linux-stable.git/drivers/target, branch v5.15.78

target: remove an incorrect unmap zeroes data deduction

2022-06-09T08:22:47+00:00

[ Upstream commit 179d8609d8424529e95021df939ed7b0b82b37f1 ]

For block devices, the SCSI target drivers implements UNMAP as calls to
blkdev_issue_discard, which does not guarantee zeroing just because
Write Zeroes is supported.

Note that this does not affect the file backed path which uses
fallocate to punch holes.

Fixes: 2237498f0b5c ("target/iblock: Convert WRITE_SAME to blkdev_issue_zeroout")
Signed-off-by: Christoph Hellwig 
Reviewed-by: Martin K. Petersen 
Reviewed-by: Chaitanya Kulkarni 
Link: https://lore.kernel.org/r/20220415045258.199825-2-hch@lst.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

scsi: target: tcmu: Avoid holding XArray lock when calling lock_page

2022-06-09T08:22:40+00:00

[ Upstream commit 325d5c5fb216674296f3902a8902b942da3adc5b ]

In tcmu_blocks_release(), lock_page() is called to prevent a race causing
possible data corruption. Since lock_page() might sleep, calling it while
holding XArray lock is a bug.

To fix this, replace the xas_for_each() call with xa_for_each_range().
Since the latter does its own handling of XArray locking, the xas_lock()
and xas_unlock() calls around the original loop are no longer necessary.

The switch to xa_for_each_range() slows down the loop slightly. This is
acceptable since tcmu_blocks_release() is not relevant for performance.

Link: https://lore.kernel.org/r/20220517192913.21405-1-bostroesser@gmail.com
Fixes: bb9b9eb0ae2e ("scsi: target: tcmu: Fix possible data corruption")
Reported-by: Dan Carpenter 
Signed-off-by: Bodo Stroesser 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Sasha Levin

scsi: target: tcmu: Fix possible data corruption

2022-06-09T08:22:35+00:00

[ Upstream commit bb9b9eb0ae2e9d3f6036f0ad907c3a83dcd43485 ]

When tcmu_vma_fault() gets a page successfully, before the current context
completes page fault procedure, find_free_blocks() may run and call
unmap_mapping_range() to unmap the page. Assume that when
find_free_blocks() initially completes and the previous page fault
procedure starts to run again and completes, then one truncated page has
been mapped to userspace. But note that tcmu_vma_fault() has gotten a
refcount for the page so any other subsystem won't be able to use the page
unless the userspace address is unmapped later.

If another command subsequently runs and needs to extend dbi_thresh it may
reuse the corresponding slot for the previous page in data_bitmap. Then
though we'll allocate new page for this slot in data_area, no page fault
will happen because we have a valid map and the real request's data will be
lost.

Filesystem implementations will also run into this issue but they usually
lock the page when vm_operations_struct->fault gets a page and unlock the
page after finish_fault() completes. For truncate filesystems lock pages in
truncate_inode_pages() to protect against racing wrt. page faults.

To fix this possible data corruption scenario we can apply a method similar
to the filesystems.  For pages that are to be freed, tcmu_blocks_release()
locks and unlocks. Make tcmu_vma_fault() also lock found page under
cmdr_lock. At the same time, since tcmu_vma_fault() gets an extra page
refcount, tcmu_blocks_release() won't free pages if pages are in page fault
procedure, which means it is safe to call tcmu_blocks_release() before
unmap_mapping_range().

With these changes tcmu_blocks_release() will wait for all page faults to
be completed before calling unmap_mapping_range(). And later, if
unmap_mapping_range() is called, it will ensure stale mappings are removed.

Link: https://lore.kernel.org/r/20220421023735.9018-1-xiaoguang.wang@linux.alibaba.com
Reviewed-by: Bodo Stroesser 
Signed-off-by: Xiaoguang Wang 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Sasha Levin

scsi: target: tcmu: Fix possible page UAF

2022-04-20T07:34:15+00:00

[ Upstream commit a6968f7a367f128d120447360734344d5a3d5336 ]

tcmu_try_get_data_page() looks up pages under cmdr_lock, but it does not
take refcount properly and just returns page pointer. When
tcmu_try_get_data_page() returns, the returned page may have been freed by
tcmu_blocks_release().

