p PatchFirst

CVE-2026-99065

CVE-2026-99065 · cgroup/cpuset: Handle cpu hotplug race in guarantee_active_cpus()

This page contains facts from public vulnerability sources. Check the original advisory before updating.

In the Linux kernel, the following vulnerability has been resolved: cgroup/cpuset: Handle cpu hotplug race in guarantee_active_cpus() With commit 2125c0034c5d ("cgroup/cpuset: Make cpuset hotplug processing synchronous"), the cpuset hotplug operation becomes synchronous. That commit also removes the code that handles race between cpuset_hotplug_work and cpu hotplug notifier with the assumption that race is now gone. Later commit 7a0aabd9ce69 ("cgroup/cpuset: Always use cpu_active_mask") updates the cpuset code to always use cpu_active_mask instead of cpu_online_mask in some places including guarantee_online_cpus() which is renamed to guarantee_active_cpus() in that commit. In the case of CPU offline operation, cpu_active_mask is updated first in sched_cpu_deactivate() to remove the offline CPU before cpuset_handle_hotplug() is called to update the effective_cpus of the affected cpusets. The cpu_online_mask is updated after that near the end of the offline operation to remove the offline CPU. As a result, the race comes back and the top cpuset may not have any active CPU leading to NULL pointer dereference during the race window when guarantee_active_cpus() is called after cpu_active_mask is updated to remove the CPU to be torn down but before cpuset_handle_hotplug() is able to properly update the effective_cpus of the top cpuset. Fix this by adding back the NULL cs check to avoid this problem.

Fix available

Published
Updated

Stack: system

Affected products and versions

  • linux

    Versions
    • ≥ 7a0aabd9ce697fc581ec691b21f748050fbcf004, < 8d88d3221204fbb1b6dc2c0f2f2181fe49126639: Affected (git)
    • ≥ 7a0aabd9ce697fc581ec691b21f748050fbcf004, < a21c255159bfe0034740292e10d2e258feeeb10d: Affected (git)
    • ≥ 7a0aabd9ce697fc581ec691b21f748050fbcf004, < 23b1ab15ca91f2cffaf149d9bb0fafeb700c7db2: Affected (git)

    Update to 8d88d3221204fbb1b6dc2c0f2f2181fe49126639

  • linux

    Versions
    • 6.16: Affected
    • ≥ 0, < 6.16: Not affected (semver)
    • ≥ 6.18.57, ≤ 6.18.*: Not affected (semver)
    • ≥ 7.2.11, ≤ 7.2.*: Not affected (semver)
    • ≥ 7.3: Not affected (original_commit_for_fix)

