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OpenAdvisories
High · 7.8 CVE-2025-21823 EUVD-2025-5979GHSA-cq4r-9fv8-53r2

batman-adv: Drop unmanaged ELP metric worker

Published Feb 27, 2025 · Updated Aug 5, 2026 · Assigned by Linux

Vendor: Linux Product: Linux 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 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-6.11 Package: linux-lowlatency-hwe-6.2 Package: linux-lowlatency-hwe-6.5 Package: linux-lowlatency-hwe-6.8 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: Debian Ecosystem: Ubuntu

Description

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

batman-adv: Drop unmanaged ELP metric worker

The ELP worker needs to calculate new metric values for all neighbors
"reachable" over an interface. Some of the used metric sources require
locks which might need to sleep. This sleep is incompatible with the RCU
list iterator used for the recorded neighbors. The initial approach to work
around of this problem was to queue another work item per neighbor and then
run this in a new context.

Even when this solved the RCU vs might_sleep() conflict, it has a major
problems: Nothing was stopping the work item in case it is not needed
anymore - for example because one of the related interfaces was removed or
the batman-adv module was unloaded - resulting in potential invalid memory
accesses.

Directly canceling the metric worker also has various problems:

* cancel_work_sync for a to-be-deactivated interface is called with
rtnl_lock held. But the code in the ELP metric worker also tries to use
rtnl_lock() - which will never return in this case. This also means that
cancel_work_sync would never return because it is waiting for the worker
to finish.
* iterating over the neighbor list for the to-be-deactivated interface is
currently done using the RCU specific methods. Which means that it is
possible to miss items when iterating over it without the associated
spinlock - a behaviour which is acceptable for a periodic metric check
but not for a cleanup routine (which must "stop" all still running
workers)

The better approch is to get rid of the per interface neighbor metric
worker and handle everything in the interface worker. The original problems
are solved by:

* creating a list of neighbors which require new metric information inside
the RCU protected context, gathering the metric according to the new list
outside the RCU protected context
* only use rcu_trylock inside metric gathering code to avoid a deadlock
when the cancel_delayed_work_sync is called in the interface removal code
(which is called with the rtnl_lock held)

