Skip to content
OpenAdvisories
Medium · 5.5 CVE-2024-55916 EUVD-2024-52846GHSA-r35m-8jf8-g83g

Drivers: hv: util: Avoid accessing a ringbuffer not initialized yet

Published Jan 11, 2025 · Updated May 11, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: kernel Package: linux Package: linux Package: linux-allwinner-5.19 Package: linux-aws Package: linux-aws-5.0 Package: linux-aws-5.11 Package: linux-aws-5.13 Package: linux-aws-5.15 Package: linux-aws-5.19 Package: linux-aws-5.3 Package: linux-aws-5.4 Package: linux-aws-5.8 Package: linux-aws-6.2 Package: linux-aws-6.5 Package: linux-aws-6.8 Package: linux-aws-fips Package: linux-aws-hwe Package: linux-azure Package: linux-azure-4.15 Package: linux-azure-5.11 Package: linux-azure-5.13 Package: linux-azure-5.15 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.4 Package: linux-azure-5.8 Package: linux-azure-6.11 Package: linux-azure-6.2 Package: linux-azure-6.5 Package: linux-azure-6.8 Package: linux-azure-edge Package: linux-azure-fde Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.2 Package: linux-azure-fips Package: linux-azure-nvidia Package: linux-bluefield Package: linux-fips Package: linux-gcp Package: linux-gcp-4.15 Package: linux-gcp-5.11 Package: linux-gcp-5.13 Package: linux-gcp-5.15 Package: linux-gcp-5.19 Package: linux-gcp-5.3 Package: linux-gcp-5.4 Package: linux-gcp-5.8 Package: linux-gcp-6.11 Package: linux-gcp-6.2 Package: linux-gcp-6.5 Package: linux-gcp-6.8 Package: linux-gcp-fips Package: linux-gke Package: linux-gke-4.15 Package: linux-gke-5.15 Package: linux-gke-5.4 Package: linux-gkeop Package: linux-gkeop-5.15 Package: linux-gkeop-5.4 Package: linux-hwe Package: linux-hwe-5.11 Package: linux-hwe-5.13 Package: linux-hwe-5.15 Package: linux-hwe-5.19 Package: linux-hwe-5.4 Package: linux-hwe-5.8 Package: linux-hwe-6.11 Package: linux-hwe-6.2 Package: linux-hwe-6.5 Package: linux-hwe-6.8 Package: linux-hwe-edge Package: linux-ibm Package: linux-ibm-5.15 Package: linux-ibm-5.4 Package: linux-ibm-6.8 Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-intel-iotg Package: linux-intel-iotg-5.15 Package: linux-iot Package: linux-kvm Package: linux-lowlatency Package: linux-lowlatency-hwe-5.15 Package: linux-lowlatency-hwe-5.19 Package: linux-lowlatency-hwe-6.2 Package: linux-lowlatency-hwe-6.5 Package: linux-lowlatency-hwe-6.8 Package: linux-lts-xenial Package: linux-nvidia Package: linux-nvidia-6.11 Package: linux-nvidia-6.2 Package: linux-nvidia-6.5 Package: linux-nvidia-6.8 Package: linux-nvidia-lowlatency Package: linux-nvidia-tegra Package: linux-nvidia-tegra-5.15 Package: linux-nvidia-tegra-igx Package: linux-oem Package: linux-oem-5.10 Package: linux-oem-5.13 Package: linux-oem-5.14 Package: linux-oem-5.17 Package: linux-oem-5.6 Package: linux-oem-6.0 Package: linux-oem-6.1 Package: linux-oem-6.11 Package: linux-oem-6.5 Package: linux-oem-6.8 Package: linux-oracle Package: linux-oracle-5.0 Package: linux-oracle-5.11 Package: linux-oracle-5.13 Package: linux-oracle-5.15 Package: linux-oracle-5.3 Package: linux-oracle-5.4 Package: linux-oracle-5.8 Package: linux-oracle-6.5 Package: linux-oracle-6.8 Package: linux-raspi Package: linux-raspi-5.4 Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-realtime-6.8 Package: linux-riscv Package: linux-riscv-5.11 Package: linux-riscv-5.15 Package: linux-riscv-5.19 Package: linux-riscv-5.8 Package: linux-riscv-6.5 Package: linux-riscv-6.8 Package: linux-starfive-5.19 Package: linux-starfive-6.2 Package: linux-starfive-6.5 Package: linux-vmware Package: linux-xilinx Package: linux-xilinx-zynqmp Platform: Linux Ecosystem: Azure Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

