CVE-2026-53319

What the bug is

wbt_init_enable_default() uses WARN_ON_ONCE to check for failures from wbt_alloc() and wbt_init(). However, both are expected failure paths: - wbt_alloc() can return NULL under memory pressure (-ENOMEM) - wbt_init() can fail with -EBUSY if wbt is already registered syzbot triggers this by injecting memory allocation failures during MTD partition creation via ioctl(BLKPG), causing a spurious warning. wbt_init_enable_default() is a best-effort initialization called from blk_register_queue() with a void return type. Failure simply means the disk operates without writeback throttling, which is harmless. Replace WARN_ON_ONCE with plain if-checks, consistent with how wbt_set_lat() in the same file already handles these failures. Add a pr_warn() for the wbt_init() failure to retain diagnostic information without triggering a full stack trace.

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-wbt.c

What this is

BLOCK LAYERMAINTAINERS section matched on block/ · linux-block@vger.kernel.org · Maintained

Check it on the machine

grep -w CONFIG_BLK_WBT /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_WBT

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

2026-06-26 (4 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.14%, higher than 3.2% of all CVEssource

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

Introduced	Fixed in	Commit
7.0	7.0.10	fd7a98265707
7.0	7.1	e9b004ff8306