CVE-2026-64125: net: bcmgenet: keep RBUF EEE/PM disabled

CVE-2026-64125: net: bcmgenet: keep RBUF EEE/PM disabled

[Greg Kroah-Hartman]

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

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

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

net: bcmgenet: keep RBUF EEE/PM disabled

Setting RBUF_EEE_EN | RBUF_PM_EN in RBUF_ENERGY_CTRL breaks the RX
path on GENET hardware once MAC EEE becomes active. RX traffic stops
flowing while the link stays up and the usual descriptor/RX error
counters remain quiet. In that state the MAC still accepts frames
(rbuf_ovflow_cnt keeps climbing) but RBUF no longer forwards them to
DMA, so rx_packets is no longer incremented at the netdev level. On
some boards the corruption ends up as a paging fault in
skb_release_data via bcmgenet_rx_poll on an LPI exit.

Reproduced on Pi 4B (BCM2711 + BCM54213PE) and confirmed by Florian
Fainelli on an internal Broadcom 4908-family board with the same crash
signature. RBUF_PM_EN is not publicly documented.

This shows up more often now that phy_support_eee() enables EEE by
default, but it also affects older kernels as soon as TX LPI is
turned on via ethtool, so it is not specific to recent changes.

Always clear RBUF_EEE_EN | RBUF_PM_EN in bcmgenet_eee_enable_set so
the bits stay off across resets. UMAC and TBUF setup is left alone so
TX-side EEE keeps working.

The Linux kernel CVE team has assigned CVE-2026-64125 to this issue.


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

	Issue introduced in 3.19 with commit 6ef398ea60d931b97d69ed080bd0bd00fac38ec6 and fixed in 5.10.258 with commit 2040eb83f6ada148fb32dd98b943a498005d79f2
	Issue introduced in 3.19 with commit 6ef398ea60d931b97d69ed080bd0bd00fac38ec6 and fixed in 5.15.209 with commit f2782ddac82c70df313012da5f71f1f06b5553ca
	Issue introduced in 3.19 with commit 6ef398ea60d931b97d69ed080bd0bd00fac38ec6 and fixed in 6.1.175 with commit b579f3a73da7a7e74213558f4cc3d865c30aaa78
	Issue introduced in 3.19 with commit 6ef398ea60d931b97d69ed080bd0bd00fac38ec6 and fixed in 6.6.142 with commit 289499907399c5a9f2ed82cb34df49112bb8488f
	Issue introduced in 3.19 with commit 6ef398ea60d931b97d69ed080bd0bd00fac38ec6 and fixed in 6.12.92 with commit a212fc08f5c48a16a94092bf0a9a8b7cf4483b11
	Issue introduced in 3.19 with commit 6ef398ea60d931b97d69ed080bd0bd00fac38ec6 and fixed in 6.18.34 with commit 3d4ef05266ab16d8ef7dd21658a557801eb78704
	Issue introduced in 3.19 with commit 6ef398ea60d931b97d69ed080bd0bd00fac38ec6 and fixed in 7.0.11 with commit 49bdf6bbb21b9c6e3f4d0c1910bf0ef98424be95
	Issue introduced in 3.19 with commit 6ef398ea60d931b97d69ed080bd0bd00fac38ec6 and fixed in 7.1 with commit 9a1730245e416d11ad5c0f2c100061d61cc43f60

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-2026-64125
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:
	drivers/net/ethernet/broadcom/genet/bcmgenet.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/2040eb83f6ada148fb32dd98b943a498005d79f2
	https://git.kernel.org/stable/c/f2782ddac82c70df313012da5f71f1f06b5553ca
	https://git.kernel.org/stable/c/b579f3a73da7a7e74213558f4cc3d865c30aaa78
	https://git.kernel.org/stable/c/289499907399c5a9f2ed82cb34df49112bb8488f
	https://git.kernel.org/stable/c/a212fc08f5c48a16a94092bf0a9a8b7cf4483b11
	https://git.kernel.org/stable/c/3d4ef05266ab16d8ef7dd21658a557801eb78704
	https://git.kernel.org/stable/c/49bdf6bbb21b9c6e3f4d0c1910bf0ef98424be95
	https://git.kernel.org/stable/c/9a1730245e416d11ad5c0f2c100061d61cc43f60