linux-stable.git/drivers/block/null_blk, branch v6.18.50

null_blk: fix UBSAN shift-out-of-bounds when zone_size is 0 or overflows

2026-08-27T12:32:50+00:00

commit 95491fb05105b61050cb623a5e0227eb26aa3525 upstream.

null_zone_no() does sect >> ilog2(dev->zone_size_sects). When
zone_size_sects is 0, ilog2(0) returns -1, producing shift exponent -1
which UBSAN reports as shift-out-of-bounds.

  UBSAN: shift-out-of-bounds in drivers/block/null_blk/zoned.c:21:14
  shift exponent -1 is negative
  Call Trace:
   null_zone_no drivers/block/null_blk/zoned.c:21 [inline]
   null_process_zoned_cmd+0xf76/0xf80 drivers/block/null_blk/zoned.c:728
   null_handle_cmd drivers/block/null_blk/main.c:1455 [inline]
   null_queue_rq+0x8bc/0xe70 drivers/block/null_blk/main.c:1703
   __blk_mq_issue_directly block/blk-mq.c:2694 [inline]
   blk_mq_try_issue_directly+0x3f4/0x880 block/blk-mq.c:2754
   blk_mq_submit_bio+0x20c0/0x2a40 block/blk-mq.c:3208
   submit_bio_noacct_nocheck+0x2f4/0xa40 block/blk-core.c:790
   block_read_full_folio+0x7a6/0x810 fs/buffer.c:2463
   filemap_read_folio+0x12c/0x3a0 mm/filemap.c:2510
   read_part_sector+0xb6/0x2b0 block/partitions/core.c:724
   adfspart_check_ICS+0xb1/0x960 block/partitions/acorn.c:357
   check_partition block/partitions/core.c:143 [inline]
   blk_add_partitions block/partitions/core.c:591 [inline]
   bdev_disk_changed+0x851/0x17a0 block/partitions/core.c:695
   blkdev_get_whole+0x372/0x510 block/bdev.c:751
   add_disk_final block/genhd.c:412 [inline]
   add_disk_fwnode+0x24b/0x3a0 block/genhd.c:606
   null_add_dev+0x130b/0x1d70 drivers/block/null_blk/main.c:2052
   nullb_device_power_store+0x240/0x380 drivers/block/null_blk/main.c:501
   configfs_write_iter+0x337/0x430 fs/configfs/file.c:229

Syzkaller triggers this by creating a zoned null_blk device via
configfs. The Call Trace shows configfs_write_iter in configfs/file.c
handling a write to power file, which calls nullb_device_power_store in
main.c, which calls null_add_dev in main.c, which calls add_disk in
genhd.c, which triggers partition scan via bdev_disk_changed in
partitions/core.c.

A zoned null_blk device with zone_size 0 should not be legal. Existing
code tries to reject it via is_power_of_2() check in zoned.c and
!zone_size check in main.c, but syzkaller can still reach
null_zone_no() with zone_size_sects 0 via two paths:

1. Direct 0 via configfs: zone_size attribute store in main.c has
NULLB_DEVICE_ATTR(zone_size, ulong, NULL) with no validation callback,
so echo 0 > zone_size succeeds before power store. If zoned is false
at power store time, the !zone_size check in main.c is skipped, and
later zoned set true leaves zone_size 0.

2. Large value overflow: mb_to_sects() in zoned.c does
(sector_t)mb * SZ_1M >> SECTOR_SHIFT which is mb * 2048. If mb is
1UL << 53 (9PB), mb * 2048 overflows 64-bit to 0. The value is
power-of-two so is_power_of_2() passes, but mb_to_sects() returns 0.

Check for zero zone_size explicitly in null_init_zoned_dev() in
zoned.c, returning -EINVAL with "must be non-zero power-of-two".
Check for zero zone_size_sects after mb_to_sects() conversion,
returning -EINVAL for overflow case. Keep defensive check in
null_zone_no() returning 0 for zero sectors to avoid shift out-of-bounds
even if  zero slips through.

This change should be safe because zone_size is set once in
null_init_zoned_dev() under device lock and never changes after, and 0
is never valid for a zoned device. Returning -EINVAL at init time fails
device creation early with clear error, while defensive return 0 in
null_zone_no() makes zoned command fail via offline zone check.
No new locking is introduced.