Affected products

VendorProductAffectedFixed
Linux Linux 4.6 5.4.291

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 6.12.16-1 —
Debian 13 linux 6.12.16-1 —
Debian 12 linux 6.1.129-1 —
Debian 11 linux 5.10.237-1 DLA-4178-1
Debian 11 linux-6.1 6.1.129-1~deb11u1 DLA-4102-1
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 22.04 LTS linux-bluefield 5.15.0-1066.68 —
Ubuntu 24.04 LTS linux 6.8.0-78.78 USN-7703-1
Ubuntu 24.04 LTS linux-aws 6.8.0-1035.37 USN-7703-1
Ubuntu 24.04 LTS linux-azure 6.8.0-1034.39 USN-7737-1
Ubuntu 24.04 LTS linux-azure-nvidia 6.8.0-1022.23 USN-7737-1
Ubuntu 24.04 LTS linux-gcp 6.8.0-1036.38 USN-7703-2
Ubuntu 24.04 LTS linux-gcp-6.11 +1 6.11.0-1015.15~24.04.1 USN-7521-1
Ubuntu 24.04 LTS linux-gke 6.8.0-1032.36 USN-7703-4
Ubuntu 24.04 LTS linux-gkeop 6.8.0-1019.21 USN-7703-2
Ubuntu 24.04 LTS linux-hwe-6.11 6.11.0-26.26~24.04.1 USN-7521-1
Ubuntu 24.04 LTS linux-ibm 6.8.0-1033.33 USN-7703-2
Ubuntu 24.04 LTS linux-intel +4 No fix yet —
Ubuntu 24.04 LTS linux-lowlatency 6.8.0-78.78.1 USN-7703-1
Ubuntu 24.04 LTS linux-lowlatency-hwe-6.11 6.11.0-1014.15~24.04.1 USN-7521-3
Ubuntu 24.04 LTS linux-nvidia 6.8.0-1035.38 USN-7703-4
Ubuntu 24.04 LTS linux-nvidia-6.11 6.11.0-1010.10 —
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1035.38.1 USN-7703-4
Ubuntu 24.04 LTS linux-nvidia-tegra 6.8.0-1009.9 —
Ubuntu 24.04 LTS linux-oem-6.11 6.11.0-1022.22 USN-7521-1
Ubuntu 24.04 LTS linux-oracle 6.8.0-1032.33 USN-7703-3
Ubuntu 24.04 LTS linux-raspi 6.8.0-1035.39 USN-7703-4
Ubuntu 24.04 LTS linux-xilinx 6.8.0-1017.18 —
Ubuntu 22.04 LTS linux +1 5.15.0-140.150 USN-7510-1
Ubuntu 22.04 LTS linux-aws 5.15.0-1084.91 USN-7510-7
Ubuntu 22.04 LTS linux-aws-6.8 6.8.0-1035.37~22.04.1 USN-7703-2
Ubuntu 22.04 LTS linux-azure 5.15.0-1089.98 USN-7510-3
Ubuntu 22.04 LTS linux-azure-6.8 6.8.0-1034.39~22.04.1 USN-7737-1
Ubuntu 22.04 LTS linux-azure-fde 5.15.0-1089.98.1 —
Ubuntu 22.04 LTS linux-gcp 5.15.0-1083.92 USN-7511-1
Ubuntu 22.04 LTS linux-gcp-6.8 6.8.0-1036.38~22.04.1 USN-7703-2
Ubuntu 22.04 LTS linux-gke +1 5.15.0-1081.87 USN-7511-3, USN-7510-1
Ubuntu 22.04 LTS linux-gkeop 5.15.0-1066.74 USN-7510-1
Ubuntu 22.04 LTS linux-hwe-6.8 +1 6.8.0-78.78~22.04.1 USN-7703-4
Ubuntu 22.04 LTS linux-ibm 5.15.0-1076.79 USN-7510-1
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1033.33~22.04.1 USN-7703-2
Ubuntu 22.04 LTS linux-intel-iotg 5.15.0-1079.85 USN-7510-1
Ubuntu 22.04 LTS linux-kvm 5.15.0-1080.85 USN-7510-1
Ubuntu 22.04 LTS linux-lowlatency-hwe-6.8 6.8.0-78.78.1~22.04.1 USN-7703-1
Ubuntu 22.04 LTS linux-nvidia 5.15.0-1078.79 USN-7510-1
Ubuntu 22.04 LTS linux-nvidia-6.8 6.8.0-1035.38~22.04.1 USN-7703-4
Ubuntu 22.04 LTS linux-nvidia-tegra 5.15.0-1037.37 USN-7510-3
Ubuntu 22.04 LTS linux-nvidia-tegra-igx 5.15.0-1026.26 USN-7510-7
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1032.33~22.04.1 USN-7703-3
Ubuntu 22.04 LTS linux-raspi 5.15.0-1078.81 USN-7510-7
Ubuntu 22.04 LTS linux-riscv +32 No fix yet —
Ubuntu 22.04 LTS linux-xilinx-zynqmp 5.15.0-1050.54 USN-7602-1
Ubuntu 20.04 LTS linux 5.4.0-216.236 USN-7516-1
Ubuntu 20.04 LTS linux-aws 5.4.0-1146.156 USN-7516-9
Ubuntu 20.04 LTS linux-aws-5.15 5.15.0-1084.91~20.04.1 USN-7510-8
Ubuntu 20.04 LTS linux-azure 5.4.0-1151.158 USN-7516-3
Ubuntu 20.04 LTS linux-azure-5.15 5.15.0-1089.98~20.04.1 USN-7510-3
Ubuntu 20.04 LTS linux-bluefield 5.4.0-1105.112 USN-7517-3
Ubuntu 20.04 LTS linux-gcp 5.4.0-1149.158 USN-7516-1
Ubuntu 20.04 LTS linux-gcp-5.15 5.15.0-1083.92~20.04.1 USN-7512-1
Ubuntu 20.04 LTS linux-gke +28 No fix yet —
Ubuntu 20.04 LTS linux-ibm 5.4.0-1092.97 USN-7516-6
Ubuntu 20.04 LTS linux-ibm-5.15 5.15.0-1076.79~20.04.1 USN-7510-1
Ubuntu 20.04 LTS linux-intel-iotg-5.15 5.15.0-1079.85~20.04.1 USN-7510-7
Ubuntu 20.04 LTS linux-kvm 5.4.0-1133.142 USN-7516-3
Ubuntu 20.04 LTS linux-lowlatency-hwe-5.15 5.15.0-140.150~20.04.1 USN-7510-1
Ubuntu 20.04 LTS linux-oracle 5.4.0-1144.154 USN-7516-1
Ubuntu 20.04 LTS linux-oracle-5.15 5.15.0-1081.87~20.04.1 USN-7510-1
Ubuntu 20.04 LTS linux-raspi 5.4.0-1129.142 USN-7539-1
