In the Linux kernel, the following vulnerability has been resolved:
dm cache: prevent BUG_ON by blocking retries on failed device resumes
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 <<EOF >> cmeta.xml
<superblock uuid="" block_size="128" nr_cache_blocks="512" \
policy="smq" hint_width="4">
<mappings>
<mapping cache_block="0" origin_block="0" dirty="false"/>
</mappings>
</superblock>
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.
References
Configurations
Configuration 1 (hide)
|
Configuration 2 (hide)
|
History
17 Dec 2025, 19:18
| Type | Values Removed | Values Added |
|---|---|---|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
| References | () https://git.kernel.org/stable/c/00586b78eeb7c626a14ca13453a1631f88a7cf36 - Patch | |
| References | () https://git.kernel.org/stable/c/025c8f477625eb39006ded650e7d027bcfb20e79 - Patch | |
| References | () https://git.kernel.org/stable/c/3986ef4a9b6a0d9c28bc325d8713beba5e67586f - Patch | |
| References | () https://git.kernel.org/stable/c/5da692e2262b8f81993baa9592f57d12c2703dea - Patch | |
| References | () https://git.kernel.org/stable/c/c5356a5e80442131e2714d0d26bb110590e4e568 - Patch | |
| References | () https://git.kernel.org/stable/c/c614584c2a66b538f469089ac089457a34590c14 - Patch | |
| References | () https://git.kernel.org/stable/c/cc80a5cc520939d0a7d071cc4ae4b3c55ef171d0 - Patch | |
| References | () https://git.kernel.org/stable/c/f3128e3074e8af565cc6a66fe3384a56df87f803 - Patch | |
| References | () https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html - Third Party Advisory | |
| References | () https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html - Third Party Advisory | |
| CWE | CWE-617 | |
| CPE | cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
|
| First Time |
Linux
Debian Debian debian Linux Linux linux Kernel |
03 Nov 2025, 18:16
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
|
| Summary |
|
18 Jun 2025, 10:15
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2025-06-18 10:15
Updated : 2025-12-17 19:18
NVD link : CVE-2025-38066
Mitre link : CVE-2025-38066
CVE.ORG link : CVE-2025-38066
JSON object : View
Products Affected
debian
- debian_linux
linux
- linux_kernel
CWE
CWE-617
Reachable Assertion