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

Drivers: hv: util: Avoid accessing a ringbuffer not initialized yet

If the KVP (or VSS) daemon starts before the VMBus channel's ringbuffer is
fully initialized, we can hit the panic below:

hv_utils: Registering HyperV Utility Driver
hv_vmbus: registering driver hv_utils
...
BUG: kernel NULL pointer dereference, address: 0000000000000000
CPU: 44 UID: 0 PID: 2552 Comm: hv_kvp_daemon Tainted: G E 6.11.0-rc3+ #1
RIP: 0010:hv_pkt_iter_first+0x12/0xd0
Call Trace:
...
vmbus_recvpacket
hv_kvp_onchannelcallback
vmbus_on_event
tasklet_action_common
tasklet_action
handle_softirqs
irq_exit_rcu
sysvec_hyperv_stimer0
</IRQ>
<TASK>
asm_sysvec_hyperv_stimer0
...
kvp_register_done
hvt_op_read
vfs_read
ksys_read
__x64_sys_read

This can happen because the KVP/VSS channel callback can be invoked
even before the channel is fully opened:
1) as soon as hv_kvp_init() -> hvutil_transport_init() creates
/dev/vmbus/hv_kvp, the kvp daemon can open the device file immediately and
register itself to the driver by writing a message KVP_OP_REGISTER1 to the
file (which is handled by kvp_on_msg() ->kvp_handle_handshake()) and
reading the file for the driver's response, which is handled by
hvt_op_read(), which calls hvt->on_read(), i.e. kvp_register_done().

2) the problem with kvp_register_done() is that it can cause the
channel callback to be called even before the channel is fully opened,
and when the channel callback is starting to run, util_probe()->
vmbus_open() may have not initialized the ringbuffer yet, so the
callback can hit the panic of NULL pointer dereference.

To reproduce the panic consistently, we can add a "ssleep(10)" for KVP in
__vmbus_open(), just before the first hv_ringbuffer_init(), and then we
unload and reload the driver hv_utils, and run the daemon manually within
the 10 seconds.

Fix the panic by reordering the steps in util_probe() so the char dev
entry used by the KVP or VSS daemon is not created until after
vmbus_open() has completed. This reordering prevents the race condition
from happening.

