# CVE-2026-98832: blk-cgroup: save IRQ state in blkg_tryget_closest()

> A race condition in the Linux kernel block cgroup subsystem can cause a deadlock and system hang when interrupts are improperly enabled during nested lock acquisition.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-98832, GHSA-9gxg-wj69-fwm2, UBUNTU-CVE-2026-98832

## What is CVE-2026-98832?

CVE-2026-98832 is a vulnerability in Linux, published on 18 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

blk-cgroup: save IRQ state in blkg_tryget_closest()

bio_set_dev() associates the bio with a blkg through bio_associate_blkg().
If the blkg lookup misses, blkg_tryget_closest() takes q->queue_lock with
spin_lock_irq() and releases it with spin_unlock_irq(), which
unconditionally enables local interrupts.

Callers may call bio_set_dev() with interrupts already disabled, e.g.
dm-thin's pool_map() does so while holding pool->lock taken with
spin_lock_irq().  The nested spin_unlock_irq() then enables interrupts
while pool->lock is still held, so an I/O completion softirq can run on
the same CPU, re-acquire pool->lock (thin_endio(), or overwrite_endio()
-> complete_mapping_preparation()) and deadlock.  lockdep reports this
as inconsistent SOFTIRQ-ON-W to IN-SOFTIRQ-W usage.

Commit 3a762de55b4e ("block: save irq state in blkg_lookup_create()")
fixed the same problem while the lock lived in blkg_lookup_create(), but
commit 9327a865e395 ("blk-cgroup: don't nest queue_lock under rcu in
blkg_lookup_create()") moved the locking into blkg_tryget_closest() and
reverted it to spin_lock_irq().

Save and restore the caller's IRQ state instead.

## Which versions are affected by CVE-2026-98832?


## How do I fix CVE-2026-98832?

Apply the vendor's patch.

## Is CVE-2026-98832 being exploited?

There is no known exploitation of CVE-2026-98832 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98832 and fix it if it is affected.

What it is: CVE-2026-98832 is a vulnerability in Linux, published on 18 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-98832 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-98832/ (Markdown: https://insights.sbomify.com/CVE-2026-98832/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98832
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98832
- OSV: https://osv.dev/vulnerability/CVE-2026-98832

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98832/
Summaries are generated and may contain mistakes; the official description above is the record.