linux.git/drivers/scsi/libiscsi.c, branch v5.5 Linux kernel source tree scsi: iscsi: Fix a potential deadlock in the timeout handler 2019-12-10T00:19:28+00:00 Bart Van Assche bvanassche@acm.org 2019-12-09T17:34:57+00:00 5480e299b5ae57956af01d4839c9fc88a465eeab Some time ago the block layer was modified such that timeout handlers are called from thread context instead of interrupt context. Make it safe to run the iSCSI timeout handler in thread context. This patch fixes the following lockdep complaint: ================================ WARNING: inconsistent lock state 5.5.1-dbg+ #11 Not tainted -------------------------------- inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage. kworker/7:1H/206 [HC0[0]:SC0[0]:HE1:SE1] takes: ffff88802d9827e8 (&(&session->frwd_lock)->rlock){+.?.}, at: iscsi_eh_cmd_timed_out+0xa6/0x6d0 [libiscsi] {IN-SOFTIRQ-W} state was registered at: lock_acquire+0x106/0x240 _raw_spin_lock+0x38/0x50 iscsi_check_transport_timeouts+0x3e/0x210 [libiscsi] call_timer_fn+0x132/0x470 __run_timers.part.0+0x39f/0x5b0 run_timer_softirq+0x63/0xc0 __do_softirq+0x12d/0x5fd irq_exit+0xb3/0x110 smp_apic_timer_interrupt+0x131/0x3d0 apic_timer_interrupt+0xf/0x20 default_idle+0x31/0x230 arch_cpu_idle+0x13/0x20 default_idle_call+0x53/0x60 do_idle+0x38a/0x3f0 cpu_startup_entry+0x24/0x30 start_secondary+0x222/0x290 secondary_startup_64+0xa4/0xb0 irq event stamp: 1383705 hardirqs last enabled at (1383705): [<ffffffff81aace5c>] _raw_spin_unlock_irq+0x2c/0x50 hardirqs last disabled at (1383704): [<ffffffff81aacb98>] _raw_spin_lock_irq+0x18/0x50 softirqs last enabled at (1383690): [<ffffffffa0e2efea>] iscsi_queuecommand+0x76a/0xa20 [libiscsi] softirqs last disabled at (1383682): [<ffffffffa0e2e998>] iscsi_queuecommand+0x118/0xa20 [libiscsi] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(&session->frwd_lock)->rlock); <Interrupt> lock(&(&session->frwd_lock)->rlock); *** DEADLOCK *** 2 locks held by kworker/7:1H/206: #0: ffff8880d57bf928 ((wq_completion)kblockd){+.+.}, at: process_one_work+0x472/0xab0 #1: ffff88802b9c7de8 ((work_completion)(&q->timeout_work)){+.+.}, at: process_one_work+0x476/0xab0 stack backtrace: CPU: 7 PID: 206 Comm: kworker/7:1H Not tainted 5.5.1-dbg+ #11 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Workqueue: kblockd blk_mq_timeout_work Call Trace: dump_stack+0xa5/0xe6 print_usage_bug.cold+0x232/0x23b mark_lock+0x8dc/0xa70 __lock_acquire+0xcea/0x2af0 lock_acquire+0x106/0x240 _raw_spin_lock+0x38/0x50 iscsi_eh_cmd_timed_out+0xa6/0x6d0 [libiscsi] scsi_times_out+0xf4/0x440 [scsi_mod] scsi_timeout+0x1d/0x20 [scsi_mod] blk_mq_check_expired+0x365/0x3a0 bt_iter+0xd6/0xf0 blk_mq_queue_tag_busy_iter+0x3de/0x650 blk_mq_timeout_work+0x1af/0x380 process_one_work+0x56d/0xab0 worker_thread+0x7a/0x5d0 kthread+0x1bc/0x210 ret_from_fork+0x24/0x30 Fixes: 287922eb0b18 ("block: defer timeouts to a workqueue") Cc: Christoph Hellwig <hch@lst.de> Cc: Keith Busch <keith.busch@intel.com> Cc: Lee Duncan <lduncan@suse.com> Cc: Chris Leech <cleech@redhat.com> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20191209173457.187370-1-bvanassche@acm.org Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Lee Duncan <lduncan@suse.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> 
Some time ago the block layer was modified such that timeout handlers are
called from thread context instead of interrupt context. Make it safe to
run the iSCSI timeout handler in thread context. This patch fixes the
following lockdep complaint:

