net: bcmgenet: fix NULL dereference in set_coalesce before first open
The Rx ring priv and index are only set in bcmgenet_init_rx_ring(),
which runs at open. Setting the Rx coalescing parameters on an interface
that was never opened, e.g. "ethtool -C eth0 rx-usecs 50", dereferences
a NULL ring->priv. The oops happens with RTNL held, so networking
stays stuck until a reboot:
Unable to handle kernel paging request at virtual address 0000000000002788
pc : bcmgenet_set_rx_coalesce.isra.0+0x10/0x88
lr : bcmgenet_set_coalesce+0xe8/0x180
Call trace:
bcmgenet_set_rx_coalesce.isra.0+0x10/0x88 (P)
__ethnl_set_coalesce.isra.0+0x490/0x570
ethnl_set_coalesce+0x48/0xc0
ethnl_default_set_doit+0xf4/0x230
genl_family_rcv_msg_doit+0xe8/0x160
genl_rcv_msg+0x220/0x2a0
netlink_rcv_skb+0x68/0x140
genl_rcv+0x40/0x60
netlink_unicast+0x338/0x3c0
netlink_sendmsg+0x19c/0x3f8
__sock_sendmsg+0x64/0xc0
__sys_sendto+0x124/0x198
__arm64_sys_sendto+0x30/0x48
Set priv and index at probe. Writing the registers while the interface
is down is harmless because open resets the MAC and
bcmgenet_init_rx_coalesce() reapplies the stored values.
It was observed on a Raspberry Pi CM4, but should apply to all other
genet devices.
Analysis
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Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No data.
No data.
No data available yet.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
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Sun, 18 Oct 2026 16:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: net: bcmgenet: fix NULL dereference in set_coalesce before first open The Rx ring priv and index are only set in bcmgenet_init_rx_ring(), which runs at open. Setting the Rx coalescing parameters on an interface that was never opened, e.g. "ethtool -C eth0 rx-usecs 50", dereferences a NULL ring->priv. The oops happens with RTNL held, so networking stays stuck until a reboot: Unable to handle kernel paging request at virtual address 0000000000002788 pc : bcmgenet_set_rx_coalesce.isra.0+0x10/0x88 lr : bcmgenet_set_coalesce+0xe8/0x180 Call trace: bcmgenet_set_rx_coalesce.isra.0+0x10/0x88 (P) __ethnl_set_coalesce.isra.0+0x490/0x570 ethnl_set_coalesce+0x48/0xc0 ethnl_default_set_doit+0xf4/0x230 genl_family_rcv_msg_doit+0xe8/0x160 genl_rcv_msg+0x220/0x2a0 netlink_rcv_skb+0x68/0x140 genl_rcv+0x40/0x60 netlink_unicast+0x338/0x3c0 netlink_sendmsg+0x19c/0x3f8 __sock_sendmsg+0x64/0xc0 __sys_sendto+0x124/0x198 __arm64_sys_sendto+0x30/0x48 Set priv and index at probe. Writing the registers while the interface is down is harmless because open resets the MAC and bcmgenet_init_rx_coalesce() reapplies the stored values. It was observed on a Raspberry Pi CM4, but should apply to all other genet devices. | |
| Title | net: bcmgenet: fix NULL dereference in set_coalesce before first open | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-18T15:48:43.367Z
Reserved: 2026-09-25T10:25:14.370Z
Link: CVE-2026-98798
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-18T16:17:33.807
Modified: 2026-10-18T16:17:33.807
Link: CVE-2026-98798
Redhat
No data.
OpenCVE Enrichment
No data.
No weakness.