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.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
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.
Sources
Also known as DEBIAN-CVE-2026-98832, GHSA-9gxg-wj69-fwm2, UBUNTU-CVE-2026-98832.