================================
WARNING: inconsistent lock state
5.5.1-dbg+ #11 Not tainted
--------------------------------
inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
kworker/7:1H/206 [HC0[0]:SC0[0]:HE1:SE1] takes:
ffff88802d9827e8 (&(&session->frwd_lock)->rlock){+.?.}, at: iscsi_eh_cmd_timed_out+0xa6/0x6d0 [libiscsi]
{IN-SOFTIRQ-W} state was registered at:
  lock_acquire+0x106/0x240
  _raw_spin_lock+0x38/0x50
  iscsi_check_transport_timeouts+0x3e/0x210 [libiscsi]
  call_timer_fn+0x132/0x470
  __run_timers.part.0+0x39f/0x5b0
  run_timer_softirq+0x63/0xc0
  __do_softirq+0x12d/0x5fd
  irq_exit+0xb3/0x110
  smp_apic_timer_interrupt+0x131/0x3d0
  apic_timer_interrupt+0xf/0x20
  default_idle+0x31/0x230
  arch_cpu_idle+0x13/0x20
  default_idle_call+0x53/0x60
  do_idle+0x38a/0x3f0
  cpu_startup_entry+0x24/0x30
  start_secondary+0x222/0x290
  secondary_startup_64+0xa4/0xb0
irq event stamp: 1383705
hardirqs last  enabled at (1383705): [<ffffffff81aace5c>] _raw_spin_unlock_irq+0x2c/0x50
hardirqs last disabled at (1383704): [<ffffffff81aacb98>] _raw_spin_lock_irq+0x18/0x50
softirqs last  enabled at (1383690): [<ffffffffa0e2efea>] iscsi_queuecommand+0x76a/0xa20 [libiscsi]
softirqs last disabled at (1383682): [<ffffffffa0e2e998>] iscsi_queuecommand+0x118/0xa20 [libiscsi]

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&session->frwd_lock)->rlock);
  <Interrupt>
    lock(&(&session->frwd_lock)->rlock);

 *** DEADLOCK ***

2 locks held by kworker/7:1H/206:
 #0: ffff8880d57bf928 ((wq_completion)kblockd){+.+.}, at: process_one_work+0x472/0xab0
 #1: ffff88802b9c7de8 ((work_completion)(&q->timeout_work)){+.+.}, at: process_one_work+0x476/0xab0

stack backtrace:
CPU: 7 PID: 206 Comm: kworker/7:1H Not tainted 5.5.1-dbg+ #11
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Workqueue: kblockd blk_mq_timeout_work
Call Trace:
 dump_stack+0xa5/0xe6
 print_usage_bug.cold+0x232/0x23b
 mark_lock+0x8dc/0xa70
 __lock_acquire+0xcea/0x2af0
 lock_acquire+0x106/0x240
 _raw_spin_lock+0x38/0x50
 iscsi_eh_cmd_timed_out+0xa6/0x6d0 [libiscsi]
 scsi_times_out+0xf4/0x440 [scsi_mod]
 scsi_timeout+0x1d/0x20 [scsi_mod]
 blk_mq_check_expired+0x365/0x3a0
 bt_iter+0xd6/0xf0
 blk_mq_queue_tag_busy_iter+0x3de/0x650
 blk_mq_timeout_work+0x1af/0x380
 process_one_work+0x56d/0xab0
 worker_thread+0x7a/0x5d0
 kthread+0x1bc/0x210
 ret_from_fork+0x24/0x30

