CVE-2026-53326

What the bug is

When booting a debug PREEMPT_RT kernel on an ARM64 system, a "inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage" lockdep warning message was reported to the console. During early boot, interrupts are enabled before the scheduler is enabled. In this window (before SYSTEM_SCHEDULING is set) interrupts can fire and in the hard interrupt context handler attempt to fill the pool This can lead to a deadlock when the interrupt occurred when the interrupt hits a region which holds a lock that is required to be taken in the allocation path. Add a new can_fill_pool() helper and reorder the exception rule and forbid this scenario by excluding allocations from hard interrupt context.

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.

lib/debugobjects.c

What this is

DEBUGOBJECTS:MAINTAINERS section matched on lib/debugobjects.c · linux-kernel@vger.kernel.org · Maintained

Kernel module

none to look for. The file would have gone into debugobjects, and Debian does not compile it into that module, so finding debugobjects in lsmod would say nothing about this CVE.

Check it on the machine

grep -w CONFIG_DEBUG_OBJECTS /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 does not build this code. In 4 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.

• bookworm, trixie, forky, sidn

n

not enabled on any flavour - this release does not build the code

Build switch

CONFIG_DEBUG_OBJECTS

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

2026-07-01 (4 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.10%, higher than 0.8% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

unimportantsource

Subsystem

lib

Upstream fixes

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

Introduced	Fixed in	Commit
6.1.177	6.1.177	3cc90ea0dd0f
6.6.144	6.6.144	5d95f6b267f3
6.12.95	6.12.95	27335c500141
6.18.37	6.18.37	44b8b03a9fb5
6.19	7.0.13	7bc71bdb1c15
6.19	7.1	0d046ae10625