Affected products

VendorProductAffectedFixed
Linux Linux 4.9 5.4.289

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 linux 6.12.8-1 —
Debian 13 linux 6.12.8-1 —
Debian 12 linux 6.1.123-1 —
Debian 11 linux 5.10.234-1 DLA-4075-1
Debian 11 linux-6.1 6.1.128-1~deb11u1 DLA-4076-1
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 22.04 LTS linux-bluefield 5.15.0-1062.64 —
Ubuntu 24.04 LTS linux 6.8.0-60.63 USN-7513-1
Ubuntu 24.04 LTS linux-aws 6.8.0-1029.31 USN-7513-1
Ubuntu 24.04 LTS linux-azure 6.8.0-1029.34 USN-7513-3
Ubuntu 24.04 LTS linux-azure-6.11 6.11.0-1012.12~24.04.1 —
Ubuntu 24.04 LTS linux-azure-nvidia 6.8.0-1016.17 USN-7522-1
Ubuntu 24.04 LTS linux-gcp 6.8.0-1030.32 USN-7515-2
Ubuntu 24.04 LTS linux-gcp-6.11 6.11.0-1011.11~24.04.1 —
Ubuntu 24.04 LTS linux-gke 6.8.0-1025.29 USN-7515-1
Ubuntu 24.04 LTS linux-gkeop 6.8.0-1012.14 USN-7515-2
Ubuntu 24.04 LTS linux-hwe-6.11 6.11.0-21.21~24.04.1 USN-7379-1
Ubuntu 24.04 LTS linux-ibm 6.8.0-1026.26 USN-7513-1
Ubuntu 24.04 LTS linux-lowlatency-hwe-6.11 6.11.0-1011.12~24.04.1 USN-7381-1
Ubuntu 24.04 LTS linux-nvidia 6.8.0-1028.31 USN-7514-1
Ubuntu 24.04 LTS linux-nvidia-6.11 6.11.0-1007.7 —
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1028.31.1 USN-7514-1
Ubuntu 24.04 LTS linux-nvidia-tegra 6.8.0-1008.8 —
Ubuntu 24.04 LTS linux-oem-6.11 6.11.0-1017.17 USN-7382-1
Ubuntu 24.04 LTS linux-oem-6.8 6.8.0-1028.28 USN-7513-3
Ubuntu 24.04 LTS linux-oracle 6.8.0-1026.27 USN-7513-1
Ubuntu 24.04 LTS linux-raspi 6.8.0-1028.32 USN-7524-1
Ubuntu 24.04 LTS linux-realtime +1 No fix yet —
Ubuntu 24.04 LTS linux-riscv +1 6.8.0-60.63.1 USN-7513-1
Ubuntu 24.04 LTS linux-xilinx 6.8.0-1017.18 —
Ubuntu 22.04 LTS linux +1 5.15.0-135.146 USN-7387-1
Ubuntu 22.04 LTS linux-aws 5.15.0-1080.87 USN-7387-1
Ubuntu 22.04 LTS linux-aws-6.8 6.8.0-1029.31~22.04.1 USN-7513-1
Ubuntu 22.04 LTS linux-azure 5.15.0-1084.93 USN-7387-1
Ubuntu 22.04 LTS linux-azure-6.8 6.8.0-1029.34~22.04.1 USN-7513-3
Ubuntu 22.04 LTS linux-azure-fde 5.15.0-1084.93.1 —
Ubuntu 22.04 LTS linux-gcp 5.15.0-1079.88 USN-7387-1
Ubuntu 22.04 LTS linux-gcp-6.8 6.8.0-1030.32~22.04.1 USN-7515-2
Ubuntu 22.04 LTS linux-gke +1 5.15.0-1077.83 USN-7387-1
Ubuntu 22.04 LTS linux-gkeop 5.15.0-1062.70 USN-7387-1
Ubuntu 22.04 LTS linux-hwe-6.8 6.8.0-60.63~22.04.1 USN-7513-4
Ubuntu 22.04 LTS linux-ibm 5.15.0-1072.75 USN-7387-1
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1026.26~22.04.1 —
Ubuntu 22.04 LTS linux-intel-iot-realtime 5.15.0-1073.75 —
Ubuntu 22.04 LTS linux-intel-iotg 5.15.0-1075.81 USN-7387-1