Fixes: 287922eb0b18 ("block: defer timeouts to a workqueue")
Cc: Christoph Hellwig <hch@lst.de>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Lee Duncan <lduncan@suse.com>
Cc: Chris Leech <cleech@redhat.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191209173457.187370-1-bvanassche@acm.org
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30T18:26:35+00:00 Thomas Gleixner tglx@linutronix.de 2019-05-27T06:55:05+00:00 1a59d1b8e05ea6ab45f7e18897de1ef0e6bc3da6 Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details you
  should have received a copy of the gnu general public license along
  with this program if not write to the free software foundation inc
  59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi 2019-03-16T19:51:50+00:00 Linus Torvalds torvalds@linux-foundation.org 2019-03-16T19:51:50+00:00 477558d7e8d82b59a650e193a5651cf25b794dbc Pull more SCSI updates from James Bottomley: "This is the final round of mostly small fixes and performance improvements to our initial submit. The main regression fix is the ia64 simscsi build failure which was missed in the serial number elimination conversion" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (24 commits) scsi: ia64: simscsi: use request tag instead of serial_number scsi: aacraid: Fix performance issue on logical drives scsi: lpfc: Fix error codes in lpfc_sli4_pci_mem_setup() scsi: libiscsi: Hold back_lock when calling iscsi_complete_task scsi: hisi_sas: Change SERDES_CFG init value to increase reliability of HiLink scsi: hisi_sas: Send HARD RESET to clear the previous affiliation of STP target port scsi: hisi_sas: Set PHY linkrate when disconnected scsi: hisi_sas: print PHY RX errors count for later revision of v3 hw scsi: hisi_sas: Fix a timeout race of driver internal and SMP IO scsi: hisi_sas: Change return variable type in phy_up_v3_hw() scsi: qla2xxx: check for kstrtol() failure scsi: lpfc: fix 32-bit format string warning scsi: lpfc: fix unused variable warning scsi: target: tcmu: Switch to bitmap_zalloc() scsi: libiscsi: fall back to sendmsg for slab pages scsi: qla2xxx: avoid printf format warning scsi: lpfc: resolve static checker warning in lpfc_sli4_hba_unset scsi: lpfc: Correct __lpfc_sli_issue_iocb_s4 lockdep check scsi: ufs: hisi: fix ufs_hba_variant_ops passing scsi: qla2xxx: Fix panic in qla_dfs_tgt_counters_show ... 
Pull more SCSI updates from James Bottomley:
 "This is the final round of mostly small fixes and performance
  improvements to our initial submit.

  The main regression fix is the ia64 simscsi build failure which was
  missed in the serial number elimination conversion"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (24 commits)
  scsi: ia64: simscsi: use request tag instead of serial_number
  scsi: aacraid: Fix performance issue on logical drives
  scsi: lpfc: Fix error codes in lpfc_sli4_pci_mem_setup()
  scsi: libiscsi: Hold back_lock when calling iscsi_complete_task
  scsi: hisi_sas: Change SERDES_CFG init value to increase reliability of HiLink
  scsi: hisi_sas: Send HARD RESET to clear the previous affiliation of STP target port
  scsi: hisi_sas: Set PHY linkrate when disconnected
  scsi: hisi_sas: print PHY RX errors count for later revision of v3 hw
  scsi: hisi_sas: Fix a timeout race of driver internal and SMP IO
  scsi: hisi_sas: Change return variable type in phy_up_v3_hw()
  scsi: qla2xxx: check for kstrtol() failure
  scsi: lpfc: fix 32-bit format string warning
  scsi: lpfc: fix unused variable warning
  scsi: target: tcmu: Switch to bitmap_zalloc()
  scsi: libiscsi: fall back to sendmsg for slab pages
  scsi: qla2xxx: avoid printf format warning
  scsi: lpfc: resolve static checker warning in lpfc_sli4_hba_unset
  scsi: lpfc: Correct __lpfc_sli_issue_iocb_s4 lockdep check
  scsi: ufs: hisi: fix ufs_hba_variant_ops passing
  scsi: qla2xxx: Fix panic in qla_dfs_tgt_counters_show
  ...
Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi 2019-03-10T00:53:47+00:00 Linus Torvalds torvalds@linux-foundation.org 2019-03-10T00:53:47+00:00 92fff53b7191cae566be9ca6752069426c7f8241 Pull SCSI updates from James Bottomley: "This is mostly update of the usual drivers: arcmsr, qla2xxx, lpfc, hisi_sas, target/iscsi and target/core. Additionally Christoph refactored gdth as part of the dma changes. The major mid-layer change this time is the removal of bidi commands and with them the whole of the osd/exofs driver and filesystem. This is a major simplification for block and mq in particular" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (240 commits) scsi: cxgb4i: validate tcp sequence number only if chip version <= T5 scsi: cxgb4i: get pf number from lldi->pf scsi: core: replace GFP_ATOMIC with GFP_KERNEL in scsi_scan.c scsi: mpt3sas: Add missing breaks in switch statements scsi: aacraid: Fix missing break in switch statement scsi: kill command serial number scsi: csiostor: drop serial_number usage scsi: mvumi: use request tag instead of serial_number scsi: dpt_i2o: remove serial number usage scsi: st: osst: Remove negative constant left-shifts scsi: ufs-bsg: Allow reading descriptors scsi: ufs: Allow reading descriptor via raw upiu scsi: ufs-bsg: Change the calling convention for write descriptor scsi: ufs: Remove unused device quirks Revert "scsi: ufs: disable vccq if it's not needed by UFS device" scsi: megaraid_sas: Remove a bunch of set but not used variables scsi: clean obsolete return values of eh_timed_out scsi: sd: Optimal I/O size should be a multiple of physical block size scsi: MAINTAINERS: SCSI initiator and target tweaks scsi: fcoe: make use of fip_mode enum complete ... 
Pull SCSI updates from James Bottomley:
 "This is mostly update of the usual drivers: arcmsr, qla2xxx, lpfc,
  hisi_sas, target/iscsi and target/core.

