Bart Van Assche 5b6a40e532 qla2x00t-32gbit: Fix unsafe locking
Avoid that lockdep reports the following:

WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected
kworker/2:1/62 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
0000000009e679b3 (&(&k->k_lock)->rlock){+.+.}, at: klist_next+0x43/0x1d0

and this task is already holding:
00000000a033b71c (&(&ha->tgt.sess_lock)->rlock){-...}, at: qla24xx_delete_sess_fn+0x55/0xf0 [qla2xxx_scst]
which would create a new lock dependency:
 (&(&ha->tgt.sess_lock)->rlock){-...} -> (&(&k->k_lock)->rlock){+.+.}

but this new dependency connects a HARDIRQ-irq-safe lock:
 (&(&ha->tgt.sess_lock)->rlock){-...}

... which became HARDIRQ-irq-safe at:
  lock_acquire+0xe3/0x200
  _raw_spin_lock_irqsave+0x3d/0x60
  qla24xx_report_id_acquisition+0xa69/0xe30 [qla2xxx_scst]
  qla24xx_process_response_queue+0x69e/0x1270 [qla2xxx_scst]
  qla24xx_msix_rsp_q+0x79/0xf0 [qla2xxx_scst]
  __handle_irq_event_percpu+0x79/0x3c0
  handle_irq_event_percpu+0x70/0xf0
  handle_irq_event+0x5a/0x8b
  handle_edge_irq+0x12c/0x310
  handle_irq+0x192/0x20a
  do_IRQ+0x73/0x160
  ret_from_intr+0x0/0x1d
  default_idle+0x23/0x1f0
  arch_cpu_idle+0x15/0x20
  default_idle_call+0x35/0x40
  do_idle+0x2bb/0x2e0
  cpu_startup_entry+0x1d/0x20
  start_secondary+0x2a8/0x320
  secondary_startup_64+0xa4/0xb0

to a HARDIRQ-irq-unsafe lock:
 (&(&k->k_lock)->rlock){+.+.}

... which became HARDIRQ-irq-unsafe at:
...
  lock_acquire+0xe3/0x200
  _raw_spin_lock+0x32/0x50
  klist_add_tail+0x33/0xb0
  device_add+0x7e1/0xb50
  device_create_groups_vargs+0x11c/0x150
  device_create_with_groups+0x89/0xb0
  vtconsole_class_init+0xb2/0x124
  do_one_initcall+0xc5/0x3ce
  kernel_init_freeable+0x295/0x32e
  kernel_init+0x11/0x11b
  ret_from_fork+0x3a/0x50

other info that might help us debug this:

 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&(&k->k_lock)->rlock);
                               local_irq_disable();
                               lock(&(&ha->tgt.sess_lock)->rlock);
                               lock(&(&k->k_lock)->rlock);
  <Interrupt>
    lock(&(&ha->tgt.sess_lock)->rlock);

 *** DEADLOCK ***

3 locks held by kworker/2:1/62:
 #0: 00000000a4319c16 ((wq_completion)"qla2xxx_wq"){+.+.}, at: process_one_work+0x437/0xa80
 #1: 00000000ffa34c42 ((work_completion)(&sess->del_work)){+.+.}, at: process_one_work+0x437/0xa80
 #2: 00000000a033b71c (&(&ha->tgt.sess_lock)->rlock){-...}, at: qla24xx_delete_sess_fn+0x55/0xf0 [qla2xxx_scst]