Reported-by: syzbot+abd6a8dca0f2b7726060@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=abd6a8dca0f2b7726060
Link: https://lore.kernel.org/all/6a75205c.01d0871a.3a0d52.0033.GAE@google.com/
Fixes: 8a3cf049af68 ("null_blk: add zoned block device emulation")
Cc: stable@vger.kernel.org
Assisted-by: Hermes:muse-spark-1.2 syzkaller
Signed-off-by: Rik van Riel 
Reviewed-by: Damien Le Moal 
Link: https://patch.msgid.link/20260808114239.69167f68@fangorn
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

null_blk: fix kmemleak by releasing references to fault configfs items

2026-01-23T10:21:24+00:00

commit 40b94ec7edbbb867c4e26a1a43d2b898f04b93c5 upstream.

When CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION is enabled, the null-blk
driver sets up fault injection support by creating the timeout_inject,
requeue_inject, and init_hctx_fault_inject configfs items as children
of the top-level nullbX configfs group.

However, when the nullbX device is removed, the references taken to
these fault-config configfs items are not released. As a result,
kmemleak reports a memory leak, for example:

unreferenced object 0xc00000021ff25c40 (size 32):
  comm "mkdir", pid 10665, jiffies 4322121578
  hex dump (first 32 bytes):
    69 6e 69 74 5f 68 63 74 78 5f 66 61 75 6c 74 5f  init_hctx_fault_
    69 6e 6a 65 63 74 00 88 00 00 00 00 00 00 00 00  inject..........
  backtrace (crc 1a018c86):
    __kmalloc_node_track_caller_noprof+0x494/0xbd8
    kvasprintf+0x74/0xf4
    config_item_set_name+0xf0/0x104
    config_group_init_type_name+0x48/0xfc
    fault_config_init+0x48/0xf0
    0xc0080000180559e4
    configfs_mkdir+0x304/0x814
    vfs_mkdir+0x49c/0x604
    do_mkdirat+0x314/0x3d0
    sys_mkdir+0xa0/0xd8
    system_call_exception+0x1b0/0x4f0
    system_call_vectored_common+0x15c/0x2ec

Fix this by explicitly releasing the references to the fault-config
configfs items when dropping the reference to the top-level nullbX
configfs group.

Cc: stable@vger.kernel.org
Reviewed-by: Chaitanya Kulkarni 
Fixes: bb4c19e030f4 ("block: null_blk: make fault-injection dynamically configurable per device")
Signed-off-by: Nilay Shroff 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

null_blk: set dma alignment to logical block size

2025-10-31T15:03:12+00:00

This driver assumes that bio vectors are memory aligned to the logical
block size, so set the queue limit to reflect that.

Unless we set up the limit based on the logical block size, we will go
out of page bounds in copy_to_nullb / copy_from_nullb.

Apparently this wasn't noticed so far because none of the tests generate
such buffers, but since commit 851c4c96db00 ("xfs: implement
XFS_IOC_DIOINFO in terms of vfs_getattr") xfstests generates unaligned
I/O, which now lead to memory corruption when using null_blk devices
with 4k block size.

Fixes: bf8d08532bc1 ("iomap: add support for dma aligned direct-io")
Fixes: b1a000d3b8ec ("block: relax direct io memory alignment")
Reviewed-by: Christoph Hellwig 
Reviewed-by: Keith Busch 
Signed-off-by: Hans Holmberg 
Reviewed-by: Johannes Thumshirn 
Signed-off-by: Jens Axboe

null_blk: Fix the description of the cache_size module argument

2025-09-08T14:06:10+00:00

When executing modinfo null_blk, there is an error in the description
of module parameter mbps, and the output information of cache_size is
incomplete.The output of modinfo before and after applying this patch
is as follows:

Before:
[...]
parm:           cache_size:ulong
[...]
parm:           mbps:Cache size in MiB for memory-backed device.
		Default: 0 (none) (uint)
[...]

After:
[...]
parm:           cache_size:Cache size in MiB for memory-backed device.
		Default: 0 (none) (ulong)
[...]
parm:           mbps:Limit maximum bandwidth (in MiB/s).
		Default: 0 (no limit) (uint)
[...]

Fixes: 058efe000b31 ("null_blk: add module parameters for 4 options")
Signed-off-by: Genjian Zhang 
Reviewed-by: Damien Le Moal 
Signed-off-by: Jens Axboe

null_blk: use memzero_page()

2025-07-10T05:42:08+00:00

memzero_page() is the new name for zero_user().

