CVE-2025-71142

Summary

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

cpuset: fix warning when disabling remote partition

A warning was triggered as follows:

WARNING: kernel/cgroup/cpuset.c:1651 at remote_partition_disable+0xf7/0x110 RIP: 0010:remote_partition_disable+0xf7/0x110 RSP: 0018:ffffc90001947d88 EFLAGS: 00000206 RAX: 0000000000007fff RBX: ffff888103b6e000 RCX: 0000000000006f40 RDX: 0000000000006f00 RSI: ffffc90001947da8 RDI: ffff888103b6e000 RBP: ffff888103b6e000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: ffff88810b2e2728 R12: ffffc90001947da8 R13: 0000000000000000 R14: ffffc90001947da8 R15: ffff8881081f1c00 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f55c8bbe0b2 CR3: 000000010b14c000 CR4: 00000000000006f0 Call Trace: <TASK> update_prstate+0x2d3/0x580 cpuset_partition_write+0x94/0xf0 kernfs_fop_write_iter+0x147/0x200 vfs_write+0x35d/0x500 ksys_write+0x66/0xe0 do_syscall_64+0x6b/0x390 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7f55c8cd4887

Reproduction steps (on a 16-CPU machine):

    # cd /sys/fs/cgroup/
    # mkdir A1
    # echo +cpuset &gt; A1/cgroup.subtree_control
    # echo &#34;0-14&#34; &gt; A1/cpuset.cpus.exclusive
    # mkdir A1/A2
    # echo &#34;0-14&#34; &gt; A1/A2/cpuset.cpus.exclusive
    # echo &#34;root&#34; &gt; A1/A2/cpuset.cpus.partition
    # echo 0 &gt; /sys/devices/system/cpu/cpu15/online
    # echo member &gt; A1/A2/cpuset.cpus.partition

When CPU 15 is offlined, subpartitions_cpus gets cleared because no CPUs remain available for the top_cpuset, forcing partitions to share CPUs with the top_cpuset. In this scenario, disabling the remote partition triggers a warning stating that effective_xcpus is not a subset of subpartitions_cpus. Partitions should be invalidated in this case to inform users that the partition is now invalid(cpus are shared with top_cpuset).

To fix this issue:

  1. Only emit the warning only if subpartitions_cpus is not empty and the effective_xcpus is not a subset of subpartitions_cpus.
  2. During the CPU hotplug process, invalidate partitions if subpartitions_cpus is empty.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxf62a5d39368e34a966c8df63e1f05eed7fe9c5de < 5d8b9d38a7676be7bb5e7d57f92156a98dab39fbaffected
LinuxLinuxf62a5d39368e34a966c8df63e1f05eed7fe9c5de < aa7d3a56a20f07978d9f401e13637a6479b13bd0affected
LinuxLinux6.15affected
LinuxLinux0 < 6.15unaffected
LinuxLinux6.18.4 <= 6.18.*unaffected
LinuxLinux6.19 <= *unaffected

Weaknesses

References