the dependencies between HARDIRQ-irq-safe lock and the holding lock:
-> (&(&ha->tgt.sess_lock)->rlock){-...} ops: 8 {
   IN-HARDIRQ-W at:
                    lock_acquire+0xe3/0x200
                    _raw_spin_lock_irqsave+0x3d/0x60
                    qla24xx_report_id_acquisition+0xa69/0xe30 [qla2xxx_scst]
                    qla24xx_process_response_queue+0x69e/0x1270 [qla2xxx_scst]
                    qla24xx_msix_rsp_q+0x79/0xf0 [qla2xxx_scst]
                    __handle_irq_event_percpu+0x79/0x3c0
                    handle_irq_event_percpu+0x70/0xf0
                    handle_irq_event+0x5a/0x8b
                    handle_edge_irq+0x12c/0x310
                    handle_irq+0x192/0x20a
                    do_IRQ+0x73/0x160
                    ret_from_intr+0x0/0x1d
                    default_idle+0x23/0x1f0
                    arch_cpu_idle+0x15/0x20
                    default_idle_call+0x35/0x40
                    do_idle+0x2bb/0x2e0
                    cpu_startup_entry+0x1d/0x20
                    start_secondary+0x2a8/0x320
                    secondary_startup_64+0xa4/0xb0
   INITIAL USE at:
                   lock_acquire+0xe3/0x200
                   _raw_spin_lock_irqsave+0x3d/0x60
                   qla24xx_report_id_acquisition+0xa69/0xe30 [qla2xxx_scst]
                   qla24xx_process_response_queue+0x69e/0x1270 [qla2xxx_scst]
                   qla24xx_msix_rsp_q+0x79/0xf0 [qla2xxx_scst]
                   __handle_irq_event_percpu+0x79/0x3c0
                   handle_irq_event_percpu+0x70/0xf0
                   handle_irq_event+0x5a/0x8b
                   handle_edge_irq+0x12c/0x310
                   handle_irq+0x192/0x20a
                   do_IRQ+0x73/0x160
                   ret_from_intr+0x0/0x1d
                   default_idle+0x23/0x1f0
                   arch_cpu_idle+0x15/0x20
                   default_idle_call+0x35/0x40
                   do_idle+0x2bb/0x2e0
                   cpu_startup_entry+0x1d/0x20
                   start_secondary+0x2a8/0x320
                   secondary_startup_64+0xa4/0xb0
 }
 ... key      at: [<ffffffffa0c0d080>] __key.85462+0x0/0xfffffffffff7df80 [qla2xxx_scst]
 ... acquired at:
   lock_acquire+0xe3/0x200
   _raw_spin_lock_irqsave+0x3d/0x60
   klist_next+0x43/0x1d0
   device_for_each_child+0x96/0x110
   scsi_target_block+0x3c/0x40 [scsi_mod]
   fc_remote_port_delete+0xe7/0x1c0 [scsi_transport_fc]
   qla2x00_mark_device_lost+0xa0b/0xa30 [qla2xxx_scst]
   qlt_unreg_sess+0x1c6/0x380 [qla2xxx_scst]
   qla24xx_delete_sess_fn+0xe6/0xf0 [qla2xxx_scst]
   process_one_work+0x511/0xa80
   worker_thread+0x67/0x5b0
   kthread+0x1d2/0x1f0
   ret_from_fork+0x3a/0x50

the dependencies between the lock to be acquired
 and HARDIRQ-irq-unsafe lock:
-> (&(&k->k_lock)->rlock){+.+.} ops: 13831 {
   HARDIRQ-ON-W at:
                    lock_acquire+0xe3/0x200
                    _raw_spin_lock+0x32/0x50
                    klist_add_tail+0x33/0xb0
                    device_add+0x7e1/0xb50
                    device_create_groups_vargs+0x11c/0x150
                    device_create_with_groups+0x89/0xb0
                    vtconsole_class_init+0xb2/0x124
                    do_one_initcall+0xc5/0x3ce
                    kernel_init_freeable+0x295/0x32e
                    kernel_init+0x11/0x11b
                    ret_from_fork+0x3a/0x50
   SOFTIRQ-ON-W at:
                    lock_acquire+0xe3/0x200
                    _raw_spin_lock+0x32/0x50
                    klist_add_tail+0x33/0xb0
                    device_add+0x7e1/0xb50
                    device_create_groups_vargs+0x11c/0x150
                    device_create_with_groups+0x89/0xb0
                    vtconsole_class_init+0xb2/0x124
                    do_one_initcall+0xc5/0x3ce
                    kernel_init_freeable+0x295/0x32e
                    kernel_init+0x11/0x11b
                    ret_from_fork+0x3a/0x50
   INITIAL USE at:
                   lock_acquire+0xe3/0x200
                   _raw_spin_lock+0x32/0x50
                   klist_add_tail+0x33/0xb0
                   device_add+0x7e1/0xb50
                   device_create_groups_vargs+0x11c/0x150
                   device_create_with_groups+0x89/0xb0
                   vtconsole_class_init+0xb2/0x124
                   do_one_initcall+0xc5/0x3ce
                   kernel_init_freeable+0x295/0x32e
                   kernel_init+0x11/0x11b
                   ret_from_fork+0x3a/0x50
 }
 ... key      at: [<ffffffff83ed8780>] __key.15491+0x0/0x40
 ... acquired at:
   lock_acquire+0xe3/0x200
   _raw_spin_lock_irqsave+0x3d/0x60
   klist_next+0x43/0x1d0
   device_for_each_child+0x96/0x110
   scsi_target_block+0x3c/0x40 [scsi_mod]
   fc_remote_port_delete+0xe7/0x1c0 [scsi_transport_fc]
   qla2x00_mark_device_lost+0xa0b/0xa30 [qla2xxx_scst]
   qlt_unreg_sess+0x1c6/0x380 [qla2xxx_scst]
   qla24xx_delete_sess_fn+0xe6/0xf0 [qla2xxx_scst]
   process_one_work+0x511/0xa80
   worker_thread+0x67/0x5b0
   kthread+0x1d2/0x1f0
   ret_from_fork+0x3a/0x50

