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Phil Auld 64ea6e44f8 cpu/hotplug: Make target_store() a nop when target == state
Writing the current state back in hotplug/target calls cpu_down()
which will set cpu dying even when it isn't and then nothing will
ever clear it. A stress test that reads values and writes them back
for all cpu device files in sysfs will trigger the BUG() in
select_fallback_rq once all cpus are marked as dying.

kernel/cpu.c::target_store()
	...
        if (st->state < target)
                ret = cpu_up(dev->id, target);
        else
                ret = cpu_down(dev->id, target);

cpu_down() -> cpu_set_state()
	 bool bringup = st->state < target;
	 ...
	 if (cpu_dying(cpu) != !bringup)
		set_cpu_dying(cpu, !bringup);

Fix this by letting state==target fall through in the target_store()
conditional. Also make sure st->target == target in that case.

Fixes: 757c989b99 ("cpu/hotplug: Make target state writeable")
Signed-off-by: Phil Auld <pauld@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Link: https://lore.kernel.org/r/20221117162329.3164999-2-pauld@redhat.com
2022-12-02 12:43:02 +01:00
arch - ioremap: mask out the bits which are not part of the physical address 2022-11-27 11:59:14 -08:00
block block-6.1-2022-11-25 2022-11-25 17:50:57 -08:00
certs certs: make system keyring depend on built-in x509 parser 2022-09-24 04:31:18 +09:00
crypto treewide: use get_random_bytes() when possible 2022-10-11 17:42:58 -06:00
Documentation Char/Misc driver fixes for 6.1-rc7 2022-11-27 12:17:10 -08:00
drivers USB fixes for 6.1-rc7 2022-11-27 12:30:57 -08:00
fs Amir's copy_file_range() fix 2022-11-27 12:40:06 -08:00
include Amir's copy_file_range() fix 2022-11-27 12:40:06 -08:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-11-22 22:42:38 +09:00
io_uring io_uring: clear TIF_NOTIFY_SIGNAL if set and task_work not available 2022-11-25 10:55:08 -07:00
ipc ipc/shm: call underlying open/close vm_ops 2022-11-22 18:50:42 -08:00
kernel cpu/hotplug: Make target_store() a nop when target == state 2022-12-02 12:43:02 +01:00
lib Char/Misc driver fixes for 6.1-rc7 2022-11-27 12:17:10 -08:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm 24 hotfixes. 8 marked cc:stable and 16 for post-6.0 issues. 2022-11-25 10:18:25 -08:00
net Networking fixes for 6.1-rc7, including fixes from rxrpc, netfilter and 2022-11-24 11:19:20 -08:00
rust Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
samples VFIO updates for v6.1-rc1 2022-10-12 14:46:48 -07:00
scripts - Handle different output of readelf on different distros running 2022-11-27 12:08:17 -08:00
security lsm/stable-6.1 PR 20221031 2022-10-31 12:09:42 -07:00
sound ASoC: Fixes for v6.1 2022-11-23 17:14:10 +01:00
tools x86: 2022-11-27 09:08:40 -08:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt Merge branch 'kvm-dwmw2-fixes' into HEAD 2022-11-23 18:59:45 -05:00
.clang-format PCI/DOE: Add DOE mailbox support functions 2022-07-19 15:38:04 -07:00
.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 Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap 24 hotfixes. 8 marked cc:stable and 16 for post-6.0 issues. 2022-11-25 10:18:25 -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: Remove Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
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 s390 updates for 6.1-rc7 2022-11-25 12:37:24 -08:00
Makefile Linux 6.1-rc7 2022-11-27 13:31:48 -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.