linux-stable.git/drivers/md, branch linux-5.4.y

dm: fix NULL pointer dereference in __dm_suspend()

2025-10-29T12:59:55+00:00

[ Upstream commit 8d33a030c566e1f105cd5bf27f37940b6367f3be ]

There is a race condition between dm device suspend and table load that
can lead to null pointer dereference. The issue occurs when suspend is
invoked before table load completes:

BUG: kernel NULL pointer dereference, address: 0000000000000054
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 6 PID: 6798 Comm: dmsetup Not tainted 6.6.0-g7e52f5f0ca9b #62
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014
RIP: 0010:blk_mq_wait_quiesce_done+0x0/0x50
Call Trace:
  
  blk_mq_quiesce_queue+0x2c/0x50
  dm_stop_queue+0xd/0x20
  __dm_suspend+0x130/0x330
  dm_suspend+0x11a/0x180
  dev_suspend+0x27e/0x560
  ctl_ioctl+0x4cf/0x850
  dm_ctl_ioctl+0xd/0x20
  vfs_ioctl+0x1d/0x50
  __se_sys_ioctl+0x9b/0xc0
  __x64_sys_ioctl+0x19/0x30
  x64_sys_call+0x2c4a/0x4620
  do_syscall_64+0x9e/0x1b0

The issue can be triggered as below:

T1 						T2
dm_suspend					table_load
__dm_suspend					dm_setup_md_queue
						dm_mq_init_request_queue
						blk_mq_init_allocated_queue
						=> q->mq_ops = set->ops; (1)
dm_stop_queue / dm_wait_for_completion
=> q->tag_set NULL pointer!	(2)
						=> q->tag_set = set; (3)

Fix this by checking if a valid table (map) exists before performing
request-based suspend and waiting for target I/O. When map is NULL,
skip these table-dependent suspend steps.

Even when map is NULL, no I/O can reach any target because there is
no table loaded; I/O submitted in this state will fail early in the
DM layer. Skipping the table-dependent suspend logic in this case
is safe and avoids NULL pointer dereferences.

Fixes: c4576aed8d85 ("dm: fix request-based dm's use of dm_wait_for_completion")
Cc: stable@vger.kernel.org
Signed-off-by: Zheng Qixing 
Signed-off-by: Mikulas Patocka 
[ omitted DMF_QUEUE_STOPPED flag setting and braces absent in 5.15 ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

dm-integrity: limit MAX_TAG_SIZE to 255

2025-10-29T12:59:45+00:00

[ Upstream commit 77b8e6fbf9848d651f5cb7508f18ad0971f3ffdb ]

MAX_TAG_SIZE was 0x1a8 and it may be truncated in the "bi->metadata_size
= ic->tag_size" assignment. We need to limit it to 255.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Sasha Levin

md/raid1: Fix stack memory use after return in raid1_reshape

2025-07-17T16:25:04+00:00

[ Upstream commit d67ed2ccd2d1dcfda9292c0ea8697a9d0f2f0d98 ]

In the raid1_reshape function, newpool is
allocated on the stack and assigned to conf->r1bio_pool.
This results in conf->r1bio_pool.wait.head pointing
to a stack address.
Accessing this address later can lead to a kernel panic.

Example access path:

raid1_reshape()
{
	// newpool is on the stack
	mempool_t newpool, oldpool;
	// initialize newpool.wait.head to stack address
	mempool_init(&newpool, ...);
	conf->r1bio_pool = newpool;
}

raid1_read_request() or raid1_write_request()
{
	alloc_r1bio()
	{
		mempool_alloc()
		{
			// if pool->alloc fails
			remove_element()
			{
				--pool->curr_nr;
			}
		}
	}
}

mempool_free()
{
	if (pool->curr_nr < pool->min_nr) {
		// pool->wait.head is a stack address
		// wake_up() will try to access this invalid address
		// which leads to a kernel panic
		return;
		wake_up(&pool->wait);
	}
}

Fix:
reinit conf->r1bio_pool.wait after assigning newpool.