We need to get_page() under cmdr_lock to avoid concurrent
tcmu_blocks_release().

Link: https://lore.kernel.org/r/20220311132206.24515-1-xiaoguang.wang@linux.alibaba.com
Reviewed-by: Bodo Stroesser 
Signed-off-by: Xiaoguang Wang 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Sasha Levin

scsi: target: iscsi: Make sure the np under each tpg is unique

2022-02-16T11:56:12+00:00

[ Upstream commit a861790afaa8b6369eee8a88c5d5d73f5799c0c6 ]

iscsit_tpg_check_network_portal() has nested for_each loops and is supposed
to return true when a match is found. However, the tpg loop will still
continue after existing the tpg_np loop. If this tpg_np is not the last the
match value will be changed.

Break the outer loop after finding a match and make sure the np under each
tpg is unique.

Link: https://lore.kernel.org/r/20220111054742.19582-1-mingzhe.zou@easystack.cn
Signed-off-by: ZouMingzhe 
Reviewed-by: Mike Christie 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Sasha Levin

scsi: target: Fix alua_tg_pt_gps_count tracking

2021-11-25T08:48:29+00:00

[ Upstream commit 1283c0d1a32bb924324481586b5d6e8e76f676ba ]

We can't free the tg_pt_gp in core_alua_set_tg_pt_gp_id() because it's
still accessed via configfs. Its release must go through the normal
configfs/refcount process.

The max alua_tg_pt_gps_count check should probably have been done in
core_alua_allocate_tg_pt_gp(), but with the current code userspace could
have created 0x0000ffff + 1 groups, but only set the id for 0x0000ffff.
Then it could have deleted a group with an ID set, and then set the ID for
that extra group and it would work ok.

It's unlikely, but just in case this patch continues to allow that type of
behavior, and just fixes the kfree() while in use bug.

Link: https://lore.kernel.org/r/20210930020422.92578-4-michael.christie@oracle.com
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Sasha Levin

scsi: target: Fix ordered tag handling

2021-11-25T08:48:29+00:00

[ Upstream commit ed1227e080990ffec5bf39006ec8a57358e6689a ]

This patch fixes the following bugs:

1. If there are multiple ordered cmds queued and multiple simple cmds
   completing, target_restart_delayed_cmds() could be called on different
   CPUs and each instance could start a ordered cmd. They could then run in
   different orders than they were queued.

2. target_restart_delayed_cmds() and target_handle_task_attr() can race
   where:

   1. target_handle_task_attr() has passed the simple_cmds == 0 check.

   2. transport_complete_task_attr() then decrements simple_cmds to 0.

   3. transport_complete_task_attr() runs target_restart_delayed_cmds() and
      it does not see any cmds on the delayed_cmd_list.

   4. target_handle_task_attr() adds the cmd to the delayed_cmd_list.

   The cmd will then end up timing out.

3. If we are sent > 1 ordered cmds and simple_cmds == 0, we can execute
   them out of order, because target_handle_task_attr() will hit that
   simple_cmds check first and return false for all ordered cmds sent.

4. We run target_restart_delayed_cmds() after every cmd completion, so if
   there is more than 1 simple cmd running, we start executing ordered cmds
   after that first cmd instead of waiting for all of them to complete.

5. Ordered cmds are not supposed to start until HEAD OF QUEUE and all older
   cmds have completed, and not just simple.

6. It's not a bug but it doesn't make sense to take the delayed_cmd_lock
   for every cmd completion when ordered cmds are almost never used. Just
   replacing that lock with an atomic increases IOPs by up to 10% when
   completions are spread over multiple CPUs and there are multiple
   sessions/ mqs/thread accessing the same device.

This patch moves the queued delayed handling to a per device work to
serialze the cmd executions for each device and adds a new counter to track
HEAD_OF_QUEUE and SIMPLE cmds. We can then check the new counter to
determine when to run the work on the completion path.

