Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
sch_hfsc: make hfsc_qlen_notify() idempotent
hfsc_qlen_notify() is not idempotent either and not friendly to its callers, like fq_codel_dequeue(). Let’s make it idempotent to ease qdisc_tree_reduce_backlog() callers’ life:
-
update_vf() decreases cl->cl_nactive, so we can check whether it is non-zero before calling it.
-
eltree_remove() always removes RB node cl->el_node, but we can use RB_EMPTY_NODE() + RB_CLEAR_NODE() to make it safe.
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 7 ELS , Oracle Linux 6 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- kernel @ 2.6.32 (+15 more)
In the Linux kernel, the following vulnerability has been resolved:
sch_hfsc: make hfsc_qlen_notify() idempotent
hfsc_qlen_notify() is not idempotent either and not friendly to its callers, like fq_codel_dequeue(). Let’s make it idempotent to ease qdisc_tree_reduce_backlog() callers’ life:
-
update_vf() decreases cl->cl_nactive, so we can check whether it is non-zero before calling it.
-
eltree_remove() always removes RB node cl->el_node, but we can use RB_EMPTY_NODE() + RB_CLEAR_NODE() to make it safe.