Ubuntu 22.04 LTS linux-kvm 5.15.0-1076.81 USN-7388-1
Ubuntu 22.04 LTS linux-lowlatency-hwe-6.8 6.8.0-60.63.1~22.04.1 USN-7513-1
Ubuntu 22.04 LTS linux-nvidia 5.15.0-1074.75 USN-7387-1
Ubuntu 22.04 LTS linux-nvidia-6.8 6.8.0-1028.31~22.04.1 USN-7514-1
Ubuntu 22.04 LTS linux-nvidia-tegra 5.15.0-1033.33 USN-7389-1
Ubuntu 22.04 LTS linux-nvidia-tegra-igx 5.15.0-1021.21 USN-7389-1
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1026.27~22.04.1 USN-7513-5
Ubuntu 22.04 LTS linux-raspi 5.15.0-1074.77 USN-7387-1
Ubuntu 22.04 LTS linux-riscv +31 No fix yet —
Ubuntu 22.04 LTS linux-riscv-6.8 6.8.0-62.65~22.04.1 —
Ubuntu 22.04 LTS linux-xilinx-zynqmp 5.15.0-1044.48 USN-7390-1
Ubuntu 20.04 LTS linux 5.4.0-211.231 USN-7391-1
Ubuntu 20.04 LTS linux-aws 5.4.0-1142.152 USN-7392-3
Ubuntu 20.04 LTS linux-aws-5.15 5.15.0-1080.87~20.04.1 USN-7388-1
Ubuntu 20.04 LTS linux-azure 5.4.0-1147.154 USN-7392-1
Ubuntu 20.04 LTS linux-azure-5.15 5.15.0-1086.95~20.04.1 USN-7421-1
Ubuntu 20.04 LTS linux-azure-fde-5.15 5.15.0-1086.95~20.04.1.1 USN-7421-1
Ubuntu 20.04 LTS linux-bluefield 5.4.0-1101.108 USN-7392-1
Ubuntu 20.04 LTS linux-gcp 5.4.0-1145.154 USN-7392-1
Ubuntu 20.04 LTS linux-gcp-5.15 5.15.0-1081.90~20.04.1 USN-7459-2
Ubuntu 20.04 LTS linux-gke +28 No fix yet —
Ubuntu 20.04 LTS linux-hwe-5.15 5.15.0-136.147~20.04.1 USN-7407-1
Ubuntu 20.04 LTS linux-ibm 5.4.0-1088.93 USN-7392-1
Ubuntu 20.04 LTS linux-ibm-5.15 5.15.0-1074.77~20.04.1 USN-7458-1
Ubuntu 20.04 LTS linux-iot 5.4.0-1048.51 USN-7413-1
Ubuntu 20.04 LTS linux-kvm 5.4.0-1129.138 USN-7392-1
Ubuntu 20.04 LTS linux-lowlatency-hwe-5.15 5.15.0-135.146~20.04.1 USN-7387-1
Ubuntu 20.04 LTS linux-oracle 5.4.0-1140.150 USN-7392-1
Ubuntu 20.04 LTS linux-oracle-5.15 +1 5.15.0-1077.83~20.04.1 USN-7459-1, USN-7387-1
Ubuntu 20.04 LTS linux-raspi 5.4.0-1129.142 USN-7539-1
Ubuntu 20.04 LTS linux-riscv-5.15 5.15.0-1075.79~20.04.1 —
Ubuntu 20.04 LTS linux-xilinx-zynqmp 5.4.0-1060.64 USN-7392-1
Ubuntu 18.04 LTS linux-gcp +14 No fix yet —
Show 16 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 16.04 LTS linux-hwe-edge No fix yet —
Ubuntu Pro Realtime 24.04 LTS linux-raspi-realtime 6.8.0-2023.24 USN-7523-1
Ubuntu Pro Realtime 24.04 LTS linux-realtime 6.8.1-1022.23 USN-7513-2
Ubuntu Pro Realtime 22.04 LTS linux-intel-iot-realtime 5.15.0-1073.75 USN-7387-3
Ubuntu Pro Realtime 22.04 LTS linux-realtime 5.15.0-1080.88 USN-7387-3
Ubuntu Pro Realtime 22.04 LTS linux-realtime-6.8 6.8.1-1022.23~22.04.1 —
Ubuntu Pro FIPS 20.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS 16.04 LTS linux-fips No fix yet —
