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  1. 28 Jul, 2021 1 commit
    • Tejun Heo's avatar
      blk-iocost: fix operation ordering in iocg_wake_fn() · 5ab189cf
      Tejun Heo authored 
      iocg_wake_fn() open-codes wait_queue_entry removal and wakeup because it
wants the wq_entry to be always removed whether it ended up waking the
task or not. finish_wait() tests whether wq_entry needs removal without
grabbing the wait_queue lock and expects the waker to use
list_del_init_careful() after all waking operations are complete, which
iocg_wake_fn() didn't do. The operation order was wrong and the regular
list_del_init() was used.

The result is that if a waiter wakes up racing the waker, it can free pop
the wq_entry off stack before the waker is still looking at it, which can
lead to a backtrace like the following.

  [7312084.588951] general protection fault, probably for non-canonical address 0x586bf4005b2b88: 0000 [#1] SMP
  ...
  [7312084.647079] RIP: 0010:queued_spin_lock_slowpath+0x171/0x1b0
  ...
  [7312084.858314] Call Trace:
  [7312084.863548]  _raw_spin_lock_irqsave+0x22/0x30
  [7312084.872605]  try_to_wake_up+0x4c/0x4f0
  [7312084.880444]  iocg_wake_fn+0x71/0x80
  [7312084.887763]  __wake_up_common+0x71/0x140
  [7312084.895951]  iocg_kick_waitq+0xe8/0x2b0
  [7312084.903964]  ioc_rqos_throttle+0x275/0x650
  [7312084.922423]  __rq_qos_throttle+0x20/0x30
  [7312084.930608]  blk_mq_make_request+0x120/0x650
  [7312084.939490]  generic_make_request+0xca/0x310
  [7312084.957600]  submit_bio+0x173/0x200
  [7312084.981806]  swap_readpage+0x15c/0x240
  [7312084.989646]  read_swap_cache_async+0x58/0x60
  [7312084.998527]  swap_cluster_readahead+0x201/0x320
  [7312085.023432]  swapin_readahead+0x2df/0x450
  [7312085.040672]  do_swap_page+0x52f/0x820
  [7312085.058259]  handle_mm_fault+0xa16/0x1420
  [7312085.066620]  do_page_fault+0x2c6/0x5c0
  [7312085.074459]  page_fault+0x2f/0x40

Fix it by switching to list_del_init_careful() and putting it at the end.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reported-by: default avatarRik van Riel <riel@surriel.com>
Fixes: 7caa4715 ("blkcg: implement blk-iocost")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      5ab189cf
  3. 27 Jul, 2021 1 commit
  5. 23 Jul, 2021 1 commit
    • Tetsuo Handa's avatar
      loop: reintroduce global lock for safe loop_validate_file() traversal · 3ce6e1f6
      Tetsuo Handa authored 
      Commit 6cc8e743 ("loop: scale loop device by introducing per
device lock") re-opened a race window for NULL pointer dereference at
loop_validate_file() where commit 310ca162 ("block/loop: Use
global lock for ioctl() operation.") has closed.

Although we need to guarantee that other loop devices will not change
during traversal, we can't take remote "struct loop_device"->lo_mutex
inside loop_validate_file() in order to avoid AB-BA deadlock. Therefore,
introduce a global lock dedicated for loop_validate_file() which is
conditionally taken before local "struct loop_device"->lo_mutex is taken.
Signed-off-by: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Fixes: 6cc8e743 ("loop: scale loop device by introducing per device lock")
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      3ce6e1f6
  7. 22 Jul, 2021 1 commit
    • Jens Axboe's avatar
      Merge tag 'nvme-5.14-2021-07-22' of git://git.infradead.org/nvme into block-5.14 · 7054133d
      Jens Axboe authored 
      Pull NVMe fixes from Christoph:

"nvme fixes for Linux 5.14:

 - tracing fix (Keith Busch)
 - fix multipath head refcounting (Hannes Reinecke)
 - Write Zeroes vs PI fix (me)
 - drop a bogus WARN_ON (Zhihao Cheng)"

* tag 'nvme-5.14-2021-07-22' of git://git.infradead.org/nvme:
  nvme: set the PRACT bit when using Write Zeroes with T10 PI
  nvme: fix nvme_setup_command metadata trace event
  nvme: fix refcounting imbalance when all paths are down
  nvme-pci: don't WARN_ON in nvme_reset_work if ctrl.state is not RESETTING
      7054133d
  9. 21 Jul, 2021 4 commits
    • Christoph Hellwig's avatar
      nvme: set the PRACT bit when using Write Zeroes with T10 PI · aaeb7bb0
      Christoph Hellwig authored 
      When using Write Zeroes on a namespace that has protection
information enabled they behavior without the PRACT bit
counter-intuitive and will generally lead to validation failures
when reading the written blocks.  Fix this by always setting the
PRACT bit that generates matching PI data on the fly.