Fixes: afeee514ce7f ("md: convert to bioset_init()/mempool_init()")
Signed-off-by: Wang Jinchao 
Reviewed-by: Yu Kuai 
Link: https://lore.kernel.org/linux-raid/20250612112901.3023950-1-wangjinchao600@gmail.com
Signed-off-by: Yu Kuai 
Signed-off-by: Sasha Levin

dm-raid: fix variable in journal device check

2025-07-17T16:24:54+00:00

commit db53805156f1e0aa6d059c0d3f9ac660d4ef3eb4 upstream.

Replace "rdev" with correct loop variable name "r".

Signed-off-by: Heinz Mauelshagen 
Cc: stable@vger.kernel.org
Fixes: 63c32ed4afc2 ("dm raid: add raid4/5/6 journaling support")
Signed-off-by: Mikulas Patocka 
Signed-off-by: Greg Kroah-Hartman

md/md-bitmap: fix dm-raid max_write_behind setting

2025-07-17T16:24:50+00:00

[ Upstream commit 2afe17794cfed5f80295b1b9facd66e6f65e5002 ]

It's supposed to be COUNTER_MAX / 2, not COUNTER_MAX.

Link: https://lore.kernel.org/linux-raid/20250524061320.370630-14-yukuai1@huaweicloud.com
Signed-off-by: Yu Kuai 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Hannes Reinecke 
Signed-off-by: Sasha Levin

dm-mirror: fix a tiny race condition

2025-06-27T10:02:52+00:00

commit 829451beaed6165eb11d7a9fb4e28eb17f489980 upstream.

There's a tiny race condition in dm-mirror. The functions queue_bio and
write_callback grab a spinlock, add a bio to the list, drop the spinlock
and wake up the mirrord thread that processes bios in the list.

It may be possible that the mirrord thread processes the bio just after
spin_unlock_irqrestore is called, before wakeup_mirrord. This spurious
wake-up is normally harmless, however if the device mapper device is
unloaded just after the bio was processed, it may be possible that
wakeup_mirrord(ms) uses invalid "ms" pointer.

Fix this bug by moving wakeup_mirrord inside the spinlock.

Signed-off-by: Mikulas Patocka 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

dm cache: prevent BUG_ON by blocking retries on failed device resumes

2025-06-04T12:32:31+00:00

[ Upstream commit 5da692e2262b8f81993baa9592f57d12c2703dea ]

A cache device failing to resume due to mapping errors should not be
retried, as the failure leaves a partially initialized policy object.
Repeating the resume operation risks triggering BUG_ON when reloading
cache mappings into the incomplete policy object.

Reproduce steps:

1. create a cache metadata consisting of 512 or more cache blocks,
   with some mappings stored in the first array block of the mapping
   array. Here we use cache_restore v1.0 to build the metadata.

cat <> cmeta.xml

  
    
  

EOF
dmsetup create cmeta --table "0 8192 linear /dev/sdc 0"
cache_restore -i cmeta.xml -o /dev/mapper/cmeta --metadata-version=2
dmsetup remove cmeta

2. wipe the second array block of the mapping array to simulate
   data degradations.

mapping_root=$(dd if=/dev/sdc bs=1c count=8 skip=192 \
2>/dev/null | hexdump -e '1/8 "%u\n"')
ablock=$(dd if=/dev/sdc bs=1c count=8 skip=$((4096*mapping_root+2056)) \
2>/dev/null | hexdump -e '1/8 "%u\n"')
dd if=/dev/zero of=/dev/sdc bs=4k count=1 seek=$ablock

3. try bringing up the cache device. The resume is expected to fail
   due to the broken array block.

dmsetup create cmeta --table "0 8192 linear /dev/sdc 0"
dmsetup create cdata --table "0 65536 linear /dev/sdc 8192"
dmsetup create corig --table "0 524288 linear /dev/sdc 262144"
dmsetup create cache --notable
dmsetup load cache --table "0 524288 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0"
dmsetup resume cache

4. try resuming the cache again. An unexpected BUG_ON is triggered
   while loading cache mappings.

dmsetup resume cache

Kernel logs:

(snip)
------------[ cut here ]------------
kernel BUG at drivers/md/dm-cache-policy-smq.c:752!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 332 Comm: dmsetup Not tainted 6.13.4 #3
RIP: 0010:smq_load_mapping+0x3e5/0x570

Fix by disallowing resume operations for devices that failed the
initial attempt.