  Additionally Christoph refactored gdth as part of the dma changes. The
  major mid-layer change this time is the removal of bidi commands and
  with them the whole of the osd/exofs driver and filesystem. This is a
  major simplification for block and mq in particular"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (240 commits)
  scsi: cxgb4i: validate tcp sequence number only if chip version <= T5
  scsi: cxgb4i: get pf number from lldi->pf
  scsi: core: replace GFP_ATOMIC with GFP_KERNEL in scsi_scan.c
  scsi: mpt3sas: Add missing breaks in switch statements
  scsi: aacraid: Fix missing break in switch statement
  scsi: kill command serial number
  scsi: csiostor: drop serial_number usage
  scsi: mvumi: use request tag instead of serial_number
  scsi: dpt_i2o: remove serial number usage
  scsi: st: osst: Remove negative constant left-shifts
  scsi: ufs-bsg: Allow reading descriptors
  scsi: ufs: Allow reading descriptor via raw upiu
  scsi: ufs-bsg: Change the calling convention for write descriptor
  scsi: ufs: Remove unused device quirks
  Revert "scsi: ufs: disable vccq if it's not needed by UFS device"
  scsi: megaraid_sas: Remove a bunch of set but not used variables
  scsi: clean obsolete return values of eh_timed_out
  scsi: sd: Optimal I/O size should be a multiple of physical block size
  scsi: MAINTAINERS: SCSI initiator and target tweaks
  scsi: fcoe: make use of fip_mode enum complete
  ...
scsi: libiscsi: Hold back_lock when calling iscsi_complete_task 2019-03-08T02:37:04+00:00 Lee Duncan lduncan@suse.com 2019-02-25T17:41:30+00:00 a656183e6c58a3a4d818278afab522b30a17014c If there is an error queueing an iscsi command in iscsi_queuecommand(), for example if the transport fails to take the command in sessuin->tt->xmit_task(), then the error path can call iscsi_complete_task() without first aquiring the back_lock as required. This can lead to things like ITT pool can get corrupt, resulting in duplicate ITTs being sent out. The solution is to hold the back_lock around iscsi_complete_task() calls, and to add a little commenting to help others understand when back_lock must be held. Signed-off-by: Lee Duncan <lduncan@suse.com> Acked-by: Chris Leech <cleech@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> 
If there is an error queueing an iscsi command in iscsi_queuecommand(), for
example if the transport fails to take the command in
sessuin->tt->xmit_task(), then the error path can call
iscsi_complete_task() without first aquiring the back_lock as
required. This can lead to things like ITT pool can get corrupt, resulting
in duplicate ITTs being sent out.

The solution is to hold the back_lock around iscsi_complete_task() calls,
and to add a little commenting to help others understand when back_lock
must be held.