stack backtrace:
CPU: 2 PID: 62 Comm: kworker/2:1 Tainted: G           O      5.0.7-dbg+ #8
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Workqueue: qla2xxx_wq qla24xx_delete_sess_fn [qla2xxx_scst]
Call Trace:
 dump_stack+0x86/0xca
 check_usage.cold.52+0x473/0x563
 __lock_acquire+0x11c0/0x23e0
 lock_acquire+0xe3/0x200
 _raw_spin_lock_irqsave+0x3d/0x60
 klist_next+0x43/0x1d0
 device_for_each_child+0x96/0x110
 scsi_target_block+0x3c/0x40 [scsi_mod]
 fc_remote_port_delete+0xe7/0x1c0 [scsi_transport_fc]
 qla2x00_mark_device_lost+0xa0b/0xa30 [qla2xxx_scst]
 qlt_unreg_sess+0x1c6/0x380 [qla2xxx_scst]
 qla24xx_delete_sess_fn+0xe6/0xf0 [qla2xxx_scst]
 process_one_work+0x511/0xa80
 worker_thread+0x67/0x5b0
 kthread+0x1d2/0x1f0
 ret_from_fork+0x3a/0x50



git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@8185 d57e44dd-8a1f-0410-8b47-8ef2f437770f
2019-04-13 22:48:25 +00:00
2019-02-12 03:07:54 +00:00
2018-12-31 19:03:14 +00:00
2018-12-31 19:03:14 +00:00
2018-12-31 18:27:35 +00:00

Overview
========

This is the SCST development repository. It contains not a single
project SCST as one can think, but a number of them, which are divided
as the following:

1. SCST core in scst/ subdirectory

2. Administration utility for SCST core scstadmin in scstadmin/

3. Target drivers in own subdirectories qla2x00t/, iscsi-scst/, etc.

4. User space programs in usr/ subdirectory, like fileio_tgt.

5. Some various docs in doc/ subdirectory.

Those subprojects are in most cases independent from each other,
although some of them depend from the SCST core. They put in the single
repository only to simplify their development, they are released
independently.

Thus, use "make all" only if you really need to build everything.
Otherwise build only what you need, like for iSCSI-SCST:

make scst scst_install iscsi iscsi_install

For more information about each subproject see their README files.


QLogic target driver
====================

QLogic target driver qla2x00t is the old driver, forked from qla2xxx
several years ago. It is very stable, well tested and actively used in
many production setups.

There is also new driver, maintained by QLogic, which, among other,
supports 32G FC, see http://scst.sourceforge.net/target_qla2x00t.html.
You can find the latest version of it in git://git.qlogic.com/scst-qla2xxx.git.

To integrate it into the SCST build tree you need to clone the QLogic
git tree in a subdirectory of this directory (SCST root tree) with name
qla2x00t_git (or create a symlink with this name pointing to any other
location in your system).

Now common and QLA specific root Makefile targets "magically" start
working with the new driver. Then follow instructions in the git's
README.

In presence of qla2x00t_git subdirectory you can still build the
qla2x00t using qla_old* root Makefile targets.

Vladislav Bolkhovitin <vst@vlnb.net>, http://scst.sourceforge.net
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