    No fix published

  • linux Debian:14

    Versions
    • 6.12.100-1
    • 6.12.101-1
    • 6.12.105-1
    • 6.12.107-1
    • 6.12.111-1
    • 6.12.113-1
    • 6.12.38-1
    • 6.12.41-1
    • 6.12.43-1
    • 6.12.43-1~bpo12+1
    • 6.12.48-1
    • 6.12.57-1
    • 6.12.57-1~bpo12+1
    • 6.12.63-1
    • 6.12.63-1~bpo12+1
    • 6.12.69-1
    • 6.12.69-1~bpo12+1
    • 6.12.73-1
    • 6.12.73-1~bpo12+1
    • 6.12.74-1
    • 6.12.74-2
    • 6.12.74-2~bpo12+1
    • 6.12.85-1
    • 6.12.85-1~bpo12+1
    • 6.12.86-1
    • 6.12.86-1~bpo12+1
    • 6.12.88-1
    • 6.12.88-1~bpo12+1
    • 6.12.90-1
    • 6.12.90-1~bpo12+1
    • 6.12.90-2
    • 6.12.90-2~bpo12+1
    • 6.12.94-1
    • 6.12.94-1~bpo12+1
    • 6.12.95-1
    • 6.12.95-1~bpo12+1
    • 6.12.96-1
    • 6.13.10-1~exp1
    • 6.13.11-1~exp1
    • 6.13.2-1~exp1
    • 6.13.3-1~exp1
    • 6.13.4-1~exp1
    • 6.13.5-1~exp1
    • 6.13.6-1~exp1
    • 6.13.7-1~exp1
    • 6.13.8-1~exp1
    • 6.13.9-1~exp1
    • 6.13~rc6-1~exp1
    • 6.13~rc7-1~exp1
    • 6.14.3-1~exp1
    • 6.14.5-1~exp1
    • 6.14.6-1~exp1
    • 6.15-1~exp1
    • 6.15.1-1~exp1
    • 6.15.2-1~exp1
    • 6.15.3-1~exp1
    • 6.15.4-1~exp1
    • 6.15.5-1~exp1
    • 6.15.6-1~exp1
    • 6.15~rc7-1~exp1
    • 6.16-1~exp1
    • 6.16.1-1~exp1
    • 6.16.10-1
    • 6.16.11-1
    • 6.16.12-1
    • 6.16.12-1~bpo13+1
    • 6.16.12-2
    • 6.16.3-1
    • 6.16.3-1~bpo13+1
    • 6.16.5-1
    • 6.16.6-1
    • 6.16.7-1
    • 6.16.8-1
    • 6.16.9-1
    • 6.16~rc7-1~exp1
    • 6.17.10-1
    • 6.17.11-1
    • 6.17.12-1
    • 6.17.13-1
    • 6.17.13-1~bpo13+1
    • 6.17.2-1~exp1
    • 6.17.5-1~exp1
    • 6.17.6-1
    • 6.17.7-1
    • 6.17.7-2
    • 6.17.8-1
    • 6.17.8-1~bpo13+1
    • 6.17.9-1
    • 6.18.1-1~exp1
    • 6.18.10-1
    • 6.18.12-1
    • 6.18.12-1~bpo13+1
    • 6.18.13-1
    • 6.18.14-1
    • 6.18.15-1
    • 6.18.15-1~bpo13+1
    • 6.18.2-1~exp1
    • 6.18.3-1
    • 6.18.5-1
    • 6.18.5-1~bpo13+1
    • 6.18.8-1
    • 6.18.9-1
    • 6.18.9-1~bpo13+1
    • 6.18~rc4-1~exp1
    • 6.18~rc4-1~exp2
    • 6.18~rc5-1~exp1
    • 6.18~rc6-1~exp1
    • 6.18~rc7-1~exp1
    • 6.19-1~exp1
    • 6.19.10-1
    • 6.19.10-1~bpo13+1
    • 6.19.11-1
    • 6.19.11-1~bpo13+1
    • 6.19.12-1
    • 6.19.13-1
    • 6.19.13-1~bpo13+1
    • 6.19.14-1
    • 6.19.14-1~bpo13+1
    • 6.19.2-1~exp1
    • 6.19.3-1~exp1
    • 6.19.4-1~exp1
    • 6.19.5-1~exp1
    • 6.19.6-1
    • 6.19.6-2
    • 6.19.6-2~bpo13+1
    • 6.19.8-1
    • 6.19.8-1~bpo13+1
    • 6.19~rc4-1~exp1
    • 6.19~rc5-1~exp1
    • 6.19~rc6-1~exp1
    • 6.19~rc7-1~exp1
    • 6.19~rc8-1~exp1
    • 7.0-1~exp1
    • 7.0.1-1~exp1
    • 7.0.10-1
    • 7.0.10-1~bpo13+1
    • 7.0.12-1
    • 7.0.12-2
    • 7.0.12-2~bpo13+1
    • 7.0.13-1
    • 7.0.13-1~bpo13+1
    • 7.0.14-1
    • 7.0.3-1
    • 7.0.4-1
    • 7.0.4-1~bpo13+1
    • 7.0.7-1
    • 7.0.7-1~bpo13+1
    • 7.0.9-1
    • 7.0.9-1~bpo13+1
    • 7.1.1-1~exp1
    • 7.1.10-1
    • 7.1.12-1
    • 7.1.13-1
    • 7.1.13-1~bpo13+1
    • 7.1.2-1~exp1
    • 7.1.3-1
    • 7.1.3-1+sunvdc
    • 7.1.3-1~bpo13+1
    • 7.1.4-1
    • 7.1.5-1
    • 7.1.6-1
    • 7.1.7-1
    • 7.1.7-1~bpo13+1
    • 7.1.8-1
    • 7.1.8-1~bpo13+1
    • 7.1.8-2
    • 7.1.9-1
    • 7.1.9-1+sparc64
    • 7.1~rc2-1~exp1
    • 7.1~rc3-1~exp1
    • 7.1~rc4-1~exp1
    • 7.1~rc4-1~exp2
    • 7.1~rc5-1~exp1
    • 7.1~rc7-1~exp1
    • 7.2.10-1
    • 7.2.2-1~exp1
    • 7.2.3-1~exp1
    • 7.2.6-1
    • 7.2.6-1~bpo13+1
    • 7.2.7-1
    • 7.2.8-1
    • 7.2.9-1
    • 7.2.9-1~bpo13+1
    • 7.2~rc3-1~exp1
    • 7.2~rc5-1~exp1
    • 7.2~rc7-1~exp1
    Affected ranges
    • ECOSYSTEM: < 7.2.11-1

    Update to 7.2.11-1

Original sources

Check your server →