Ubuntu Pro FIPS-updates 24.04 LTS linux-fips 6.8.0-78.78+fips1 —
Ubuntu Pro FIPS-updates 22.04 LTS linux-aws-fips 5.15.0-1080.87+fips1 USN-7387-2
Ubuntu Pro FIPS-updates 22.04 LTS linux-azure-fips 5.15.0-1083.92+fips1 USN-7387-2
Ubuntu Pro FIPS-updates 22.04 LTS linux-fips 5.15.0-135.146+fips1 USN-7387-2
Ubuntu Pro FIPS-updates 22.04 LTS linux-gcp-fips 5.15.0-1079.88+fips1 USN-7387-2
Ubuntu Pro FIPS-updates 20.04 LTS linux-aws-fips 5.4.0-1142.153+fips1 USN-7392-4
Ubuntu Pro FIPS-updates 20.04 LTS linux-azure-fips 5.4.0-1147.154+fips1 USN-7392-2
Ubuntu Pro FIPS-updates 20.04 LTS linux-fips 5.4.0-1116.126 USN-7393-1
Ubuntu Pro FIPS-updates 20.04 LTS linux-gcp-fips 5.4.0-1145.154+fips1 USN-7392-2
Ubuntu Pro FIPS-updates 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-updates 16.04 LTS linux-fips No fix yet —
Ubuntu Pro FIPS-preview 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro 20.04 LTS linux-nvidia-tegra-5.15 5.15.0-1039.39~20.04.1 —
Ubuntu Pro 18.04 LTS linux +5 No fix yet —
Ubuntu Pro 18.04 LTS linux-aws-5.4 5.4.0-1142.152~18.04.1 USN-7401-1
Ubuntu Pro 18.04 LTS linux-azure-5.4 5.4.0-1147.154~18.04.1 USN-7392-1
Ubuntu Pro 18.04 LTS linux-gcp-5.4 5.4.0-1145.154~18.04.1 USN-7392-1
Ubuntu Pro 18.04 LTS linux-hwe-5.4 5.4.0-211.231~18.04.1 USN-7391-1
Ubuntu Pro 18.04 LTS linux-ibm-5.4 5.4.0-1090.95~18.04.1 USN-7463-1
Ubuntu Pro 18.04 LTS linux-oracle-5.4 5.4.0-1140.149~18.04.1 USN-7392-1
Ubuntu Pro 18.04 LTS linux-raspi-5.4 5.4.0-1129.142~18.04.1 USN-7540-1
Ubuntu Pro 16.04 LTS linux +7 No fix yet —
Ubuntu Pro 14.04 LTS linux-aws +2 No fix yet —
ReleasePackageFixed inAdvisory
SLES 15 SP6 kernel-64kb +6 6.4.0-150600.23.38.1 SUSE-SU-2025:0499-1
SLES 15 SP6 kernel-azure +2 6.4.0-150600.8.26.1 SUSE-SU-2025:0428-1
SLES 15 SP6 kernel-coco +3 6.4.0-15061.12.coco15sp6.1 SUSE-SU-2025:0289-1
SLES 15 SP6 kernel-default-base 6.4.0-150600.23.38.1.150600.12.16.2 SUSE-SU-2025:0499-1
SLES 15 SP5 kernel-64kb +6 5.14.21-150500.55.94.1 SUSE-SU-2025:0577-2, SUSE-SU-2025:0577-1
SLES 15 SP5 kernel-default-base 5.14.21-150500.55.94.1.150500.6.43.1 SUSE-SU-2025:0577-2, SUSE-SU-2025:0577-1
SLES 12 SP5 kernel-syms +2 4.12.14-122.247.1 SUSE-SU-2025:0565-1
Show 9 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 15 SP5 kernel-default-base 5.14.21-150500.55.94.1.150500.6.43.1 SUSE-SU-2025:0577-2, SUSE-SU-2025:0577-1
SLES for SAP 15 SP5 kernel-docs +4 5.14.21-150500.55.94.1 SUSE-SU-2025:0577-2, SUSE-SU-2025:0577-1
SLE Micro 6.1 kernel-default-base 6.4.0-24.1.21.4 SUSE-SU-2025:20248-1
