Chen Ridong 8b1f3c54f9 cpuset: fix overlap of partition effective CPUs
A warning was detect:

 WARNING: kernel/cgroup/cpuset.c:825 at rebuild_sched_domains_locked
 Modules linked in:
 CPU: 12 UID: 0 PID: 681 Comm: rmdir  6.19.0-rc6-next-20260121+
 RIP: 0010:rebuild_sched_domains_locked+0x309/0x4b0
 RSP: 0018:ffffc900019bbd28 EFLAGS: 00000202
 RAX: ffff888104413508 RBX: 0000000000000008 RCX: ffff888104413510
 RDX: ffff888109b5f400 RSI: 000000000000ffcf RDI: 0000000000000001
 RBP: 0000000000000002 R08: ffff888104413508 R09: 0000000000000002
 R10: ffff888104413508 R11: 0000000000000001 R12: ffff888104413500
 R13: 0000000000000002 R14: ffffc900019bbd78 R15: 0000000000000000
 FS:  00007fe274b8d740(0000) GS:ffff8881b6b3c000(0000) knlGS:
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007fe274c98b50 CR3: 00000001047a9000 CR4: 00000000000006f0
 Call Trace:
  <TASK>
  update_prstate+0x1c7/0x580
  cpuset_css_killed+0x2f/0x50
  kill_css+0x32/0x180
  cgroup_destroy_locked+0xa7/0x200
  cgroup_rmdir+0x28/0x100
  kernfs_iop_rmdir+0x4c/0x80
  vfs_rmdir+0x12c/0x280
  filename_rmdir+0x19e/0x200
  __x64_sys_rmdir+0x23/0x40
  do_syscall_64+0x6b/0x390

It can be reproduced by steps:

  # cd /sys/fs/cgroup/
  # mkdir A1
  # mkdir B1
  # mkdir C1
  # echo 1-3 > A1/cpuset.cpus
  # echo root > A1/cpuset.cpus.partition
  # echo 3-5 > B1/cpuset.cpus
  # echo root > B1/cpuset.cpus.partition
  # echo 6 > C1/cpuset.cpus
  # echo root > C1/cpuset.cpus.partition
  # rmdir A1/
  # rmdir C1/

Both A1 and B1 were initially configured with CPU 3, which was exclusively
assigned to A1's partition. When A1 was removed, CPU 3 was returned to the
root pool. However, B1 incorrectly regained access to CPU 3 when
update_cpumasks_hier was triggered during C1's removal, which also updated
sibling configurations.

The update_sibling_cpumasks function was called to synchronize siblings'
effective CPUs due to changes in their parent's effective CPUs. However,
parent effective CPU changes should not affect partition-effective CPUs.

To fix this issue, update_cpumasks_hier should only be invoked when the
sibling is not a valid partition in the update_sibling_cpumasks.

Fixes: 2a3602030d ("cgroup/cpuset: Don't invalidate sibling partitions on cpuset.cpus conflict")
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2026-02-01 06:49:52 -10:00
2022-09-28 09:02:20 +02:00
2025-11-12 10:00:14 -08:00
2025-02-19 14:53:27 -07:00

Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer - Getting started with kernel development
* Academic Researcher - Studying kernel internals and architecture
* Security Expert - Hardening and vulnerability analysis
* Backport/Maintenance Engineer - Maintaining stable kernels
* System Administrator - Configuring and troubleshooting
* Maintainer - Leading subsystems and reviewing patches
* Hardware Vendor - Writing drivers for new hardware
* Distribution Maintainer - Packaging kernels for distros


For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst



Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
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