linux-stable.git/drivers/s390/block, branch linux-rolling-lts

s390/dasd: Propagate partial completion length across ERP recovery

2026-09-07T15:22:48+00:00

commit 6fb5ba2e7e43173a3761e46f091070a8185efa14 upstream.

dasd_default_erp_postaction() copies the timing and device state from
the finished ERP request back to the original request but drops
proc_bytes. A request that was partially completed, an ESE read of a
not-yet-allocated track returns fewer bytes than requested, and then
recovered through the ERP chain loses its partial-completion length.
__dasd_cleanup_cqr() then sees proc_bytes == 0 and completes the whole
request instead of requeueing the remainder, silently returning zeroed
data for the part that was never read.

Carry proc_bytes over to the original request like the other
per-request state.

Fixes: 5e6bdd37c552 ("s390/dasd: fix data corruption for thin provisioned devices")
Cc: stable@vger.kernel.org
Reviewed-by: Jan Höppner 
Signed-off-by: Stefan Haberland 
Link: https://patch.msgid.link/20260805111612.1285190-3-sth@linux.ibm.com
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

s390/dasd: Guard sysfs discipline callbacks against unallocated private data

2026-09-07T15:22:48+00:00

commit 2a1780f9fc2493bd34c418a0be6fc58943afcecf upstream.

Several sysfs show/store handlers call a discipline callback that
dereferences device->private, either directly or through the
DASD_DEFINE_ATTR() macro. During dasd_generic_set_online() the discipline
is assigned before check_device() allocates device->private, so an
unprivileged read of one of these world-readable attributes in that window
dereferences a NULL pointer and panics.

Guard the dereference inside each callback that actually touches
device->private.

Fixes: c729696bcf8b ("s390/dasd: Recognise data for ESE volumes")
Cc: stable@vger.kernel.org
Reviewed-by: Jan Höppner 
Signed-off-by: Stefan Haberland 
Link: https://patch.msgid.link/20260805111612.1285190-4-sth@linux.ibm.com
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

s390/dasd: Do not complete a failed ESE read as successful

2026-09-07T15:22:48+00:00

commit cddb447c62466f3076938ce120028d7b591f9f37 upstream.

dasd_int_handler() completes an NRF read of an unallocated ESE track by
calling ese_read() and unconditionally marking the request
DASD_CQR_SUCCESS. dasd_eckd_ese_read() can return an error before it has
zeroed the destination buffer: a failed sense-data parse or a current
track outside the requested range both return early, leaving the
destination pages untouched. The request is still completed successfully,
so the block layer is handed stale / uninitialized memory instead of
zeros.

Check the ese_read() return value and fail the request through the normal
error path instead of forcing DASD_CQR_SUCCESS.

Fixes: 5e6bdd37c552 ("s390/dasd: fix data corruption for thin provisioned devices")
Cc: stable@vger.kernel.org
Reviewed-by: Jan Höppner 
Signed-off-by: Stefan Haberland 
Link: https://patch.msgid.link/20260805111612.1285190-2-sth@linux.ibm.com
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

s390/dasd: Fix undersized format-check buffer

2026-08-09T18:25:19+00:00

commit 7f40b346462f563a0d6e841a77b5163d2a882a04 upstream.

fmt_buffer_size in dasd_eckd_check_device_format() is declared as
int, even though one of the multiplicands, sizeof(struct eckd_count),
is a size_t. The expression

    trkcount * rpt_max * sizeof(struct eckd_count)

is therefore correctly evaluated at 64-bit width, but the result is
silently truncated when it is stored back into the 32-bit
fmt_buffer_size variable. For a sufficiently large track range
(start_unit/stop_unit are caller-controlled) this truncation
yields a buffer size far smaller than the number of tracks actually
requested. kzalloc() then succeeds with an undersized allocation,
while the subsequent channel program build still operates on the
untruncated track count and writes past the end of that buffer.

Compute the buffer size with check_mul_overflow() and keep it in a
size_t, so that a value that no longer fits results in -EINVAL
instead of a silently truncated allocation size.