SLE Micro 6.1 kernel-livepatch-MICRO-6-0-RT_Update_5 1-1.1 SUSE-SU-2025:20249-1
SLE Micro 6.1 kernel-livepatch-MICRO-6-0_Update_5 1-1.2 SUSE-SU-2025:20248-1
SLE Micro 6.1 kernel-rt +4 6.4.0-25.1 SUSE-SU-2025:20249-1, SUSE-SU-2025:20248-1
SLE Micro 6.0 kernel-default-base 6.4.0-24.1.21.4 SUSE-SU-2025:20165-1
SLE Micro 6.0 kernel-livepatch-MICRO-6-0-RT_Update_5 1-1.1 SUSE-SU-2025:20166-1
SLE Micro 6.0 kernel-livepatch-MICRO-6-0_Update_5 1-1.2 SUSE-SU-2025:20165-1
SLE Micro 6.0 kernel-rt +4 6.4.0-25.1 SUSE-SU-2025:20166-1, SUSE-SU-2025:20165-1
SLE Micro 5.5 kernel-default-base 5.14.21-150500.55.94.1.150500.6.43.1 SUSE-SU-2025:0577-2, SUSE-SU-2025:0577-1
SLE Micro 5.5 kernel-rt +1 5.14.21-150500.13.85.1 SUSE-SU-2025:0556-1
SLE Micro 5.5 kernel-source +1 5.14.21-150500.55.94.1 SUSE-SU-2025:0577-2, SUSE-SU-2025:0577-1
SLE Live Patching 15 SP6 kernel-default 6.4.0-150600.23.38.1 SUSE-SU-2025:0499-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6-RT_Update_8 1-150600.1.3.1 SUSE-SU-2025:0557-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_8 1-150600.13.3.2 SUSE-SU-2025:0499-1
SLE Live Patching 15 SP5 kernel-default 5.14.21-150500.55.94.1 SUSE-SU-2025:0577-1
SLE Live Patching 15 SP5 kernel-livepatch-SLE15-SP5_Update_23 1-150500.11.3.1 SUSE-SU-2025:0577-1
SLE Live Patching 12 SP5 kernel-default 4.12.14-122.247.1 SUSE-SU-2025:0565-1
SLE Live Patching 12 SP5 kgraft-patch-SLE12-SP5_Update_65 1-8.3.1 SUSE-SU-2025:0565-1
SLE HPC 15 SP5 kernel-64kb +5 5.14.21-150500.55.94.1 SUSE-SU-2025:0577-2, SUSE-SU-2025:0577-1
SLE HPC 15 SP5 kernel-default-base 5.14.21-150500.55.94.1.150500.6.43.1 SUSE-SU-2025:0577-2, SUSE-SU-2025:0577-1
SUSE Real Time Module 15 SP6 kernel-rt +3 6.4.0-150600.10.26.1 SUSE-SU-2025:0557-1
ReleasePackageFixed inAdvisory
openSUSE Leap 15.6 dtb-aarch64 +10 6.4.0-150600.23.38.1 SUSE-SU-2025:0499-1
openSUSE Leap 15.6 kernel-azure +2 6.4.0-150600.8.26.1 SUSE-SU-2025:0428-1
openSUSE Leap 15.6 kernel-default-base 6.4.0-150600.23.38.1.150600.12.16.2 SUSE-SU-2025:0499-1
openSUSE Leap 15.6 kernel-rt +3 6.4.0-150600.10.26.1 SUSE-SU-2025:0557-1

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 kernel-livepatch-6.1.124-134.200 1.0-0.amzn2023 ALAS2023-2025-809
Amazon Linux 2023 perf +14 6.1.124-134.200.amzn2023 ALAS2023-2025-809

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 kernel 6.6.76.1-1 —
Azure Linux 2 (CBL-Mariner) kernel 5.15.176.3-1 —

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 9 kernel-uek +34 6.12.0-101.33.4.3.el10uek ELSA-2025-20530, ELSA-2025-20480

Advisories 50

References