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Oleg Nesterov 5097cbcb38 sched/isolation: Prevent boot crash when the boot CPU is nohz_full
Documentation/timers/no_hz.rst states that the "nohz_full=" mask must not
include the boot CPU, which is no longer true after:

  08ae95f4fd ("nohz_full: Allow the boot CPU to be nohz_full").

However after:

  aae17ebb53 ("workqueue: Avoid using isolated cpus' timers on queue_delayed_work")

the kernel will crash at boot time in this case; housekeeping_any_cpu()
returns an invalid CPU number until smp_init() brings the first
housekeeping CPU up.

Change housekeeping_any_cpu() to check the result of cpumask_any_and() and
return smp_processor_id() in this case.

This is just the simple and backportable workaround which fixes the
symptom, but smp_processor_id() at boot time should be safe at least for
type == HK_TYPE_TIMER, this more or less matches the tick_do_timer_boot_cpu
logic.

There is no worry about cpu_down(); tick_nohz_cpu_down() will not allow to
offline tick_do_timer_cpu (the 1st online housekeeping CPU).

Fixes: aae17ebb53 ("workqueue: Avoid using isolated cpus' timers on queue_delayed_work")
Reported-by: Chris von Recklinghausen <crecklin@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240411143905.GA19288@redhat.com
Closes: https://lore.kernel.org/all/20240402105847.GA24832@redhat.com/
2024-04-28 10:07:12 +02:00
arch - Add a missing memory barrier in the concurrency ID mm switching 2024-04-21 09:39:36 -07:00
block block-6.9-20240420 2024-04-20 11:28:02 -07:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto This push fixes a regression that broke iwd as well as a divide by 2024-03-25 10:48:23 -07:00
Documentation sched/isolation: Prevent boot crash when the boot CPU is nohz_full 2024-04-28 10:07:12 +02:00
drivers Char/Misc driver fixes for 6.9-rc5 2024-04-21 10:32:58 -07:00
fs Kernfs bugfix and documentation update for 6.9-rc5 2024-04-21 10:30:21 -07:00
include Char/Misc driver fixes for 6.9-rc5 2024-04-21 10:32:58 -07:00
init init/main.c: Fix potential static_command_line memory overflow 2024-04-13 00:59:36 +09:00
io_uring io_uring/net: restore msg_control on sendzc retry 2024-04-08 21:48:41 -06:00
ipc sysctl changes for v6.9-rc1 2024-03-18 14:59:13 -07:00
kernel sched/isolation: Prevent boot crash when the boot CPU is nohz_full 2024-04-28 10:07:12 +02:00
lib hardening fixes for v6.9-rc5 2024-04-19 14:10:11 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/shmem: inline shmem_is_huge() for disabled transparent hugepages 2024-04-16 15:39:51 -07:00
net netfilter pull request 24-04-18 2024-04-18 13:12:37 +02:00
rust Kbuild updates for v6.9 2024-03-21 14:41:00 -07:00
samples Tracing updates for 6.9: 2024-03-18 15:11:44 -07:00
scripts hardening fixes for v6.9-rc4 2024-04-10 13:31:34 -07:00
security security: Place security_path_post_mknod() where the original IMA call was 2024-04-03 10:21:32 -07:00
sound ALSA: seq: ump: Fix conversion from MIDI2 to MIDI1 UMP messages 2024-04-19 12:07:14 +02:00
tools * Clean up SVM's enter/exit assembly code so that it can be compiled 2024-04-20 11:10:51 -07:00
usr Kbuild updates for v6.8 2024-01-18 17:57:07 -08:00
virt KVM: Drop unused @may_block param from gfn_to_pfn_cache_invalidate_start() 2024-04-11 12:58:53 -07:00
.clang-format clang-format: Update with v6.7-rc4's for_each macro list 2023-12-08 23:54:38 +01:00
.cocciconfig
.editorconfig Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: create a list of all built DTB files 2024-02-19 18:20:39 +09:00
.mailmap TTY/Serial driver fixes for 6.9-rc5 2024-04-21 10:27:01 -07:00
.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: Drop Gustavo Pimentel as PCI DWC Maintainer 2024-03-27 13:41:02 -05:00
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 TTY/Serial driver fixes for 6.9-rc5 2024-04-21 10:27:01 -07:00
Makefile Linux 6.9-rc5 2024-04-21 12:35:54 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -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 reStructuredText 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.