Signed-off-by: Lee Duncan <lduncan@suse.com>
Acked-by: Chris Leech <cleech@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
scsi: libiscsi: Fix race between iscsi_xmit_task and iscsi_complete_task 2019-02-16T03:05:04+00:00 Anoob Soman anoob.soman@citrix.com 2019-02-13T05:21:39+00:00 79edd00dc6a96644d76b4a1cb97d94d49e026768 When a target sends Check Condition, whilst initiator is busy xmiting re-queued data, could lead to race between iscsi_complete_task() and iscsi_xmit_task() and eventually crashing with the following kernel backtrace. [3326150.987523] ALERT: BUG: unable to handle kernel NULL pointer dereference at 0000000000000078 [3326150.987549] ALERT: IP: [<ffffffffa05ce70d>] iscsi_xmit_task+0x2d/0xc0 [libiscsi] [3326150.987571] WARN: PGD 569c8067 PUD 569c9067 PMD 0 [3326150.987582] WARN: Oops: 0002 [#1] SMP [3326150.987593] WARN: Modules linked in: tun nfsv3 nfs fscache dm_round_robin [3326150.987762] WARN: CPU: 2 PID: 8399 Comm: kworker/u32:1 Tainted: G O 4.4.0+2 #1 [3326150.987774] WARN: Hardware name: Dell Inc. PowerEdge R720/0W7JN5, BIOS 2.5.4 01/22/2016 [3326150.987790] WARN: Workqueue: iscsi_q_13 iscsi_xmitworker [libiscsi] [3326150.987799] WARN: task: ffff8801d50f3800 ti: ffff8801f5458000 task.ti: ffff8801f5458000 [3326150.987810] WARN: RIP: e030:[<ffffffffa05ce70d>] [<ffffffffa05ce70d>] iscsi_xmit_task+0x2d/0xc0 [libiscsi] [3326150.987825] WARN: RSP: e02b:ffff8801f545bdb0 EFLAGS: 00010246 [3326150.987831] WARN: RAX: 00000000ffffffc3 RBX: ffff880282d2ab20 RCX: ffff88026b6ac480 [3326150.987842] WARN: RDX: 0000000000000000 RSI: 00000000fffffe01 RDI: ffff880282d2ab20 [3326150.987852] WARN: RBP: ffff8801f545bdc8 R08: 0000000000000000 R09: 0000000000000008 [3326150.987862] WARN: R10: 0000000000000000 R11: 000000000000fe88 R12: 0000000000000000 [3326150.987872] WARN: R13: ffff880282d2abe8 R14: ffff880282d2abd8 R15: ffff880282d2ac08 [3326150.987890] WARN: FS: 00007f5a866b4840(0000) GS:ffff88028a640000(0000) knlGS:0000000000000000 [3326150.987900] WARN: CS: e033 DS: 0000 ES: 0000 CR0: 0000000080050033 [3326150.987907] WARN: CR2: 0000000000000078 CR3: 0000000070244000 CR4: 0000000000042660 [3326150.987918] WARN: Stack: [3326150.987924] WARN: ffff880282d2ad58 ffff880282d2ab20 ffff880282d2abe8 ffff8801f545be18 [3326150.987938] WARN: ffffffffa05cea90 ffff880282d2abf8 ffff88026b59cc80 ffff88026b59cc00 [3326150.987951] WARN: ffff88022acf32c0 ffff880289491800 ffff880255a80800 0000000000000400 [3326150.987964] WARN: Call Trace: [3326150.987975] WARN: [<ffffffffa05cea90>] iscsi_xmitworker+0x2f0/0x360 [libiscsi] [3326150.987988] WARN: [<ffffffff8108862c>] process_one_work+0x1fc/0x3b0 [3326150.987997] WARN: [<ffffffff81088f95>] worker_thread+0x2a5/0x470 [3326150.988006] WARN: [<ffffffff8159cad8>] ? __schedule+0x648/0x870 [3326150.988015] WARN: [<ffffffff81088cf0>] ? rescuer_thread+0x300/0x300 [3326150.988023] WARN: [<ffffffff8108ddf5>] kthread+0xd5/0xe0 [3326150.988031] WARN: [<ffffffff8108dd20>] ? kthread_stop+0x110/0x110 [3326150.988040] WARN: [<ffffffff815a0bcf>] ret_from_fork+0x3f/0x70 [3326150.988048] WARN: [<ffffffff8108dd20>] ? kthread_stop+0x110/0x110 [3326150.988127] ALERT: RIP [<ffffffffa05ce70d>] iscsi_xmit_task+0x2d/0xc0 [libiscsi] [3326150.988138] WARN: RSP <ffff8801f545bdb0> [3326150.988144] WARN: CR2: 0000000000000078 [3326151.020366] WARN: ---[ end trace 1c60974d4678d81b ]--- Commit 6f8830f5bbab ("scsi: libiscsi: add lock around task lists to fix list corruption regression") introduced "taskqueuelock" to fix list corruption during the race, but this wasn't enough. Re-setting of conn->task to NULL, could race with iscsi_xmit_task(). iscsi_complete_task() { .... if (conn->task == task) conn->task = NULL; } conn->task in iscsi_xmit_task() could be NULL and so will be task. __iscsi_get_task(task) will crash (NullPtr de-ref), trying to access refcount. iscsi_xmit_task() { struct iscsi_task *task = conn->task; __iscsi_get_task(task); } This commit will take extra conn->session->back_lock in iscsi_xmit_task() to ensure iscsi_xmit_task() waits for iscsi_complete_task(), if iscsi_complete_task() wins the race. If iscsi_xmit_task() wins the race, iscsi_xmit_task() increments task->refcount (__iscsi_get_task) ensuring iscsi_complete_task() will not iscsi_free_task(). Signed-off-by: Anoob Soman <anoob.soman@citrix.com> Signed-off-by: Bob Liu <bob.liu@oracle.com> Acked-by: Lee Duncan <lduncan@suse.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> 
When a target sends Check Condition, whilst initiator is busy xmiting
re-queued data, could lead to race between iscsi_complete_task() and
iscsi_xmit_task() and eventually crashing with the following kernel
backtrace.

