Information Exposure Affecting kernel-rt-debug-modules-extra package, versions *

Note: Versions mentioned in the description apply only to the upstream kernel-rt-debug-modules-extra package and not the kernel-rt-debug-modules-extra package as distributed by Centos. See How to fix? for Centos:8 relevant fixed versions and status.

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

net: stmmac: Disable Tx queues when reconfiguring the interface

The Tx queues were not disabled in situations where the driver needed to stop the interface to apply a new configuration. This could result in a kernel panic when doing any of the 3 following actions:

• reconfiguring the number of queues (ethtool -L)
• reconfiguring the size of the ring buffers (ethtool -G)
• installing/removing an XDP program (ip l set dev ethX xdp)

Prevent the panic by making sure netif_tx_disable is called when stopping an interface.

Without this patch, the following kernel panic can be observed when doing any of the actions above:

Unable to handle kernel paging request at virtual address ffff80001238d040 [....] Call trace: dwmac4_set_addr+0x8/0x10 dev_hard_start_xmit+0xe4/0x1ac sch_direct_xmit+0xe8/0x39c __dev_queue_xmit+0x3ec/0xaf0 dev_queue_xmit+0x14/0x20 [...] [ end trace 0000000000000002 ]---

• https://access.redhat.com/security/cve/CVE-2021-47558
• https://git.kernel.org/stable/c/a92f0eebb8dc008b9e8c51c6f7b8c93b27a29a43
• https://git.kernel.org/stable/c/b270bfe697367776eca2e6759a71d700fb8d82a2