Link: https://lore.kernel.org/r/20210930020422.92578-3-michael.christie@oracle.com
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Sasha Levin

scsi: target: core: Remove from tmr_list during LUN unlink

2021-11-18T18:17:03+00:00

[ Upstream commit 12b6fcd0ea7f3cb7c3b34668fc678779924123ae ]

Currently TMF commands are removed from de_device.dev_tmf_list at the very
end of se_cmd lifecycle. However, se_lun unlinks from se_cmd upon a command
status (response) being queued in transport layer. This means that LUN and
backend device can be deleted in the meantime and a panic will occur:

target_tmr_work()
	cmd->se_tfo->queue_tm_rsp(cmd); // send abort_rsp to a wire
	transport_lun_remove_cmd(cmd) // unlink se_cmd from se_lun
- // - // - // -
<<<--- lun remove
<<<--- core backend device remove
- // - // - // -
qlt_handle_abts_completion()
  tfo->free_mcmd()
    transport_generic_free_cmd()
      target_put_sess_cmd()
        core_tmr_release_req() {
          if (dev) { // backend device, can not be null
            spin_lock_irqsave(&dev->se_tmr_lock, flags); //<<<--- CRASH

Call Trace:
NIP [c000000000e1683c] _raw_spin_lock_irqsave+0x2c/0xc0
LR [c00800000e433338] core_tmr_release_req+0x40/0xa0 [target_core_mod]
Call Trace:
(unreliable)
0x0
target_put_sess_cmd+0x2a0/0x370 [target_core_mod]
transport_generic_free_cmd+0x6c/0x1b0 [target_core_mod]
tcm_qla2xxx_complete_mcmd+0x28/0x50 [tcm_qla2xxx]
process_one_work+0x2c4/0x5c0
worker_thread+0x88/0x690

For the iSCSI protocol this is easily reproduced:

 - Send some SCSI sommand

 - Send Abort of that command over iSCSI

 - Remove LUN on target

 - Send next iSCSI command to acknowledge the Abort_Response

 - Target panics

There is no need to keep the command in tmr_list until response completion,
so move the removal from tmr_list from the response completion to the
response queueing when the LUN is unlinked.  Move the removal from state
list too as it is a subject to the same race condition.

Link: https://lore.kernel.org/r/20211018135753.15297-1-d.bogdanov@yadro.com
Fixes: c66ac9db8d4a ("[SCSI] target: Add LIO target core v4.0.0-rc6")
Reviewed-by: Roman Bolshakov 
Reviewed-by: Mike Christie 
Signed-off-by: Dmitry Bogdanov 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Sasha Levin

scsi: target: Fix spelling mistake "CONFLIFT" -> "CONFLICT"

2021-09-22T04:17:29+00:00

There is a spelling mistake in a dev_err message. Fix it.

Link: https://lore.kernel.org/r/20210920183206.17477-1-colin.king@canonical.com
Signed-off-by: Colin Ian King 
Signed-off-by: Martin K. Petersen

scsi: target: Fix the pgr/alua_support_store functions

2021-09-14T02:15:46+00:00

Commit 356ba2a8bc8d ("scsi: target: tcmu: Make pgr_support and alua_support
attributes writable") introduced support for changeable alua_support and
pgr_support target attributes. These can only be changed if the backstore
is user-backed, otherwise the kernel returns -EINVAL.

This triggers a warning in the targetcli/rtslib code when performing a
target restore that includes non-userbacked backstores:

  # targetctl restore
  Storage Object block/storage1: Cannot set attribute alua_support:
  [Errno 22] Invalid argument, skipped
  Storage Object block/storage1: Cannot set attribute pgr_support:
  [Errno 22] Invalid argument, skipped

Fix this warning by returning an error code only if we are really going to
flip the PGR/ALUA bit in the transport_flags field, otherwise we will do
nothing and return success.

Return ENOSYS instead of EINVAL if the pgr/alua attributes can not be
changed, this way it will be possible for userspace to understand if the
operation failed because an invalid value has been passed to strtobool() or
because the attributes are fixed.

Fixes: 356ba2a8bc8d ("scsi: target: tcmu: Make pgr_support and alua_support attributes writable")
Link: https://lore.kernel.org/r/20210906151809.52811-1-mlombard@redhat.com
Reviewed-by: Bodo Stroesser 
Signed-off-by: Maurizio Lombardi 
Signed-off-by: Martin K. Petersen