[3326150.987523] ALERT: BUG: unable to handle kernel NULL pointer dereference at 0000000000000078
[3326150.987549] ALERT: IP: [<ffffffffa05ce70d>] iscsi_xmit_task+0x2d/0xc0 [libiscsi]
[3326150.987571] WARN: PGD 569c8067 PUD 569c9067 PMD 0
[3326150.987582] WARN: Oops: 0002 [#1] SMP
[3326150.987593] WARN: Modules linked in: tun nfsv3 nfs fscache dm_round_robin
[3326150.987762] WARN: CPU: 2 PID: 8399 Comm: kworker/u32:1 Tainted: G O 4.4.0+2 #1
[3326150.987774] WARN: Hardware name: Dell Inc. PowerEdge R720/0W7JN5, BIOS 2.5.4 01/22/2016
[3326150.987790] WARN: Workqueue: iscsi_q_13 iscsi_xmitworker [libiscsi]
[3326150.987799] WARN: task: ffff8801d50f3800 ti: ffff8801f5458000 task.ti: ffff8801f5458000
[3326150.987810] WARN: RIP: e030:[<ffffffffa05ce70d>] [<ffffffffa05ce70d>] iscsi_xmit_task+0x2d/0xc0 [libiscsi]
[3326150.987825] WARN: RSP: e02b:ffff8801f545bdb0 EFLAGS: 00010246
[3326150.987831] WARN: RAX: 00000000ffffffc3 RBX: ffff880282d2ab20 RCX: ffff88026b6ac480
[3326150.987842] WARN: RDX: 0000000000000000 RSI: 00000000fffffe01 RDI: ffff880282d2ab20
[3326150.987852] WARN: RBP: ffff8801f545bdc8 R08: 0000000000000000 R09: 0000000000000008
[3326150.987862] WARN: R10: 0000000000000000 R11: 000000000000fe88 R12: 0000000000000000
[3326150.987872] WARN: R13: ffff880282d2abe8 R14: ffff880282d2abd8 R15: ffff880282d2ac08
[3326150.987890] WARN: FS: 00007f5a866b4840(0000) GS:ffff88028a640000(0000) knlGS:0000000000000000
[3326150.987900] WARN: CS: e033 DS: 0000 ES: 0000 CR0: 0000000080050033
[3326150.987907] WARN: CR2: 0000000000000078 CR3: 0000000070244000 CR4: 0000000000042660
[3326150.987918] WARN: Stack:
[3326150.987924] WARN: ffff880282d2ad58 ffff880282d2ab20 ffff880282d2abe8 ffff8801f545be18
[3326150.987938] WARN: ffffffffa05cea90 ffff880282d2abf8 ffff88026b59cc80 ffff88026b59cc00
[3326150.987951] WARN: ffff88022acf32c0 ffff880289491800 ffff880255a80800 0000000000000400
[3326150.987964] WARN: Call Trace:
[3326150.987975] WARN: [<ffffffffa05cea90>] iscsi_xmitworker+0x2f0/0x360 [libiscsi]
[3326150.987988] WARN: [<ffffffff8108862c>] process_one_work+0x1fc/0x3b0
[3326150.987997] WARN: [<ffffffff81088f95>] worker_thread+0x2a5/0x470
[3326150.988006] WARN: [<ffffffff8159cad8>] ? __schedule+0x648/0x870
[3326150.988015] WARN: [<ffffffff81088cf0>] ? rescuer_thread+0x300/0x300
[3326150.988023] WARN: [<ffffffff8108ddf5>] kthread+0xd5/0xe0
[3326150.988031] WARN: [<ffffffff8108dd20>] ? kthread_stop+0x110/0x110
[3326150.988040] WARN: [<ffffffff815a0bcf>] ret_from_fork+0x3f/0x70
[3326150.988048] WARN: [<ffffffff8108dd20>] ? kthread_stop+0x110/0x110
[3326150.988127] ALERT: RIP [<ffffffffa05ce70d>] iscsi_xmit_task+0x2d/0xc0 [libiscsi]
[3326150.988138] WARN: RSP <ffff8801f545bdb0>
[3326150.988144] WARN: CR2: 0000000000000078
[3326151.020366] WARN: ---[ end trace 1c60974d4678d81b ]---

