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Waiman Long 8d83493a46 cgroup/cpuset: Remove cpus_allowed/mems_allowed setup in cpuset_init_smp()
commit 2685027fca upstream.

There are 3 places where the cpu and node masks of the top cpuset can
be initialized in the order they are executed:
 1) start_kernel -> cpuset_init()
 2) start_kernel -> cgroup_init() -> cpuset_bind()
 3) kernel_init_freeable() -> do_basic_setup() -> cpuset_init_smp()

The first cpuset_init() call just sets all the bits in the masks.
The second cpuset_bind() call sets cpus_allowed and mems_allowed to the
default v2 values. The third cpuset_init_smp() call sets them back to
v1 values.

For systems with cgroup v2 setup, cpuset_bind() is called once.  As a
result, cpu and memory node hot add may fail to update the cpu and node
masks of the top cpuset to include the newly added cpu or node in a
cgroup v2 environment.

For systems with cgroup v1 setup, cpuset_bind() is called again by
rebind_subsystem() when the v1 cpuset filesystem is mounted as shown
in the dmesg log below with an instrumented kernel.

  [    2.609781] cpuset_bind() called - v2 = 1
  [    3.079473] cpuset_init_smp() called
  [    7.103710] cpuset_bind() called - v2 = 0

smp_init() is called after the first two init functions.  So we don't
have a complete list of active cpus and memory nodes until later in
cpuset_init_smp() which is the right time to set up effective_cpus
and effective_mems.

To fix this cgroup v2 mask setup problem, the potentially incorrect
cpus_allowed & mems_allowed setting in cpuset_init_smp() are removed.
For cgroup v2 systems, the initial cpuset_bind() call will set the masks
correctly.  For cgroup v1 systems, the second call to cpuset_bind()
will do the right setup.

cc: stable@vger.kernel.org
Signed-off-by: Waiman Long <longman@redhat.com>
Tested-by: Feng Tang <feng.tang@intel.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-18 10:28:22 +02:00
Documentation dt-bindings: pci: apple,pcie: Drop max-link-speed from example 2022-05-12 12:32:38 +02:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
arch x86/mm: Fix marking of unused sub-pmd ranges 2022-05-18 10:28:19 +02:00
block Revert "block: inherit request start time from bio for BLK_CGROUP" 2022-05-09 09:16:29 +02:00
certs certs: Fix build error when CONFIG_MODULE_SIG_KEY is empty 2022-01-23 00:08:44 +09:00
crypto crypto: xts - Add softdep on ecb 2022-04-08 13:58:36 +02:00
drivers net: phy: Fix race condition on link status change 2022-05-18 10:28:21 +02:00
fs writeback: Avoid skipping inode writeback 2022-05-18 10:28:21 +02:00
include block: Do not call folio_next() on an unreferenced folio 2022-05-18 10:28:18 +02:00
init init/main.c: return 1 from handled __setup() functions 2022-04-13 19:27:23 +02:00
ipc ipc/sem: do not sleep with a spin lock held 2022-02-04 09:25:05 -08:00
kernel cgroup/cpuset: Remove cpus_allowed/mems_allowed setup in cpuset_init_smp() 2022-05-18 10:28:22 +02:00
lib dim: initialize all struct fields 2022-05-18 10:28:14 +02:00
mm mm: mremap: fix sign for EFAULT error return value 2022-05-18 10:28:21 +02:00
net tcp: drop the hash_32() part from the index calculation 2022-05-18 10:28:18 +02:00
samples samples/bpf, xdpsock: Fix race when running for fix duration of time 2022-04-08 13:58:18 +02:00
scripts gcc-plugins: latent_entropy: use /dev/urandom 2022-04-20 09:36:24 +02:00
security Fix incorrect type in assignment of ipv6 port for audit 2022-04-08 13:58:37 +02:00
sound ASoC: SOF: Fix NULL pointer exception in sof_pci_probe callback 2022-05-18 10:28:17 +02:00
tools perf tests: Fix coresight `perf test` failure. 2022-05-18 10:28:18 +02:00
usr kbuild: remove include/linux/cyclades.h from header file check 2022-01-27 08:51:08 +01:00
virt KVM: avoid NULL pointer dereference in kvm_dirty_ring_push 2022-04-13 19:27:41 +02:00
.clang-format genirq/msi: Make interrupt allocation less convoluted 2021-12-16 22:22:20 +01:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap MAINTAINERS: Update Jisheng's email address 2022-03-08 17:30:32 +01:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: replace a Microchip AT91 maintainer 2022-02-09 11:30:01 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS net: dsa: realtek-smi: move to subdirectory 2022-04-08 13:58:12 +02:00
Makefile Linux 5.17.8 2022-05-15 20:20:54 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.