Fixes: 8fd575200db5 ("s390/dasd: Add new ioctl BIODASDCHECKFMT")
Cc: stable@vger.kernel.org #4.7
Reviewed-by: Jan Höppner 
Signed-off-by: Stefan Haberland 
Link: https://patch.msgid.link/20260727142840.567286-4-sth@linux.ibm.com
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

s390/dasd: Fix potential NULL pointer dereference

2026-08-09T18:25:19+00:00

commit 9973026f572db6b67570cadc30942f3014e41079 upstream.

dasd_release_space() checks the implementation of the is_ese()
discipline function before calling it to determine if a given device is
an ESE DASD.

The current usage of the logical AND operator will lead to a NULL
pointer dereference as the function is called even if the function
pointer is NULL.

Fix this by using the logical OR operator.

Fixes: 91dc4a197569 ("s390/dasd: Add new ioctl to release space")
Cc: stable@vger.kernel.org # v5.3+
Reported-by: Vasily Gorbik 
Acked-by: Eduard Shishkin 
Reviewed-by: Stefan Haberland 
Signed-off-by: Jan Höppner 
Signed-off-by: Stefan Haberland 
Link: https://patch.msgid.link/20260727142840.567286-3-sth@linux.ibm.com
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

s390/dasd: Copy detected format information to secondary device

2026-03-19T15:08:43+00:00

commit 4c527c7e030672efd788d0806d7a68972a7ba3c1 upstream.

During online processing for a DASD device an IO operation is started to
determine the format of the device. CDL format contains specifically
sized blocks at the beginning of the disk.

For a PPRC secondary device no real IO operation is possible therefore
this IO request can not be started and this step is skipped for online
processing of secondary devices. This is generally fine since the
secondary is a copy of the primary device.

In case of an additional partition detection that is run after a swap
operation the format information is needed to properly drive partition
detection IO.

Currently the information is not passed leading to IO errors during
partition detection and a wrongly detected partition table which in turn
might lead to data corruption on the disk with the wrong partition table.

Fix by passing the format information from primary to secondary device.

Fixes: 413862caad6f ("s390/dasd: add copy pair swap capability")
Cc: stable@vger.kernel.org #6.1
Reviewed-by: Jan Hoeppner 
Acked-by: Eduard Shishkin 
Signed-off-by: Stefan Haberland 
Link: https://patch.msgid.link/20260310142330.4080106-3-sth@linux.ibm.com
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

s390/dasd: Move quiesce state with pprc swap

2026-03-19T15:08:43+00:00

commit 40e9cd4ae8ec43b107ed2bff422a8fa39dcf4e4b upstream.

Quiesce and resume is a mechanism to suspend operations on DASD devices.
In the context of a controlled copy pair swap operation, the quiesce
operation is usually issued before the actual swap and a resume
afterwards.

During the swap operation, the underlying device is exchanged. Therefore,
the quiesce flag must be moved to the secondary device to ensure a
consistent quiesce state after the swap.

The secondary device itself cannot be suspended separately because there
is no separate block device representation for it.

Fixes: 413862caad6f ("s390/dasd: add copy pair swap capability")
Cc: stable@vger.kernel.org #6.1
Reviewed-by: Jan Hoeppner 
Signed-off-by: Stefan Haberland 
Link: https://patch.msgid.link/20260310142330.4080106-2-sth@linux.ibm.com
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

s390/dasd: Fix gendisk parent after copy pair swap

2026-01-02T11:57:08+00:00

commit c943bfc6afb8d0e781b9b7406f36caa8bbf95cb9 upstream.

After a copy pair swap the block device's "device" symlink points to
the secondary CCW device, but the gendisk's parent remained the
primary, leaving /sys/block/ under the wrong parent.

Move the gendisk to the secondary's device with device_move(), keeping
the sysfs topology consistent after the swap.

Fixes: 413862caad6f ("s390/dasd: add copy pair swap capability")
Cc: stable@vger.kernel.org #6.1
Reviewed-by: Jan Hoeppner 
Signed-off-by: Stefan Haberland 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'for-6.18/block-20250929' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux

2025-10-02T17:16:56+00:00

Pull block updates from Jens Axboe:

 - NVMe pull request via Keith:
     - FC target fixes (Daniel)
     - Authentication fixes and updates (Martin, Chris)
     - Admin controller handling (Kamaljit)
     - Target lockdep assertions (Max)
     - Keep-alive updates for discovery (Alastair)
     - Suspend quirk (Georg)

 - MD pull request via Yu:
     - Add support for a lockless bitmap.

