in rcu callback, so move it into ft_sess_free() but still do kfree() of the corresponding ft_sess struct in rcu callback to make sure the ft_sess is not freed till the rcu callback. ... [ 1328.370592] scsi2 : FCoE Driver [ 1328.383429] fcoe: No FDMI support. [ 1328.384509] host2: libfc: Link up on port (000000) [ 1328.934229] host2: Assigned Port ID 00a292 [ 1357.232132] host2: rport 00a393: Remove port [ 1357.232568] host2: rport 00a393: Port sending LOGO from Ready state [ 1357.233692] host2: rport 00a393: Delete port [ 1357.234472] host2: rport 00a393: work event 3 [ 1357.234969] host2: rport 00a393: callback ev 3 [ 1357.235979] host2: rport 00a393: Received a LOGO response closed [ 1357.236706] host2: rport 00a393: work delete [ 1357.237481] [ 1357.237631] ================================= [ 1357.238064] [ INFO: inconsistent lock state ] [ 1357.238450] 3.7.0-rc7-yikvm+ #3 Tainted: G O [ 1357.238450] --------------------------------- [ 1357.238450] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. [ 1357.238450] ksoftirqd/0/3 [HC0[0]:SC1[1]:HE0:SE0] takes: [ 1357.238450] (&(&se_tpg->session_lock)->rlock){+.?...}, at: [<ffffffffa01eacd4>] transport_deregister_session+0x41/0x148 [target_core_mod] [ 1357.238450] {SOFTIRQ-ON-W} state was registered at: [ 1357.238450] [<ffffffff810834f5>] mark_held_locks+0x6d/0x95 [ 1357.238450] [<ffffffff8108364a>] trace_hardirqs_on_caller+0x12d/0x197 [ 1357.238450] [<ffffffff810836c1>] trace_hardirqs_on+0xd/0xf [ 1357.238450] [<ffffffff8149caba>] _raw_spin_unlock_irq+0x2d/0x45 [ 1357.238450] [<ffffffffa01e8d10>] __transport_register_session+0xb8/0x122 [target_core_mod] [ 1357.238450] [<ffffffffa01e8dbe>] transport_register_session+0x44/0x5a [target_core_mod] [ 1357.238450] [<ffffffffa018e32c>] ft_prli+0x1e3/0x275 [tcm_fc] [ 1357.238450] [<ffffffffa0160e8d>] fc_rport_recv_req+0x95e/0xdc5 [libfc] [ 1357.238450] [<ffffffffa015be88>] fc_lport_recv_els_req+0xc4/0xd5 [libfc] [ 1357.238450] [<ffffffffa015c778>] fc_lport_recv_req+0x12f/0x18f [libfc] [ 1357.238450] [<ffffffffa015a6d7>] fc_exch_recv+0x8ba/0x981 [libfc] [ 1357.238450] [<ffffffffa0176d7a>] fcoe_percpu_receive_thread+0x47a/0x4e2 [fcoe] [ 1357.238450] [<ffffffff810549f1>] kthread+0xb1/0xb9 [ 1357.238450] [<ffffffff814a40ec>] ret_from_fork+0x7c/0xb0 [ 1357.238450] irq event stamp: 275411 [ 1357.238450] hardirqs last enabled at (275410): [<ffffffff810bb6a0>] rcu_process_callbacks+0x229/0x42a [ 1357.238450] hardirqs last disabled at (275411): [<ffffffff8149c2f7>] _raw_spin_lock_irqsave+0x22/0x8e [ 1357.238450] softirqs last enabled at (275394): [<ffffffff8103d669>] __do_softirq+0x246/0x26f [ 1357.238450] softirqs last disabled at (275399): [<ffffffff8103d6bb>] run_ksoftirqd+0x29/0x62 [ 1357.238450] [ 1357.238450] other info that might help us debug this: [ 1357.238450] Possible unsafe locking scenario: [ 1357.238450] [ 1357.238450] CPU0 [ 1357.238450] ---- [ 1357.238450] lock(&(&se_tpg->session_lock)->rlock); [ 1357.238450] <Interrupt> [ 1357.238450] lock(&(&se_tpg->session_lock)->rlock); [ 1357.238450] [ 1357.238450] *** DEADLOCK *** [ 1357.238450] [ 1357.238450] no locks held by ksoftirqd/0/3. [ 1357.238450] [ 1357.238450] stack backtrace: [ 1357.238450] Pid: 3, comm: ksoftirqd/0 Tainted: G O 3.7.0-rc7-yikvm+ #3 [ 1357.238450] Call Trace: [ 1357.238450] [<ffffffff8149399a>] print_usage_bug+0x1f5/0x206 [ 1357.238450] [<ffffffff8100da59>] ? save_stack_trace+0x2c/0x49 [ 1357.238450] [<ffffffff81082aae>] ? print_irq_inversion_bug.part.14+0x1ae/0x1ae [ 1357.238450] [<ffffffff81083336>] mark_lock+0x106/0x258 [ 1357.238450] [<ffffffff81084e34>] __lock_acquire+0x2e7/0xe53 [ 1357.238450] [<ffffffff8102903d>] ? pvclock_clocksource_read+0x48/0xb4 [ 1357.238450] [<ffffffff810ba6a3>] ? rcu_process_gp_end+0xc0/0xc9 [ 1357.238450] [<ffffffffa01eacd4>] ? transport_deregister_session+0x41/0x148 [target_core_mod] [ 1357.238450] [<ffffffff81085ef1>] lock_acquire+0x119/0x143 [ 1357.238450] [<ffffffffa01eacd4>] ? transport_deregister_session+0x41/0x148 [target_core_mod] [ 1357.238450] [<ffffffff8149c329>] _raw_spin_lock_irqsave+0x54/0x8e [ 1357.238450] [<ffffffffa01eacd4>] ? transport_deregister_session+0x41/0x148 [target_core_mod] [ 1357.238450] [<ffffffffa01eacd4>] transport_deregister_session+0x41/0x148 [target_core_mod] [ 1357.238450] [<ffffffff810bb6a0>] ? rcu_process_callbacks+0x229/0x42a [ 1357.238450] [<ffffffffa018ddc5>] ft_sess_rcu_free+0x17/0x24 [tcm_fc] [ 1357.238450] [<ffffffffa018ddae>] ? ft_sess_free+0x1b/0x1b [tcm_fc] [ 1357.238450] [<ffffffff810bb6d7>] rcu_process_callbacks+0x260/0x42a [ 1357.238450] [<ffffffff8103d55d>] __do_softirq+0x13a/0x26f [ 1357.238450] [<ffffffff8149b34e>] ? __schedule+0x65f/0x68e [ 1357.238450] [<ffffffff8103d6bb>] run_ksoftirqd+0x29/0x62 [ 1357.238450] [<ffffffff8105c83c>] smpboot_thread_fn+0x1a5/0x1aa [ 1357.238450] [<ffffffff8105c697>] ? smpboot_unregister_percpu_thread+0x47/0x47 [ 1357.238450] [<ffffffff810549f1>] kthread+0xb1/0xb9 [ 1357.238450] [<ffffffff8149b49d>] ? wait_for_common+0xbb/0x10a [ 1357.238450] [<ffffffff81054940>] ? __init_kthread_worker+0x59/0x59 [ 1357.238450] [<ffffffff814a40ec>] ret_from_fork+0x7c/0xb0 [ 1357.238450] [<ffffffff81054940>] ? __init_kthread_worker+0x59/0x59 [ 1417.440099] rport-2:0-0: blocked FC remote port time out: removing rport Signed-off-by: Yi Zou <yi.zou@intel.com> Cc: Open-FCoE <devel@open-fcoe.org> Cc: Nicholas A. Bellinger <nab@risingtidesystems.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 9f4ad44b264f8bb61ffdd607148215566568430d upstream.

The lockdep warning below is in theory correct but it will be in really weird
rare situation that ends up that deadlock since the tcm fc session is hashed
based the rport id. Nonetheless, the complaining below is about rcu callback
that does the transport_deregister_session() is happening in softirq, where
transport_register_session() that happens earlier is not. This triggers the
lockdep warning below. So, just fix this to make lockdep happy by disabling
the soft irq before calling transport_register_session() in ft_prli.

BTW, this was found in FCoE VN2VN over two VMs, couple of create and destroy
would get this triggered.

