dm-io: clone the source bio instead of copying its biovec
Summary
| CVE | CVE-2026-89578 |
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-11 20:19:42 UTC |
| Updated | 2026-09-11 20:19:42 UTC |
| Description | In the Linux kernel, the following vulnerability has been resolved:
dm-io: clone the source bio instead of copying its biovec
For DM_IO_BIO requests, do_region() built each destination bio by walking
the source bio's biovec and re-adding the pages one at a time, tracking
the remaining transfer in sectors. The vector lengths are byte granular
and need not be sector aligned (e.g. a misaligned O_DIRECT buffer split
across pages), so the sector-based accounting could lose a sub-sector
fragment: to_sector() truncated the remainder and the outer loop spun
forever submitting empty bios, hanging the I/O.
There is no need to rebuild the biovec at all. The destination reads into
(or writes from) exactly the same pages as the source bio, so the bio can
simply clone the source's biovec with bio_alloc_clone() and remap it to
the target device. The clone inherits the source's iterator and alignment,
and the block layer splits it to the target's limits on submission, so the
whole region maps to a single cloned bio with no manual page copying or
sector accounting.
This removes the per-page copy path (and its open-coded bvec dpages
helpers) for bio-backed I/O and fixes the hang on misaligned direct I/O to
a dm-mirror device. Page-list, vma and kmem sources keep the existing copy
path. |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|
| CNA |
Linux |
Linux |
affected 5ff3f74e145adc79b49668adb8de276446acf6be 9493ac67623d45b7d4671d2b0b4d0633c2bc2e51 git |
Not specified |
| CNA |
Linux |
Linux |
affected 5ff3f74e145adc79b49668adb8de276446acf6be 8dc48b68d7c3e6ecaae80fc1592befb0e8603d6c git |
Not specified |
| CNA |
Linux |
Linux |
affected 5ff3f74e145adc79b49668adb8de276446acf6be 62dc37a819a5a5de5cba989ad9e96ee214b9253e git |
Not specified |
| CNA |
Linux |
Linux |
affected 6.18 |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.18 semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.18.50 6.18.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.2.4 7.2.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.3-rc1 * original_commit_for_fix |
Not specified |
References
| Reference | Source | Link | Tags |
|---|
| git.kernel.org/stable/c/9493ac67623d45b7d4671d2b0b4d0633c2bc2e51 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/62dc37a819a5a5de5cba989ad9e96ee214b9253e |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/8dc48b68d7c3e6ecaae80fc1592befb0e8603d6c |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| CVE Program record |
CVE.ORG |
www.cve.org |
canonical |
| NVD vulnerability detail |
NVD |
nvd.nist.gov |
canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.