Commit 6f8830f5bbab ("scsi: libiscsi: add lock around task lists to fix
list corruption regression") introduced "taskqueuelock" to fix list
corruption during the race, but this wasn't enough.

Re-setting of conn->task to NULL, could race with iscsi_xmit_task().
iscsi_complete_task()
{
    ....
    if (conn->task == task)
        conn->task = NULL;
}

conn->task in iscsi_xmit_task() could be NULL and so will be task.
__iscsi_get_task(task) will crash (NullPtr de-ref), trying to access
refcount.

iscsi_xmit_task()
{
    struct iscsi_task *task = conn->task;

    __iscsi_get_task(task);
}

This commit will take extra conn->session->back_lock in iscsi_xmit_task()
to ensure iscsi_xmit_task() waits for iscsi_complete_task(), if
iscsi_complete_task() wins the race.  If iscsi_xmit_task() wins the race,
iscsi_xmit_task() increments task->refcount
(__iscsi_get_task) ensuring iscsi_complete_task() will not iscsi_free_task().

Signed-off-by: Anoob Soman <anoob.soman@citrix.com>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Acked-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
scsi: libiscsi: Use scsi_[gs]et_resid() where appropriate 2019-02-12T16:13:41+00:00 Bart Van Assche bvanassche@acm.org 2019-02-08T21:24:59+00:00 960bf87a4fbe46bec1e69fcb6868f43c3c3c9456 This patch does not change any functionality. Cc: Lee Duncan <lduncan@suse.com> Cc: Chris Leech <cleech@redhat.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> 
This patch does not change any functionality.

Cc: Lee Duncan <lduncan@suse.com>
Cc: Chris Leech <cleech@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
scsi: remove bidirectional command support 2019-02-06T02:29:21+00:00 Christoph Hellwig hch@lst.de 2019-01-29T08:33:07+00:00 ae3d56d81507c33024ba7c1eae2ef433aa9bc0d5 No real need for bidi support once the OSD code is gone. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> 
No real need for bidi support once the OSD code is gone.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi 2018-12-28T22:48:06+00:00 Linus Torvalds torvalds@linux-foundation.org 2018-12-28T22:48:06+00:00 938edb8a31b976c9a92eb0cd4ff481e93f76c1f1 Pull SCSI updates from James Bottomley: "This is mostly update of the usual drivers: smarpqi, lpfc, qedi, megaraid_sas, libsas, zfcp, mpt3sas, hisi_sas. Additionally, we have a pile of annotation, unused variable and minor updates. The big API change is the updates for Christoph's DMA rework which include removing the DISABLE_CLUSTERING flag. And finally there are a couple of target tree updates" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (259 commits) scsi: isci: request: mark expected switch fall-through scsi: isci: remote_node_context: mark expected switch fall-throughs scsi: isci: remote_device: Mark expected switch fall-throughs scsi: isci: phy: Mark expected switch fall-through scsi: iscsi: Capture iscsi debug messages using tracepoints scsi: myrb: Mark expected switch fall-throughs scsi: megaraid: fix out-of-bound array accesses scsi: mpt3sas: mpt3sas_scsih: Mark expected switch fall-through scsi: fcoe: remove set but not used variable 'port' scsi: smartpqi: call pqi_free_interrupts() in pqi_shutdown() scsi: smartpqi: fix build warnings scsi: smartpqi: update driver version scsi: smartpqi: add ofa support scsi: smartpqi: increase fw status register read timeout scsi: smartpqi: bump driver version scsi: smartpqi: add smp_utils support scsi: smartpqi: correct lun reset issues scsi: smartpqi: correct volume status scsi: smartpqi: do not offline disks for transient did no connect conditions scsi: smartpqi: allow for larger raid maps ... 
Pull SCSI updates from James Bottomley:
 "This is mostly update of the usual drivers: smarpqi, lpfc, qedi,
  megaraid_sas, libsas, zfcp, mpt3sas, hisi_sas.

