CVE-2025-40146: blk-mq: fix potential deadlock while nr_requests grown

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-11-12 · updated 2026-10-19

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/

Affected products

Linux kernel: 3.16 — fixed in 6.18

How to fix

Upgrade to a fixed version: Linux kernel 6.18. Check the vendor advisory for mitigations.

References

https://git.kernel.org/stable/c/8d26acf8477174d8ef690eb6affe13a630f586ae
https://git.kernel.org/stable/c/b86433721f46d934940528f28d49c1dedb690df1

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