       A key feature for the new bitmap are that the IO fastpath is
       lockless. If a user issues lots of write IO to the same bitmap
       bit in a short time, only the first write has additional overhead
       to update bitmap bit, no additional overhead for the following
       writes.

       By supporting only resync or recover written data, means in the
       case creating new array or replacing with a new disk, there is no
       need to do a full disk resync/recovery.

 - Switch ->getgeo() and ->bios_param() to using struct gendisk rather
   than struct block_device.

 - Rust block changes via Andreas. This series adds configuration via
   configfs and remote completion to the rnull driver. The series also
   includes a set of changes to the rust block device driver API: a few
   cleanup patches, and a few features supporting the rnull changes.

   The series removes the raw buffer formatting logic from
   `kernel::block` and improves the logic available in `kernel::string`
   to support the same use as the removed logic.

 - floppy arch cleanups

 - Reduce the number of dereferencing needed for ublk commands

 - Restrict supported sockets for nbd. Mostly done to eliminate a class
   of issues perpetually reported by syzbot, by using nonsensical socket
   setups.

 - A few s390 dasd block fixes

 - Fix a few issues around atomic writes

 - Improve DMA interation for integrity requests

 - Improve how iovecs are treated with regards to O_DIRECT aligment
   constraints.

   We used to require each segment to adhere to the constraints, now
   only the request as a whole needs to.

 - Clean up and improve p2p support, enabling use of p2p for metadata
   payloads

 - Improve locking of request lookup, using SRCU where appropriate

 - Use page references properly for brd, avoiding very long RCU sections

 - Fix ordering of recursively submitted IOs

 - Clean up and improve updating nr_requests for a live device

 - Various fixes and cleanups

* tag 'for-6.18/block-20250929' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (164 commits)
  s390/dasd: enforce dma_alignment to ensure proper buffer validation
  s390/dasd: Return BLK_STS_INVAL for EINVAL from do_dasd_request
  ublk: remove redundant zone op check in ublk_setup_iod()
  nvme: Use non zero KATO for persistent discovery connections
  nvmet: add safety check for subsys lock
  nvme-core: use nvme_is_io_ctrl() for I/O controller check
  nvme-core: do ioccsz/iorcsz validation only for I/O controllers
  nvme-core: add method to check for an I/O controller
  blk-cgroup: fix possible deadlock while configuring policy
  blk-mq: fix null-ptr-deref in blk_mq_free_tags() from error path
  blk-mq: Fix more tag iteration function documentation
  selftests: ublk: fix behavior when fio is not installed
  ublk: don't access ublk_queue in ublk_unmap_io()
  ublk: pass ublk_io to __ublk_complete_rq()
  ublk: don't access ublk_queue in ublk_need_complete_req()
  ublk: don't access ublk_queue in ublk_check_commit_and_fetch()
  ublk: don't pass ublk_queue to ublk_fetch()
  ublk: don't access ublk_queue in ublk_config_io_buf()
  ublk: don't access ublk_queue in ublk_check_fetch_buf()
  ublk: pass q_id and tag to __ublk_check_and_get_req()
  ...

s390/dasd: enforce dma_alignment to ensure proper buffer validation

2025-09-25T16:34:30+00:00

The block layer validates buffer alignment using the device's
dma_alignment value. If dma_alignment is smaller than
logical_block_size(bp_block) -1, misaligned buffer incorrectly pass
validation and propagate to the lower-level driver.

This patch adjusts dma_alignment to be at least logical_block_size -1,
ensuring that misalignment buffers are properly rejected at the block
layer and do not reach the DASD driver unnecessarily.

Fixes: 2a07bb64d801 ("s390/dasd: Remove DMA alignment")
Reviewed-by: Stefan Haberland 
Cc: stable@vger.kernel.org #6.11+
Signed-off-by: Jaehoon Kim 
Signed-off-by: Stefan Haberland 
Signed-off-by: Jens Axboe