Link: https://lkml.kernel.org/r/20250612143443.2848197-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: Alex Markuze 
Cc: Christoph Hellwig 
Cc: Ilya Dryomov 
Cc: Ira Weiny 
Cc: Jens Axboe 
Cc: Xiubo Li 
Cc: Dan Carpenter 
Cc: Viacheslav Dubeyko 
Signed-off-by: Andrew Morton

null_blk: Use strscpy() instead of strscpy_pad() in null_add_dev()

2025-04-11T13:10:46+00:00

blk_mq_alloc_disk() already zero-initializes the destination buffer,
making strscpy() sufficient for safely copying the disk's name. The
additional NUL-padding performed by strscpy_pad() is unnecessary.

If the destination buffer has a fixed length, strscpy() automatically
determines its size using sizeof() when the argument is omitted. This
makes the explicit size argument unnecessary.

The source string is also NUL-terminated and meets the __must_be_cstr()
requirement of strscpy().

No functional changes intended.

Signed-off-by: Thorsten Blum 
Reviewed-by: Zhu Yanjun 
Reviewed-by: Damien Le Moal 
Link: https://lore.kernel.org/r/20250410154727.883207-1-thorsten.blum@linux.dev
Signed-off-by: Jens Axboe

Merge tag 'for-6.15/block-20250322' of git://git.kernel.dk/linux

2025-03-27T01:08:55+00:00

Pull block updates from Jens Axboe:

 - Fixes for integrity handling

 - NVMe pull request via Keith:
      - Secure concatenation for TCP transport (Hannes)
      - Multipath sysfs visibility (Nilay)
      - Various cleanups (Qasim, Baruch, Wang, Chen, Mike, Damien, Li)
      - Correct use of 64-bit BARs for pci-epf target (Niklas)
      - Socket fix for selinux when used in containers (Peijie)

 - MD pull request via Yu:
      - fix recovery can preempt resync (Li Nan)
      - fix md-bitmap IO limit (Su Yue)
      - fix raid10 discard with REQ_NOWAIT (Xiao Ni)
      - fix raid1 memory leak (Zheng Qixing)
      - fix mddev uaf (Yu Kuai)
      - fix raid1,raid10 IO flags (Yu Kuai)
      - some refactor and cleanup (Yu Kuai)

 - Series cleaning up and fixing bugs in the bad block handling code

 - Improve support for write failure simulation in null_blk

 - Various lock ordering fixes

 - Fixes for locking for debugfs attributes

 - Various ublk related fixes and improvements

 - Cleanups for blk-rq-qos wait handling

 - blk-throttle fixes

 - Fixes for loop dio and sync handling

 - Fixes and cleanups for the auto-PI code

 - Block side support for hardware encryption keys in blk-crypto

 - Various cleanups and fixes

* tag 'for-6.15/block-20250322' of git://git.kernel.dk/linux: (105 commits)
  nvmet: replace max(a, min(b, c)) by clamp(val, lo, hi)
  nvme-tcp: fix selinux denied when calling sock_sendmsg
  nvmet: pci-epf: Always configure BAR0 as 64-bit
  nvmet: Remove duplicate uuid_copy
  nvme: zns: Simplify nvme_zone_parse_entry()
  nvmet: pci-epf: Remove redundant 'flush_workqueue()' calls
  nvmet-fc: Remove unused functions
  nvme-pci: remove stale comment
  nvme-fc: Utilise min3() to simplify queue count calculation
  nvme-multipath: Add visibility for queue-depth io-policy
  nvme-multipath: Add visibility for numa io-policy
  nvme-multipath: Add visibility for round-robin io-policy
  nvmet: add tls_concat and tls_key debugfs entries
  nvmet-tcp: support secure channel concatenation
  nvmet: Add 'sq' argument to alloc_ctrl_args
  nvme-fabrics: reset admin connection for secure concatenation
  nvme-tcp: request secure channel concatenation
  nvme-keyring: add nvme_tls_psk_refresh()
  nvme: add nvme_auth_derive_tls_psk()
  nvme: add nvme_auth_generate_digest()
  ...

Merge tag 'timers-cleanups-2025-03-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-03-25T17:54:15+00:00

Pull timer cleanups from Thomas Gleixner:
 "A treewide hrtimer timer cleanup

  hrtimers are initialized with hrtimer_init() and a subsequent store to
  the callback pointer. This turned out to be suboptimal for the
  upcoming Rust integration and is obviously a silly implementation to
  begin with.

