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Waiman Long 3fb906e7fa cgroup/cpuset: Don't filter offline CPUs in cpuset_cpus_allowed() for top cpuset tasks
Since commit 8f9ea86fdf ("sched: Always preserve the user
requested cpumask"), relax_compatible_cpus_allowed_ptr() is calling
__sched_setaffinity() unconditionally. This helps to expose a bug in
the current cpuset hotplug code where the cpumasks of the tasks in
the top cpuset are not updated at all when some CPUs become online or
offline. It is likely caused by the fact that some of the tasks in the
top cpuset, like percpu kthreads, cannot have their cpu affinity changed.

One way to reproduce this as suggested by Peter is:
 - boot machine
 - offline all CPUs except one
 - taskset -p ffffffff $$
 - online all CPUs

Fix this by allowing cpuset_cpus_allowed() to return a wider mask that
includes offline CPUs for those tasks that are in the top cpuset. For
tasks not in the top cpuset, the old rule applies and only online CPUs
will be returned in the mask since hotplug events will update their
cpumasks accordingly.

Fixes: 8f9ea86fdf ("sched: Always preserve the user requested cpumask")
Reported-by: Will Deacon <will@kernel.org>
Originally-from: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Will Deacon <will@kernel.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-02-06 10:15:08 -10:00
arch - Prevent the compiler from reordering accesses to debug regs which could cause 2023-02-05 11:28:42 -08:00
block block-6.2-2023-02-03 2023-02-03 11:35:42 -08:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-01-31 17:53:01 +09:00
crypto This update includes the following changes: 2022-12-14 12:31:09 -08:00
Documentation RTC fixes for 6.2 2023-02-04 13:46:37 -08:00
drivers USB fixes for 6.2-rc7 2023-02-05 12:19:55 -08:00
fs Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-05 17:17:10 -08:00
include Char/Misc driver fixes for 6.2-rc7 2023-02-05 11:52:23 -08:00
init Kbuild fixes for v6.2 (3rd) 2023-01-21 10:56:37 -08:00
io_uring io_uring: always prep_async for drain requests 2023-01-27 06:29:29 -07:00
ipc Non-MM patches for 6.2-rc1. 2022-12-12 17:28:58 -08:00
kernel cgroup/cpuset: Don't filter offline CPUs in cpuset_cpus_allowed() for top cpuset tasks 2023-02-06 10:15:08 -10:00
lib - Lock the proper critical section when dealing with perf event context 2023-02-05 11:03:56 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm 25 hotfixes, mainly for MM. 13 are cc:stable. 2023-02-03 10:01:57 -08:00
net linux-can-fixes-for-6.2-20230202 2023-02-02 11:51:24 -08:00
rust rust: print: avoid evaluating arguments in pr_* macros in unsafe blocks 2023-01-16 00:54:35 +01:00
samples ftrace: Export ftrace_free_filter() to modules 2023-01-24 11:20:58 -05:00
scripts Kbuild fixes for v6.2 (4th) 2023-02-04 11:30:23 -08:00
security tomoyo: Update website link 2023-01-13 23:11:38 +09:00
sound sound fixes for 6.2-rc7 2023-02-01 10:26:23 -08:00
tools ARM64: 2023-02-04 11:21:27 -08:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt VFIO fixes for v6.2-rc6 2023-01-23 11:56:07 -08:00
.clang-format iommufd for 6.2 2022-12-14 09:15:43 -08:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore *.rpm 2022-12-30 17:22:14 +09:00
.mailmap 25 hotfixes, mainly for MM. 13 are cc:stable. 2023-02-03 10:01:57 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: update SCTP maintainers 2023-02-02 11:35:33 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS USB fixes for 6.2-rc7 2023-02-05 12:19:55 -08:00
Makefile Linux 6.2-rc7 2023-02-05 13:13:28 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.