v1: was enforcing register to be in softirq context which was not righ. See,
http://www.spinics.net/lists/target-devel/msg03614.html

v2: following comments from Roland&Nick (thanks), it seems we don't have to
do transport_deregister_session() in rcu callback, so move it into ft_sess_free()
but still do kfree() of the corresponding ft_sess struct in rcu callback to
make sure the ft_sess is not freed till the rcu callback.

...
[ 1328.370592] scsi2 : FCoE Driver
[ 1328.383429] fcoe: No FDMI support.
[ 1328.384509] host2: libfc: Link up on port (000000)
[ 1328.934229] host2: Assigned Port ID 00a292
[ 1357.232132] host2: rport 00a393: Remove port
[ 1357.232568] host2: rport 00a393: Port sending LOGO from Ready state
[ 1357.233692] host2: rport 00a393: Delete port
[ 1357.234472] host2: rport 00a393: work event 3
[ 1357.234969] host2: rport 00a393: callback ev 3
[ 1357.235979] host2: rport 00a393: Received a LOGO response closed
[ 1357.236706] host2: rport 00a393: work delete
[ 1357.237481]
[ 1357.237631] =================================
[ 1357.238064] [ INFO: inconsistent lock state ]
[ 1357.238450] 3.7.0-rc7-yikvm+ #3 Tainted: G           O
[ 1357.238450] ---------------------------------
[ 1357.238450] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
[ 1357.238450] ksoftirqd/0/3 [HC0[0]:SC1[1]:HE0:SE0] takes:
[ 1357.238450]  (&(&se_tpg->session_lock)->rlock){+.?...}, at: [<ffffffffa01eacd4>] transport_deregister_session+0x41/0x148 [target_core_mod]
[ 1357.238450] {SOFTIRQ-ON-W} state was registered at:
[ 1357.238450]   [<ffffffff810834f5>] mark_held_locks+0x6d/0x95
[ 1357.238450]   [<ffffffff8108364a>] trace_hardirqs_on_caller+0x12d/0x197
[ 1357.238450]   [<ffffffff810836c1>] trace_hardirqs_on+0xd/0xf
[ 1357.238450]   [<ffffffff8149caba>] _raw_spin_unlock_irq+0x2d/0x45
[ 1357.238450]   [<ffffffffa01e8d10>] __transport_register_session+0xb8/0x122 [target_core_mod]
[ 1357.238450]   [<ffffffffa01e8dbe>] transport_register_session+0x44/0x5a [target_core_mod]
[ 1357.238450]   [<ffffffffa018e32c>] ft_prli+0x1e3/0x275 [tcm_fc]
[ 1357.238450]   [<ffffffffa0160e8d>] fc_rport_recv_req+0x95e/0xdc5 [libfc]
[ 1357.238450]   [<ffffffffa015be88>] fc_lport_recv_els_req+0xc4/0xd5 [libfc]
[ 1357.238450]   [<ffffffffa015c778>] fc_lport_recv_req+0x12f/0x18f [libfc]
[ 1357.238450]   [<ffffffffa015a6d7>] fc_exch_recv+0x8ba/0x981 [libfc]
[ 1357.238450]   [<ffffffffa0176d7a>] fcoe_percpu_receive_thread+0x47a/0x4e2 [fcoe]
[ 1357.238450]   [<ffffffff810549f1>] kthread+0xb1/0xb9
[ 1357.238450]   [<ffffffff814a40ec>] ret_from_fork+0x7c/0xb0
[ 1357.238450] irq event stamp: 275411
[ 1357.238450] hardirqs last  enabled at (275410): [<ffffffff810bb6a0>] rcu_process_callbacks+0x229/0x42a
[ 1357.238450] hardirqs last disabled at (275411): [<ffffffff8149c2f7>] _raw_spin_lock_irqsave+0x22/0x8e
[ 1357.238450] softirqs last  enabled at (275394): [<ffffffff8103d669>] __do_softirq+0x246/0x26f
[ 1357.238450] softirqs last disabled at (275399): [<ffffffff8103d6bb>] run_ksoftirqd+0x29/0x62
[ 1357.238450]
[ 1357.238450] other info that might help us debug this:
[ 1357.238450]  Possible unsafe locking scenario:
[ 1357.238450]
[ 1357.238450]        CPU0
[ 1357.238450]        ----
[ 1357.238450]   lock(&(&se_tpg->session_lock)->rlock);
[ 1357.238450]   <Interrupt>
[ 1357.238450]     lock(&(&se_tpg->session_lock)->rlock);
[ 1357.238450]
[ 1357.238450]  *** DEADLOCK ***
[ 1357.238450]
[ 1357.238450] no locks held by ksoftirqd/0/3.
