UBUNTU-CVE-2024-57951: High severity ubuntu/linux-hwe-edge vulnerability
In the Linux kernel, the following vulnerability has been resolved: hrtimers: Handle CPU state correctly on hotplug Consider a scenario where a CPU transitions from CPUHPONLINE to halfway through a CPU hotunplug down to CPUHPHRTIMERSPREPARE, and then back to CPUHPONLINE: Since hrtimerspreparecpu() does not run, cpubase.hresactive remains set to 1 throughout. However, during a CPU unplug operation, the tick and the clockevents are shut down at CPUHPAPTICKDYING. On return to the online state, for instance CFS incorrectly assumes that the hrtick is already active, and the chance of the clockevent device to transition to oneshot mode is also lost forever for the CPU, unless it goes back to a lower state than CPUHPHRTIMERSPREPARE once. This round-trip reveals another issue; cpubase.online is not set to 1 after the transition, which appears as a WARNONONCE in enqueuehrtimer(). Aside of that, the bulk of the per CPU state is not reset either, which means there are dangling pointers in the worst case. Address this by adding a corresponding startup() callback, which resets the stale per CPU state and sets the online flag. [ tglx: Make the new callback unconditionally available, remove the online modification in the prepare() callback and clear the remaining state in the starting callback instead of the prepare callback ]
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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ubuntu/linux-aws-5.4to a version that resolves this vulnerability.Fixed in 5.4.0-1142.152~18.04.1 - Upgrade
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ubuntu/linux-azure-5.4to a version that resolves this vulnerability.Fixed in 5.4.0-1147.154~18.04.1 - Upgrade
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ubuntu/linux-gcp-5.4to a version that resolves this vulnerability.Fixed in 5.4.0-1145.154~18.04.1 - Upgrade
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ubuntu/linux-hwe-5.4to a version that resolves this vulnerability.Fixed in 5.4.0-211.231~18.04.1 - Upgrade
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ubuntu/linux-ibm-5.4to a version that resolves this vulnerability.Fixed in 5.4.0-1090.95~18.04.1 - Upgrade
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ubuntu/linux-oracle-5.4to a version that resolves this vulnerability.Fixed in 5.4.0-1140.149~18.04.1 - Upgrade
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ubuntu/linux-raspi-5.4to a version that resolves this vulnerability.Fixed in 5.4.0-1129.142~18.04.1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 5.4.0-211.231 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 5.4.0-1142.152 - Upgrade
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ubuntu/linux-aws-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1080.87~20.04.1 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 5.4.0-1147.154 - Upgrade
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ubuntu/linux-azure-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1086.95~20.04.1 - Upgrade
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ubuntu/linux-bluefieldto a version that resolves this vulnerability.Fixed in 5.4.0-1101.108 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 5.4.0-1145.154 - Upgrade
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ubuntu/linux-gcp-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1081.90~20.04.1 - Upgrade
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ubuntu/linux-hwe-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-136.147~20.04.1 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 5.4.0-1088.93 - Upgrade
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ubuntu/linux-ibm-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1074.77~20.04.1 - Upgrade
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ubuntu/linux-intel-iotg-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1077.83~20.04.1 - Upgrade
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ubuntu/linux-iotto a version that resolves this vulnerability.Fixed in 5.4.0-1048.51 - Upgrade
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ubuntu/linux-kvmto a version that resolves this vulnerability.Fixed in 5.4.0-1129.138 - Upgrade
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ubuntu/linux-lowlatency-hwe-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-135.146~20.04.1 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 5.4.0-1140.150 - Upgrade
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ubuntu/linux-oracle-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1077.83~20.04.1 - Upgrade
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ubuntu/linux-raspito a version that resolves this vulnerability.Fixed in 5.4.0-1129.142 - Upgrade
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ubuntu/linux-riscv-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1075.79~20.04.1 - Upgrade
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ubuntu/linux-xilinx-zynqmpto a version that resolves this vulnerability.Fixed in 5.4.0-1060.64 - Upgrade
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ubuntu/linux-nvidia-tegra-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1039.39~20.04.1 - Upgrade
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ubuntu/linux-aws-fipsto a version that resolves this vulnerability.Fixed in 5.4.0-1142.153+fips1 - Upgrade
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ubuntu/linux-azure-fipsto a version that resolves this vulnerability.Fixed in 5.4.0-1147.154+fips1 - Upgrade
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ubuntu/linux-fipsto a version that resolves this vulnerability.Fixed in 5.4.0-1116.126 - Upgrade
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ubuntu/linux-gcp-fipsto a version that resolves this vulnerability.Fixed in 5.4.0-1145.154+fips1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 5.15.0-135.146 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 5.15.0-1080.87 - Upgrade
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ubuntu/linux-aws-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1030.32~22.04.1 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 5.15.0-1084.93 - Upgrade
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ubuntu/linux-azure-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1030.35~22.04.1 - Upgrade
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ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 5.15.0-1084.93.1 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 5.15.0-1079.88 - Upgrade
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ubuntu/linux-gcp-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1031.33~22.04.1 - Upgrade
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ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 5.15.0-1077.83 - Upgrade
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ubuntu/linux-gkeopto a version that resolves this vulnerability.Fixed in 5.15.0-1062.70 - Upgrade
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ubuntu/linux-hwe-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-64.67~22.04.1 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 5.15.0-1072.75 - Upgrade
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ubuntu/linux-ibm-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1027.27~22.04.1 - Upgrade
