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CVE-2026-98832

blk-cgroup: save IRQ state in blkg_tryget_closest()

Published 2026-10-18 (today) by the Linux kernel CNA. Subsystem block. Debian urgency: unimportant.

What to do, per Debian release

Debian's own status for CVE-2026-98832 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source

ReleaseStatus VersionWhat this means
Debian 12bookwormnot affected6.1.190-1Nothing to do. bookworm never shipped the vulnerable code.
Debian 13trixienot affected6.12.113-1Nothing to do. trixie never shipped the vulnerable code.
Debian 14forkyfixed7.2.10-1Update the kernel and reboot. Fixed in 7.2.10-1. A running kernel keeps the old code until the machine restarts.
Debian unstablesidfixed7.2.10-1Update the kernel and reboot. Fixed in 7.2.10-1. A running kernel keeps the old code until the machine restarts.

The vulnerability

What the bug is

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.

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

block/blk-cgroup.c

What this is
CONTROL GROUP - BLOCK IO CONTROLLER (BLKIO)MAINTAINERS section matched on block/blk-cgroup.c · cgroups@vger.kernel.org

Check it on the machine

grep -w CONFIG_BLK_CGROUP /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

Show whether Debian builds this, per release

Debian builds this code. Every release below compiles the affected file into the kernels it ships.

  • bookworm, trixie, forky, sidy
y
built into the kernel image on every flavour - only a patch removes it
Build switch
CONFIG_BLK_CGROUP

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published
2026-10-18 (today)source
CVSS
no vector published, unrated
Attack vector
not published
EPSS
not scored
CISA KEV
not listedthe KEV catalogue
Debian urgency
unimportantsource
Subsystem
block

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

IntroducedFixed inCommit
7.27.2.109fcf4317384c
7.27.3327c428ba79b

Why the CNA scored it this way

The kernel CNA published no CVSS vector and no reasoning for CVE-2026-98832, which is why it is shown as unrated rather than given an invented score. 6,405 of the 20,413 CVEs here carry reasoning; this is not one of them.