[ 1357.238450]
[ 1357.238450] stack backtrace:
[ 1357.238450] Pid: 3, comm: ksoftirqd/0 Tainted: G           O 3.7.0-rc7-yikvm+ #3
[ 1357.238450] Call Trace:
[ 1357.238450]  [<ffffffff8149399a>] print_usage_bug+0x1f5/0x206
[ 1357.238450]  [<ffffffff8100da59>] ? save_stack_trace+0x2c/0x49
[ 1357.238450]  [<ffffffff81082aae>] ? print_irq_inversion_bug.part.14+0x1ae/0x1ae
[ 1357.238450]  [<ffffffff81083336>] mark_lock+0x106/0x258
[ 1357.238450]  [<ffffffff81084e34>] __lock_acquire+0x2e7/0xe53
[ 1357.238450]  [<ffffffff8102903d>] ? pvclock_clocksource_read+0x48/0xb4
[ 1357.238450]  [<ffffffff810ba6a3>] ? rcu_process_gp_end+0xc0/0xc9
[ 1357.238450]  [<ffffffffa01eacd4>] ? transport_deregister_session+0x41/0x148 [target_core_mod]
[ 1357.238450]  [<ffffffff81085ef1>] lock_acquire+0x119/0x143
[ 1357.238450]  [<ffffffffa01eacd4>] ? transport_deregister_session+0x41/0x148 [target_core_mod]
[ 1357.238450]  [<ffffffff8149c329>] _raw_spin_lock_irqsave+0x54/0x8e
[ 1357.238450]  [<ffffffffa01eacd4>] ? transport_deregister_session+0x41/0x148 [target_core_mod]
[ 1357.238450]  [<ffffffffa01eacd4>] transport_deregister_session+0x41/0x148 [target_core_mod]
[ 1357.238450]  [<ffffffff810bb6a0>] ? rcu_process_callbacks+0x229/0x42a
[ 1357.238450]  [<ffffffffa018ddc5>] ft_sess_rcu_free+0x17/0x24 [tcm_fc]
[ 1357.238450]  [<ffffffffa018ddae>] ? ft_sess_free+0x1b/0x1b [tcm_fc]
[ 1357.238450]  [<ffffffff810bb6d7>] rcu_process_callbacks+0x260/0x42a
[ 1357.238450]  [<ffffffff8103d55d>] __do_softirq+0x13a/0x26f
[ 1357.238450]  [<ffffffff8149b34e>] ? __schedule+0x65f/0x68e
[ 1357.238450]  [<ffffffff8103d6bb>] run_ksoftirqd+0x29/0x62
[ 1357.238450]  [<ffffffff8105c83c>] smpboot_thread_fn+0x1a5/0x1aa
[ 1357.238450]  [<ffffffff8105c697>] ? smpboot_unregister_percpu_thread+0x47/0x47
[ 1357.238450]  [<ffffffff810549f1>] kthread+0xb1/0xb9
[ 1357.238450]  [<ffffffff8149b49d>] ? wait_for_common+0xbb/0x10a
[ 1357.238450]  [<ffffffff81054940>] ? __init_kthread_worker+0x59/0x59
[ 1357.238450]  [<ffffffff814a40ec>] ret_from_fork+0x7c/0xb0
[ 1357.238450]  [<ffffffff81054940>] ? __init_kthread_worker+0x59/0x59
[ 1417.440099]  rport-2:0-0: blocked FC remote port time out: removing rport

Signed-off-by: Yi Zou <yi.zou@intel.com>
Cc: Open-FCoE <devel@open-fcoe.org>
Cc: Nicholas A. Bellinger <nab@risingtidesystems.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>