  Additionally, we have a pile of annotation, unused variable and minor
  updates.

  The big API change is the updates for Christoph's DMA rework which
  include removing the DISABLE_CLUSTERING flag.

  And finally there are a couple of target tree updates"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (259 commits)
  scsi: isci: request: mark expected switch fall-through
  scsi: isci: remote_node_context: mark expected switch fall-throughs
  scsi: isci: remote_device: Mark expected switch fall-throughs
  scsi: isci: phy: Mark expected switch fall-through
  scsi: iscsi: Capture iscsi debug messages using tracepoints
  scsi: myrb: Mark expected switch fall-throughs
  scsi: megaraid: fix out-of-bound array accesses
  scsi: mpt3sas: mpt3sas_scsih: Mark expected switch fall-through
  scsi: fcoe: remove set but not used variable 'port'
  scsi: smartpqi: call pqi_free_interrupts() in pqi_shutdown()
  scsi: smartpqi: fix build warnings
  scsi: smartpqi: update driver version
  scsi: smartpqi: add ofa support
  scsi: smartpqi: increase fw status register read timeout
  scsi: smartpqi: bump driver version
  scsi: smartpqi: add smp_utils support
  scsi: smartpqi: correct lun reset issues
  scsi: smartpqi: correct volume status
  scsi: smartpqi: do not offline disks for transient did no connect conditions
  scsi: smartpqi: allow for larger raid maps
  ...
scsi: iscsi: Capture iscsi debug messages using tracepoints 2018-12-21T01:03:55+00:00 Fred Herard fred.herard@oracle.com 2018-11-21T17:04:43+00:00 c2332b004907229b19a5687004290464df7c3e9d This commit enhances iscsi initiator modules to capture iscsi debug messages using linux kernel tracepoint facility: https://www.kernel.org/doc/Documentation/trace/tracepoints.txt The following tracepoint events have been created under the iscsi tracepoint event group: iscsi_dbg_conn - to capture connection debug messages (libiscsi module) iscsi_dbg_session - to capture session debug messages (libiscsi module) iscsi_dbg_eh - to capture error handling debug messages (libiscsi module) iscsi_dbg_tcp - to capture iscsi tcp debug messages (libiscsi_tcp module) iscsi_dbg_sw_tcp - to capture iscsi sw tcp debug messages (iscsi_tcp module) iscsi_dbg_trans_session - to cpature iscsi transsport sess debug messages (scsi_transport_iscsi module) iscsi_dbg_trans_conn - to capture iscsi transport conn debug messages (scsi_transport_iscsi module) [mkp: typos] Signed-off-by: Fred Herard <fred.herard@oracle.com> Reviewed-by: Rajan Shanmugavelu <rajan.shanmugavelu@oracle.com> Reviewed-by: Lee Duncan <lduncan@suse.com> Reviewed-by: Douglas Gilbert <dgilbert@interlog.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> 
This commit enhances iscsi initiator modules to capture iscsi debug
messages using linux kernel tracepoint facility:

https://www.kernel.org/doc/Documentation/trace/tracepoints.txt

The following tracepoint events have been created under the iscsi
tracepoint event group:

iscsi_dbg_conn - to capture connection debug messages (libiscsi module)

iscsi_dbg_session - to capture session debug messages (libiscsi module)

iscsi_dbg_eh - to capture error handling debug messages (libiscsi module)

iscsi_dbg_tcp - to capture iscsi tcp debug messages (libiscsi_tcp module)

iscsi_dbg_sw_tcp - to capture iscsi sw tcp debug messages (iscsi_tcp module)

iscsi_dbg_trans_session - to cpature iscsi transsport sess debug messages
	(scsi_transport_iscsi module)

iscsi_dbg_trans_conn - to capture iscsi transport conn debug messages
	(scsi_transport_iscsi module)

[mkp: typos]

Signed-off-by: Fred Herard <fred.herard@oracle.com>
Reviewed-by: Rajan Shanmugavelu <rajan.shanmugavelu@oracle.com>
Reviewed-by: Lee Duncan <lduncan@suse.com>
Reviewed-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>