Fixes: 6e02318e ("nvme: add support for the Write Zeroes command")
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarKeith Busch <kbusch@kernel.org>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
      aaeb7bb0
    • Keith Busch's avatar
      nvme: fix nvme_setup_command metadata trace event · 234211b8
      Keith Busch authored 
      The metadata address is set after the trace event, so the trace is not
capturing anything useful. Rather than logging the memory address, it's
useful to know if the command carries a metadata payload, so change the
trace event to log that true/false state instead.
Signed-off-by: default avatarKeith Busch <kbusch@kernel.org>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      234211b8
    • Hannes Reinecke's avatar
      nvme: fix refcounting imbalance when all paths are down · 5396fdac
      Hannes Reinecke authored 
      When the last path to a ns_head drops the current code
removes the ns_head from the subsystem list, but will only
delete the disk itself if the last reference to the ns_head
drops. This is causing an refcounting imbalance eg when
applications have a reference to the disk, as then they'll
never get notified that the disk is in fact dead.
This patch moves the call 'del_gendisk' into nvme_mpath_check_last_path(),
ensuring that the disk can be properly removed and applications get the
appropriate notifications.
Signed-off-by: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarKeith Busch <kbusch@kernel.org>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      5396fdac
    • Zhihao Cheng's avatar
      nvme-pci: don't WARN_ON in nvme_reset_work if ctrl.state is not RESETTING · 7764656b
      Zhihao Cheng authored 
      Followling process:
nvme_probe
  nvme_reset_ctrl
    nvme_change_ctrl_state(ctrl, NVME_CTRL_RESETTING)
    queue_work(nvme_reset_wq, &ctrl->reset_work)

-------------->	nvme_remove
		  nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_DELETING)
worker_thread
  process_one_work
    nvme_reset_work
    WARN_ON(dev->ctrl.state != NVME_CTRL_RESETTING)

, which will trigger WARN_ON in nvme_reset_work():
[  127.534298] WARNING: CPU: 0 PID: 139 at drivers/nvme/host/pci.c:2594
[  127.536161] CPU: 0 PID: 139 Comm: kworker/u8:7 Not tainted 5.13.0
[  127.552518] Call Trace:
[  127.552840]  ? kvm_sched_clock_read+0x25/0x40
[  127.553936]  ? native_send_call_func_single_ipi+0x1c/0x30
[  127.555117]  ? send_call_function_single_ipi+0x9b/0x130
[  127.556263]  ? __smp_call_single_queue+0x48/0x60
[  127.557278]  ? ttwu_queue_wakelist+0xfa/0x1c0
[  127.558231]  ? try_to_wake_up+0x265/0x9d0
[  127.559120]  ? ext4_end_io_rsv_work+0x160/0x290
[  127.560118]  process_one_work+0x28c/0x640
[  127.561002]  worker_thread+0x39a/0x700
[  127.561833]  ? rescuer_thread+0x580/0x580
[  127.562714]  kthread+0x18c/0x1e0
[  127.563444]  ? set_kthread_struct+0x70/0x70
[  127.564347]  ret_from_fork+0x1f/0x30

The preceding problem can be easily reproduced by executing following
script (based on blktests suite):
test() {
  pdev="$(_get_pci_dev_from_blkdev)"
  sysfs="/sys/bus/pci/devices/${pdev}"
  for ((i = 0; i < 10; i++)); do
    echo 1 > "$sysfs/remove"
    echo 1 > /sys/bus/pci/rescan
  done
}

Since the device ctrl could be updated as an non-RESETTING state by
repeating probe/remove in userspace (which is a normal situation), we
can replace stack dumping WARN_ON with a warnning message.

Fixes: 82b057ca ("nvme-pci: fix multiple ctrl removal schedulin")
Signed-off-by: default avatarZhihao Cheng <chengzhihao1@huawei.com>
      7764656b
  11. 17 Jul, 2021 1 commit
  13. 15 Jul, 2021 4 commits
  15. 13 Jul, 2021 3 commits
    • Casey Chen's avatar
      nvme-pci: do not call nvme_dev_remove_admin from nvme_remove · 251ef6f7
      Casey Chen authored 
      nvme_dev_remove_admin could free dev->admin_q and the admin_tagset
while they are being accessed by nvme_dev_disable(), which can be called
by nvme_reset_work via nvme_remove_dead_ctrl.

