CVE-2025-37932

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

sch_htb: make htb_qlen_notify() idempotent

htb_qlen_notify() always deactivates the HTB class and in fact could trigger a warning if it is already deactivated. Therefore, it is not idempotent and not friendly to its callers, like fq_codel_dequeue().

Let's make it idempotent to ease qdisc_tree_reduce_backlog() callers' life.

htb_qlen_notify() could wrongly trigger a kernel warning when called on an already-deactivated HTB class. This patch adds a guard to make the function idempotent. The security impact is minimal.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.