linux-cve-announce - CVE-2025-40146: blk-mq: fix potential deadlock while nr

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Message-ID: <2025111256-CVE-2025-40146-b919@gregkh>
Date: Wed, 12 Nov 2025 19:24:22 +0900
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-40146: blk-mq: fix potential deadlock while nr_requests grown

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

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

blk-mq: fix potential deadlock while nr_requests grown

Allocate and free sched_tags while queue is freezed can deadlock[1],
this is a long term problem, hence allocate memory before freezing
queue and free memory after queue is unfreezed.

[1] https://lore.kernel.org/all/0659ea8d-a463-47c8-9180-43c719e106eb@linux.ibm.com/

The Linux kernel CVE team has assigned CVE-2025-40146 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 3.16 with commit e3a2b3f931f59d5284abd13faf8bded726884ffd and fixed in 6.17.3 with commit 8d26acf8477174d8ef690eb6affe13a630f586ae
	Issue introduced in 3.16 with commit e3a2b3f931f59d5284abd13faf8bded726884ffd and fixed in 6.18-rc1 with commit b86433721f46d934940528f28d49c1dedb690df1

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-40146
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	block/blk-mq.c
	block/blk-mq.h
	block/blk-sysfs.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/8d26acf8477174d8ef690eb6affe13a630f586ae
	https://git.kernel.org/stable/c/b86433721f46d934940528f28d49c1dedb690df1