Signed-off-by: Ming-Hung Tsai 
Signed-off-by: Mikulas Patocka 
Signed-off-by: Sasha Levin

dm: restrict dm device size to 2^63-512 bytes

2025-06-04T12:32:31+00:00

[ Upstream commit 45fc728515c14f53f6205789de5bfd72a95af3b8 ]

The devices with size >= 2^63 bytes can't be used reliably by userspace
because the type off_t is a signed 64-bit integer.

Therefore, we limit the maximum size of a device mapper device to
2^63-512 bytes.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Sasha Levin

dm: fix copying after src array boundaries

2025-06-04T12:32:26+00:00

commit f1aff4bc199cb92c055668caed65505e3b4d2656 upstream.

The blammed commit copied to argv the size of the reallocated argv,
instead of the size of the old_argv, thus reading and copying from
past the old_argv allocated memory.

Following BUG_ON was hit:
[    3.038929][    T1] kernel BUG at lib/string_helpers.c:1040!
[    3.039147][    T1] Internal error: Oops - BUG: 00000000f2000800 [#1]  SMP
...
[    3.056489][    T1] Call trace:
[    3.056591][    T1]  __fortify_panic+0x10/0x18 (P)
[    3.056773][    T1]  dm_split_args+0x20c/0x210
[    3.056942][    T1]  dm_table_add_target+0x13c/0x360
[    3.057132][    T1]  table_load+0x110/0x3ac
[    3.057292][    T1]  dm_ctl_ioctl+0x424/0x56c
[    3.057457][    T1]  __arm64_sys_ioctl+0xa8/0xec
[    3.057634][    T1]  invoke_syscall+0x58/0x10c
[    3.057804][    T1]  el0_svc_common+0xa8/0xdc
[    3.057970][    T1]  do_el0_svc+0x1c/0x28
[    3.058123][    T1]  el0_svc+0x50/0xac
[    3.058266][    T1]  el0t_64_sync_handler+0x60/0xc4
[    3.058452][    T1]  el0t_64_sync+0x1b0/0x1b4
[    3.058620][    T1] Code: f800865e a9bf7bfd 910003fd 941f48aa (d4210000)
[    3.058897][    T1] ---[ end trace 0000000000000000 ]---
[    3.059083][    T1] Kernel panic - not syncing: Oops - BUG: Fatal exception

Fix it by copying the size of src, and not the size of dst, as it was.

Fixes: 5a2a6c428190 ("dm: always update the array size in realloc_argv on success")
Cc: stable@vger.kernel.org
Signed-off-by: Tudor Ambarus 
Signed-off-by: Mikulas Patocka 
Signed-off-by: Greg Kroah-Hartman

dm: always update the array size in realloc_argv on success

2025-06-04T12:32:24+00:00

commit 5a2a6c428190f945c5cbf5791f72dbea83e97f66 upstream.

realloc_argv() was only updating the array size if it was called with
old_argv already allocated. The first time it was called to create an
argv array, it would allocate the array but return the array size as
zero. dm_split_args() would think that it couldn't store any arguments
in the array and would call realloc_argv() again, causing it to
reallocate the initial slots (this time using GPF_KERNEL) and finally
return a size. Aside from being wasteful, this could cause deadlocks on
targets that need to process messages without starting new IO. Instead,
realloc_argv should always update the allocated array size on success.

Fixes: a0651926553c ("dm table: don't copy from a NULL pointer in realloc_argv()")
Cc: stable@vger.kernel.org
Signed-off-by: Benjamin Marzinski 
Signed-off-by: Mikulas Patocka 
Signed-off-by: Greg Kroah-Hartman