  This cleanup replaces the hrtimer_init(T); T->function = cb; sequence
  with hrtimer_setup(T, cb);

  The conversion was done with Coccinelle and a few manual fixups.

  Once the conversion has completely landed in mainline, hrtimer_init()
  will be removed and the hrtimer::function becomes a private member"

* tag 'timers-cleanups-2025-03-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (100 commits)
  wifi: rt2x00: Switch to use hrtimer_update_function()
  io_uring: Use helper function hrtimer_update_function()
  serial: xilinx_uartps: Use helper function hrtimer_update_function()
  ASoC: fsl: imx-pcm-fiq: Switch to use hrtimer_setup()
  RDMA: Switch to use hrtimer_setup()
  virtio: mem: Switch to use hrtimer_setup()
  drm/vmwgfx: Switch to use hrtimer_setup()
  drm/xe/oa: Switch to use hrtimer_setup()
  drm/vkms: Switch to use hrtimer_setup()
  drm/msm: Switch to use hrtimer_setup()
  drm/i915/request: Switch to use hrtimer_setup()
  drm/i915/uncore: Switch to use hrtimer_setup()
  drm/i915/pmu: Switch to use hrtimer_setup()
  drm/i915/perf: Switch to use hrtimer_setup()
  drm/i915/gvt: Switch to use hrtimer_setup()
  drm/i915/huc: Switch to use hrtimer_setup()
  drm/amdgpu: Switch to use hrtimer_setup()
  stm class: heartbeat: Switch to use hrtimer_setup()
  i2c: Switch to use hrtimer_setup()
  iio: Switch to use hrtimer_setup()
  ...

block: change blk_mq_add_to_batch() third argument type to bool

2025-03-12T14:26:36+00:00

Commit 1f47ed294a2b ("block: cleanup and fix batch completion adding
conditions") modified the evaluation criteria for the third argument,
'ioerror', in the blk_mq_add_to_batch() function. Initially, the
function had checked if 'ioerror' equals zero. Following the commit, it
started checking for negative error values, with the presumption that
such values, for instance -EIO, would be passed in.

However, blk_mq_add_to_batch() callers do not pass negative error
values. Instead, they pass status codes defined in various ways:

- NVMe PCI and Apple drivers pass NVMe status code
- virtio_blk driver passes the virtblk request header status byte
- null_blk driver passes blk_status_t

These codes are either zero or positive, therefore the revised check
fails to function as intended. Specifically, with the NVMe PCI driver,
this modification led to the failure of the blktests test case nvme/039.
In this test scenario, errors are artificially injected to the NVMe
driver, resulting in positive NVMe status codes passed to
blk_mq_add_to_batch(), which unexpectedly processes the failed I/O in a
batch. Hence the failure.

To correct the ioerror check within blk_mq_add_to_batch(), make all
callers to uniformly pass the argument as boolean. Modify the callers to
check their specific status codes and pass the boolean value 'is_error'.
Also describe the arguments of blK_mq_add_to_batch as kerneldoc.

Fixes: 1f47ed294a2b ("block: cleanup and fix batch completion adding conditions")
Signed-off-by: Shin'ichiro Kawasaki 
Link: https://lore.kernel.org/r/20250311104359.1767728-3-shinichiro.kawasaki@wdc.com
[axboe: fold in documentation update]
Signed-off-by: Jens Axboe

badblocks: use sector_t instead of int to avoid truncation of badblocks length

2025-03-06T15:04:52+00:00

There is a truncation of badblocks length issue when set badblocks as
follow:

echo "2055 4294967299" > bad_blocks
cat bad_blocks
2055 3

Change 'sectors' argument type from 'int' to 'sector_t'.

This change avoids truncation of badblocks length for large sectors by
replacing 'int' with 'sector_t' (u64), enabling proper handling of larger
disk sizes and ensuring compatibility with 64-bit sector addressing.

Fixes: 9e0e252a048b ("badblocks: Add core badblock management code")
Signed-off-by: Zheng Qixing 
Reviewed-by: Yu Kuai 
Acked-by: Coly Li 
Link: https://lore.kernel.org/r/20250227075507.151331-13-zhengqixing@huaweicloud.com
Signed-off-by: Jens Axboe