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Filename Latest commit message Latest commit date
Koichiro Den 95e4f62df2 hrtimers: Handle CPU state correctly on hotplug
commit 2f8dea1692eef2b7ba6a256246ed82c365fdc686 upstream.

Consider a scenario where a CPU transitions from CPUHP_ONLINE to halfway
through a CPU hotunplug down to CPUHP_HRTIMERS_PREPARE, and then back to
CPUHP_ONLINE:

Since hrtimers_prepare_cpu() does not run, cpu_base.hres_active remains set
to 1 throughout. However, during a CPU unplug operation, the tick and the
clockevents are shut down at CPUHP_AP_TICK_DYING. On return to the online
state, for instance CFS incorrectly assumes that the hrtick is already
active, and the chance of the clockevent device to transition to oneshot
mode is also lost forever for the CPU, unless it goes back to a lower state
than CPUHP_HRTIMERS_PREPARE once.

This round-trip reveals another issue; cpu_base.online is not set to 1
after the transition, which appears as a WARN_ON_ONCE in enqueue_hrtimer().

Aside of that, the bulk of the per CPU state is not reset either, which
means there are dangling pointers in the worst case.

Address this by adding a corresponding startup() callback, which resets the
stale per CPU state and sets the online flag.

[ tglx: Make the new callback unconditionally available, remove the online
  	modification in the prepare() callback and clear the remaining
  	state in the starting callback instead of the prepare callback ]

Fixes: 5c0930ccaad5 ("hrtimers: Push pending hrtimers away from outgoing CPU earlier")
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20241220134421.3809834-1-koichiro.den@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-01 18:18:51 +01:00
arch arm64: dts: rockchip: add hevc power domain clock to rk3328 2025-02-01 18:18:49 +01:00
block blk-iocost: Avoid using clamp() on inuse in __propagate_weights() 2024-12-19 18:05:04 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:11:22 +02:00
crypto crypto: pcrypt - Call crypto layer directly when padata_do_parallel() return -EBUSY 2024-12-14 19:44:23 +01:00
Documentation PCI: Add 'reset_subordinate' to reset hierarchy below bridge 2024-12-14 19:44:54 +01:00
drivers irqchip/gic-v3: Handle CPU_PM_ENTER_FAILED correctly 2025-02-01 18:18:51 +01:00
fs fs/proc: fix softlockup in __read_vmcore (part 2) 2025-02-01 18:18:51 +01:00
include hrtimers: Handle CPU state correctly on hotplug 2025-02-01 18:18:51 +01:00
init initramfs: avoid filename buffer overrun 2024-12-14 19:44:21 +01:00
ipc ipc: replace costly bailout check in sysvipc_find_ipc() 2024-09-04 13:15:02 +02:00
kernel hrtimers: Handle CPU state correctly on hotplug 2025-02-01 18:18:51 +01:00
lib lib: string_helpers: silence snprintf() output truncation warning 2024-12-14 19:44:39 +01:00
LICENSES
mm mm: vmscan: account for free pages to prevent infinite Loop in throttle_direct_reclaim() 2025-01-09 13:23:37 +01:00
net mac802154: check local interfaces before deleting sdata list 2025-02-01 18:18:50 +01:00
samples samples/bpf: Fix a resource leak 2024-12-14 19:44:50 +01:00
scripts modpost: fix the missed iteration for the max bit in do_input() 2025-01-09 13:23:36 +01:00
security selinux: ignore unknown extended permissions 2025-01-09 13:23:33 +01:00
sound sound: usb: format: don't warn that raw DSD is unsupported 2025-01-09 13:23:36 +01:00
tools perf trace: Avoid garbage when not printing a syscall's arguments 2024-12-14 19:44:32 +01:00
usr
virt KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow status 2024-12-19 18:05:04 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Remove *.orig pattern from .gitignore 2024-11-08 16:20:33 +01:00
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-30 16:27:12 +02:00
Makefile Linux 5.4.289 2025-01-09 13:23:37 +01:00
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.