Commit cb4bfda6 ("nvme-pci: fix hot removal during error handling")
intended to avoid requests being stuck on a removed controller by killing
the admin queue. But the later fix c8e9e9b7 ("nvme-pci: unquiesce
admin queue on shutdown"), together with nvme_dev_disable(dev, true)
right before nvme_dev_remove_admin() could help dispatch requests and
fail them early, so we don't need nvme_dev_remove_admin() any more.

Fixes: cb4bfda6 ("nvme-pci: fix hot removal during error handling")
Signed-off-by: default avatarCasey Chen <cachen@purestorage.com>
Reviewed-by: default avatarKeith Busch <kbusch@kernel.org>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      251ef6f7
    • Casey Chen's avatar
      nvme-pci: fix multiple races in nvme_setup_io_queues · e4b9852a
      Casey Chen authored 
      Below two paths could overlap each other if we power off a drive quickly
after powering it on. There are multiple races in nvme_setup_io_queues()
because of shutdown_lock missing and improper use of NVMEQ_ENABLED bit.

nvme_reset_work()                                nvme_remove()
  nvme_setup_io_queues()                           nvme_dev_disable()
  ...                                              ...
A1  clear NVMEQ_ENABLED bit for admin queue          lock
    retry:                                       B1  nvme_suspend_io_queues()
A2    pci_free_irq() admin queue                 B2  nvme_suspend_queue() admin queue
A3    pci_free_irq_vectors()                         nvme_pci_disable()
A4    nvme_setup_irqs();                         B3    pci_free_irq_vectors()
      ...                                            unlock
A5    queue_request_irq() for admin queue
      set NVMEQ_ENABLED bit
      ...
      nvme_create_io_queues()
A6      result = queue_request_irq();
        set NVMEQ_ENABLED bit
      ...
      fail to allocate enough IO queues:
A7      nvme_suspend_io_queues()
        goto retry

If B3 runs in between A1 and A2, it will crash if irqaction haven't
been freed by A2. B2 is supposed to free admin queue IRQ but it simply
can't fulfill the job as A1 has cleared NVMEQ_ENABLED bit.

Fix: combine A1 A2 so IRQ get freed as soon as the NVMEQ_ENABLED bit
gets cleared.

After solved #1, A2 could race with B3 if A2 is freeing IRQ while B3
is checking irqaction. A3 also could race with B2 if B2 is freeing
IRQ while A3 is checking irqaction.

Fix: A2 and A3 take lock for mutual exclusion.

A3 could race with B3 since they could run free_msi_irqs() in parallel.

Fix: A3 takes lock for mutual exclusion.

A4 could fail to allocate all needed IRQ vectors if A3 and A4 are
interrupted by B3.

Fix: A4 takes lock for mutual exclusion.

If A5/A6 happened after B2/B1, B3 will crash since irqaction is not NULL.
They are just allocated by A5/A6.

Fix: Lock queue_request_irq() and setting of NVMEQ_ENABLED bit.

A7 could get chance to pci_free_irq() for certain IO queue while B3 is
checking irqaction.

Fix: A7 takes lock.

nvme_dev->online_queues need to be protected by shutdown_lock. Since it
is not atomic, both paths could modify it using its own copy.
Co-developed-by: default avatarYuanyuan Zhong <yzhong@purestorage.com>
Signed-off-by: default avatarCasey Chen <cachen@purestorage.com>
Reviewed-by: default avatarKeith Busch <kbusch@kernel.org>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      e4b9852a
    • Prabhakar Kushwaha's avatar
      nvme-tcp: use __dev_get_by_name instead dev_get_by_name for OPT_HOST_IFACE · 8b43ced6
      Prabhakar Kushwaha authored 
      dev_get_by_name() finds network device by name but it also increases the
reference count.

If a nvme-tcp queue is present and the network device driver is removed
before nvme_tcp, we will face the following continuous log:

  "kernel:unregister_netdevice: waiting for <eth> to become free. Usage count = 2"

And rmmod further halts. Similar case arises during reboot/shutdown
with nvme-tcp queue present and both never completes.

To fix this, use __dev_get_by_name() which finds network device by
name without increasing any reference counter.

Fixes: 3ede8f72 ("nvme-tcp: allow selecting the network interface for connections")
Signed-off-by: default avatarOmkar Kulkarni <okulkarni@marvell.com>
Signed-off-by: default avatarShai Malin <smalin@marvell.com>
Signed-off-by: default avatarPrabhakar Kushwaha <pkushwaha@marvell.com>
Reviewed-by: default avatarSagi Grimberg <sagi@grimberg.me>
[hch: remove the ->ndev member entirely]
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      8b43ced6
  17. 07 Jul, 2021 3 commits
  19. 05 Jul, 2021 1 commit
  21. 02 Jul, 2021 1 commit
  23. 01 Jul, 2021 5 commits
  25. 30 Jun, 2021 14 commits
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