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ubuntu/linux-intel-iot-realtimeto a version that resolves this vulnerability.Fixed in 5.15.0-1073.75 - Upgrade
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ubuntu/linux-intel-iotgto a version that resolves this vulnerability.Fixed in 5.15.0-1075.81 - Upgrade
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ubuntu/linux-kvmto a version that resolves this vulnerability.Fixed in 5.15.0-1076.81 - Upgrade
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ubuntu/linux-lowlatencyto a version that resolves this vulnerability.Fixed in 5.15.0-135.146 - Upgrade
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ubuntu/linux-lowlatency-hwe-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-62.65.1~22.04.1 - Upgrade
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ubuntu/linux-nvidiato a version that resolves this vulnerability.Fixed in 5.15.0-1074.75 - Upgrade
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ubuntu/linux-nvidia-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1029.32~22.04.1 - Upgrade
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ubuntu/linux-nvidia-tegrato a version that resolves this vulnerability.Fixed in 5.15.0-1033.33 - Upgrade
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ubuntu/linux-nvidia-tegra-igxto a version that resolves this vulnerability.Fixed in 5.15.0-1021.21 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 5.15.0-1077.83 - Upgrade
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ubuntu/linux-oracle-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1027.28~22.04.1 - Upgrade
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ubuntu/linux-raspito a version that resolves this vulnerability.Fixed in 5.15.0-1074.77 - Upgrade
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ubuntu/linux-riscv-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-62.65~22.04.1 - Upgrade
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ubuntu/linux-xilinx-zynqmpto a version that resolves this vulnerability.Fixed in 5.15.0-1044.48 - Upgrade
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ubuntu/linux-bluefieldto a version that resolves this vulnerability.Fixed in 5.15.0-1062.64 - Upgrade
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ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 5.15.0-1080.88 - Upgrade
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ubuntu/linux-realtime-6.8to a version that resolves this vulnerability.Fixed in 6.8.1-1023.24~22.04.1 - Upgrade
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ubuntu/linux-aws-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-1080.87+fips1 - Upgrade
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ubuntu/linux-azure-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-1083.92+fips1 - Upgrade
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ubuntu/linux-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-135.146+fips1 - Upgrade
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ubuntu/linux-gcp-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-1079.88+fips1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 6.8.0-62.65 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 6.8.0-1030.32 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 6.8.0-1030.35 - Upgrade
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ubuntu/linux-azure-6.11to a version that resolves this vulnerability.Fixed in 6.11.0-1013.13~24.04.1 - Upgrade
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ubuntu/linux-azure-nvidiato a version that resolves this vulnerability.Fixed in 6.8.0-1018.19 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 6.8.0-1031.33 - Upgrade
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ubuntu/linux-gcp-6.11to a version that resolves this vulnerability.Fixed in 6.11.0-1013.13~24.04.1 - Upgrade
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ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 6.8.0-1026.30 - Upgrade
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ubuntu/linux-gkeopto a version that resolves this vulnerability.Fixed in 6.8.0-1013.15 - Upgrade
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ubuntu/linux-hwe-6.11to a version that resolves this vulnerability.Fixed in 6.11.0-24.24~24.04.1 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 6.8.0-1027.27 - Upgrade
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ubuntu/linux-lowlatencyto a version that resolves this vulnerability.Fixed in 6.8.0-62.65.1 - Upgrade
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ubuntu/linux-lowlatency-hwe-6.11to a version that resolves this vulnerability.Fixed in 6.11.0-1012.13~24.04.1 - Upgrade
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ubuntu/linux-nvidiato a version that resolves this vulnerability.Fixed in 6.8.0-1029.32 - Upgrade
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ubuntu/linux-nvidia-6.11to a version that resolves this vulnerability.Fixed in 6.11.0-1007.7 - Upgrade
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ubuntu/linux-nvidia-lowlatencyto a version that resolves this vulnerability.Fixed in 6.8.0-1029.32.1 - Upgrade
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ubuntu/linux-nvidia-tegrato a version that resolves this vulnerability.Fixed in 6.8.0-1008.8 - Upgrade
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ubuntu/linux-oem-6.11to a version that resolves this vulnerability.Fixed in 6.11.0-1020.20 - Upgrade
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ubuntu/linux-oem-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1029.29 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 6.8.0-1027.28 - Upgrade
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ubuntu/linux-raspito a version that resolves this vulnerability.Fixed in 6.8.0-1029.33 - Upgrade
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ubuntu/linux-xilinxto a version that resolves this vulnerability.Fixed in 6.8.0-1017.18 - Upgrade
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ubuntu/linux-raspi-realtimeto a version that resolves this vulnerability.Fixed in 6.8.0-2024.25 - Upgrade
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ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 6.8.1-1023.24 - Upgrade
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ubuntu/linux-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-78.78+fips1 - Compensating control
Add the hrtimers CPU startup() callback so it resets the stale per-CPU state, clears the remaining state, and sets the CPU online flag.
Event History
Frequently Asked Questions
What access would an attacker need?
The CVSS vector indicates local access and low privileges are required. The issue is associated with CPU hotplug transitions, particularly an interrupted unplug operation that returns a CPU to the online state.
Which Ubuntu kernel packages are listed as affected?
The listed packages are ubuntu/linux, ubuntu/linux-aws, ubuntu/linux-azure, ubuntu/linux-gcp, ubuntu/linux-ibm, ubuntu/linux-oracle, ubuntu/linux-raspi, and ubuntu/linux-realtime.
What signs may appear after the problematic CPU transition?
A WARN_ON_ONCE in enqueue_hrtimer() may occur because the CPU's hrtimer online state is not restored. The system can also retain stale per-CPU hrtimer state, potentially including dangling pointers, while hrtick and clockevent oneshot behavior may remain incorrectly inactive.