Ubuntu 20.04 LTS linux-riscv-5.15 5.15.0-1079.83~20.04.1 —
Ubuntu 20.04 LTS linux-xilinx-zynqmp 5.4.0-1064.68 USN-7517-1
Ubuntu 18.04 LTS linux-gcp +14 No fix yet —
Show 14 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 6.8.0-2028.29 USN-7719-1
Ubuntu Pro Realtime 24.04 LTS linux-realtime 6.8.1-1030.31 USN-7703-1
Ubuntu Pro Realtime 22.04 LTS linux-intel-iot-realtime 5.15.0-1077.79 USN-7510-4
Ubuntu Pro Realtime 22.04 LTS linux-realtime 5.15.0-1084.93 USN-7510-4
Ubuntu Pro Realtime 22.04 LTS linux-realtime-6.8 6.8.1-1030.31~22.04.1 —
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-updates 24.04 LTS linux-fips 6.8.0-78.78+fips1 —
Ubuntu Pro FIPS-updates 22.04 LTS linux-aws-fips 5.15.0-1084.91+fips1 USN-7510-6
Ubuntu Pro FIPS-updates 22.04 LTS linux-azure-fips 5.15.0-1089.98+fips1 USN-7510-5
Ubuntu Pro FIPS-updates 22.04 LTS linux-fips 5.15.0-140.150+fips1 USN-7510-2
Ubuntu Pro FIPS-updates 22.04 LTS linux-gcp-fips 5.15.0-1083.92+fips1 USN-7511-2
Ubuntu Pro FIPS-updates 20.04 LTS linux-aws-fips 5.4.0-1146.156+fips1 USN-7516-8
Ubuntu Pro FIPS-updates 20.04 LTS linux-azure-fips 5.4.0-1151.158+fips1 USN-7518-1
Ubuntu Pro FIPS-updates 20.04 LTS linux-fips 5.4.0-1120.130 USN-7516-8
Ubuntu Pro FIPS-updates 20.04 LTS linux-gcp-fips 5.4.0-1149.158+fips1 USN-7516-2
Ubuntu Pro FIPS-updates 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-preview 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro 20.04 LTS linux-hwe-5.15 5.15.0-142.152~20.04.1 USN-7593-1
Ubuntu Pro 20.04 LTS linux-iot 5.4.0-1051.54 USN-7640-1
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 5.4.0-1146.156~18.04.1 USN-7516-7
Ubuntu Pro 18.04 LTS linux-azure-5.4 5.4.0-1151.158~18.04.1 USN-7516-1
Ubuntu Pro 18.04 LTS linux-gcp-5.4 5.4.0-1149.158~18.04.1 USN-7516-1
Ubuntu Pro 18.04 LTS linux-hwe-5.4 5.4.0-216.236~18.04.1 USN-7516-5
Ubuntu Pro 18.04 LTS linux-ibm-5.4 5.4.0-1092.97~18.04.1 USN-7517-2
Ubuntu Pro 18.04 LTS linux-oracle-5.4 5.4.0-1144.154~18.04.1 USN-7516-4
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-gcp +4 No fix yet —
Ubuntu Pro 14.04 LTS linux-azure No fix yet —
ReleasePackageFixed inAdvisory
SLES 15 SP6 kernel-64kb +3 6.4.0-150600.23.47.2 SUSE-SU-2025:1180-1
SLES 15 SP6 kernel-azure +1 6.4.0-150600.8.34.2 SUSE-SU-2025:1177-1
SLES 15 SP6 kernel-coco +3 6.4.0-15061.21.coco15sp6.1 SUSE-SU-2025:01919-1
SLES 15 SP6 kernel-default-base 6.4.0-150600.23.47.2.150600.12.20.2 SUSE-SU-2025:1180-1
SLES 15 SP6 kernel-docs +2 6.4.0-150600.23.47.1 SUSE-SU-2025:1180-1
SLES 15 SP6 kernel-syms-azure 6.4.0-150600.8.34.1 SUSE-SU-2025:1177-1
Show 4 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLE Micro 6.1 kernel-default-base 6.4.0-28.1.21.6 SUSE-SU-2025:20270-1
SLE Micro 6.1 kernel-livepatch-MICRO-6-0_Update_6 +1 1-3.1 SUSE-SU-2025:20270-1, SUSE-SU-2025:20260-1
SLE Micro 6.1 kernel-rt +4 6.4.0-28.1 SUSE-SU-2025:20270-1, SUSE-SU-2025:20260-1
SLE Micro 6.0 kernel-default-base 6.4.0-28.1.21.6 SUSE-SU-2025:20192-1
SLE Micro 6.0 kernel-livepatch-MICRO-6-0_Update_6 +1 1-3.1 SUSE-SU-2025:20192-1, SUSE-SU-2025:20190-1
SLE Micro 6.0 kernel-rt +4 6.4.0-28.1 SUSE-SU-2025:20192-1, SUSE-SU-2025:20190-1
SLE Live Patching 15 SP6 kernel-default 6.4.0-150600.23.47.2 SUSE-SU-2025:1180-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6-RT_Update_10 1-150600.1.5.1 SUSE-SU-2025:1178-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_10 1-150600.13.5.1 SUSE-SU-2025:1180-1
SUSE Real Time Module 15 SP6 kernel-rt +3 6.4.0-150600.10.34.1 SUSE-SU-2025:1178-1
ReleasePackageFixed inAdvisory
openSUSE Leap 15.6 dtb-aarch64 +4 6.4.0-150600.23.47.1 SUSE-SU-2025:1180-1
openSUSE Leap 15.6 kernel-64kb +5 6.4.0-150600.23.47.2 SUSE-SU-2025:1180-1
openSUSE Leap 15.6 kernel-azure +1 6.4.0-150600.8.34.2 SUSE-SU-2025:1177-1
openSUSE Leap 15.6 kernel-default-base 6.4.0-150600.23.47.2.150600.12.20.2 SUSE-SU-2025:1180-1
openSUSE Leap 15.6 kernel-rt +3 6.4.0-150600.10.34.1 SUSE-SU-2025:1178-1
openSUSE Leap 15.6 kernel-syms-azure 6.4.0-150600.8.34.1 SUSE-SU-2025:1177-1

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