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a5cbbea145
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Koichiro Den a5cbbea145 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>
2025-01-23 17:21:17 +01:00
..
bpf Revert "bpf: support non-r10 register spill/fill to/from stack in precision tracking" 2025-01-09 13:32:06 +01:00
cgroup cgroup/bpf: only cgroup v2 can be attached by bpf programs 2024-12-09 10:31:54 +01:00
configs Kbuild updates for v6.6 2023-09-05 11:01:47 -07:00
debug kdb: Use the passed prompt in kdb_position_cursor() 2024-08-03 08:54:34 +02:00
dma dma-debug: fix a possible deadlock on radix_lock 2024-12-14 20:00:06 +01:00
entry entry: Respect changes to system call number by trace_sys_enter() 2024-04-03 15:28:50 +02:00
events uprobes: fix kernel info leak via "[uprobes]" vma 2024-10-10 11:58:02 +02:00
futex futex: Don't include process MM in futex key on no-MMU 2023-11-20 11:58:53 +01:00
gcov gcov: add support for GCC 14 2024-06-27 13:49:13 +02:00
irq genirq/cpuhotplug: Retry with cpu_online_mask when migration fails 2024-08-19 06:04:24 +02:00
kcsan kcsan: Turn report_filterlist_lock into a raw_spinlock 2024-12-14 19:59:59 +01:00
livepatch livepatch: Fix missing newline character in klp_resolve_symbols() 2023-11-20 11:59:25 +01:00
locking lockdep: fix deadlock issue between lockdep and rcu 2024-10-04 16:30:02 +02:00
module module: Fix KCOV-ignored file name 2024-10-04 16:30:03 +02:00
power PM: s2idle: Make sure CPUs will wakeup directly on resume 2024-04-17 11:19:26 +02:00
printk printk: For @suppress_panic_printk check for other CPU in panic 2024-04-13 13:07:29 +02:00
rcu rcuscale: Do a proper cleanup if kfree_scale_init() fails 2024-12-09 10:31:50 +01:00
sched sched: Initialize idle tasks only once 2025-01-09 13:31:39 +01:00
time hrtimers: Handle CPU state correctly on hotplug 2025-01-23 17:21:17 +01:00
trace tracing: Check "%s" dereference via the field and not the TP_printk format 2025-01-09 13:31:55 +01:00
.gitignore
acct.c audit/stable-6.6 PR 20230829 2023-08-30 08:17:35 -07:00
async.c async: Introduce async_schedule_dev_nocall() 2024-01-31 16:18:49 -08:00
audit_fsnotify.c
audit_tree.c
audit_watch.c audit: don't WARN_ON_ONCE(!current->mm) in audit_exe_compare() 2023-11-28 17:19:56 +00:00
audit.c audit: Send netlink ACK before setting connection in auditd_set 2024-02-05 20:14:14 +00:00
audit.h audit: correct audit_filter_inodes() definition 2023-07-21 12:17:25 -04:00
auditfilter.c ima: Avoid blocking in RCU read-side critical section 2024-07-11 12:49:18 +02:00
auditsc.c audit,io_uring: io_uring openat triggers audit reference count underflow 2023-10-13 18:34:46 +02:00
backtracetest.c
bounds.c bounds: Use the right number of bits for power-of-two CONFIG_NR_CPUS 2024-05-02 16:32:50 +02:00
capability.c lsm: constify the 'target' parameter in security_capget() 2023-08-08 16:48:47 -04:00
cfi.c
compat.c
configs.c
context_tracking.c
cpu_pm.c
cpu.c hrtimers: Handle CPU state correctly on hotplug 2025-01-23 17:21:17 +01:00
crash_core.c mm: turn folio_test_hugetlb into a PageType 2024-05-02 16:32:47 +02:00
crash_dump.c
cred.c cred: get rid of CONFIG_DEBUG_CREDENTIALS 2023-12-20 17:01:51 +01:00
delayacct.c
dma.c
exec_domain.c
exit.c mm: optimize the redundant loop of mm_update_owner_next() 2024-07-11 12:49:15 +02:00
extable.c
fail_function.c
fork.c posix-cpu-timers: Clear TICK_DEP_BIT_POSIX_TIMER on clone 2024-11-14 13:19:37 +01:00
freezer.c
gen_kheaders.sh kheaders: Ignore silly-rename files 2025-01-23 17:21:13 +01:00
groups.c
hung_task.c
iomem.c kernel/iomem.c: remove __weak ioremap_cache helper 2023-08-21 13:37:28 -07:00
irq_work.c
jump_label.c jump_label: Fix static_key_slow_dec() yet again 2024-10-10 11:57:13 +02:00
kallsyms_internal.h
kallsyms_selftest.c Modules changes for v6.6-rc1 2023-08-29 17:32:32 -07:00
kallsyms_selftest.h
kallsyms.c kallsyms: Change func signature for cleanup_symbol_name() 2023-08-25 15:00:36 -07:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.kexec kexec: select CRYPTO from KEXEC_FILE instead of depending on it 2024-01-05 15:19:41 +01:00
Kconfig.locks
Kconfig.preempt
kcov.c kcov: mark in_softirq_really() as __always_inline 2025-01-09 13:32:07 +01:00
kexec_core.c kexec: do syscore_shutdown() in kernel_kexec 2024-01-31 16:18:56 -08:00
kexec_elf.c
kexec_file.c kexec_file: fix elfcorehdr digest exclusion when CONFIG_CRASH_HOTPLUG=y 2024-09-12 11:11:27 +02:00
kexec_internal.h
kexec.c kernel: kexec: copy user-array safely 2023-11-28 17:19:40 +00:00
kheaders.c
kprobes.c kprobes: Fix to check symbol prefixes correctly 2024-08-14 13:58:51 +02:00
ksyms_common.c
ksysfs.c crash: hotplug support for kexec_load() 2023-08-24 16:25:14 -07:00
kthread.c kthread: unpark only parked kthread 2024-10-17 15:24:37 +02:00
latencytop.c
Makefile kernel/numa.c: Move logging out of numa.h 2024-06-12 11:11:50 +02:00
module_signature.c
notifier.c
nsproxy.c nsproxy: Convert nsproxy.count to refcount_t 2023-08-21 11:29:12 -07:00
numa.c kernel/numa.c: Move logging out of numa.h 2024-06-12 11:11:50 +02:00
padata.c padata: use integer wrap around to prevent deadlock on seq_nr overflow 2024-10-04 16:29:56 +02:00
panic.c panic: Flush kernel log buffer at the end 2024-04-13 13:07:29 +02:00
params.c kernel: params: Remove unnecessary ‘0’ values from err 2023-07-10 12:47:01 -07:00
pid_namespace.c zap_pid_ns_processes: clear TIF_NOTIFY_SIGNAL along with TIF_SIGPENDING 2024-06-21 14:38:50 +02:00
pid_sysctl.h memfd: replace ratcheting feature from vm.memfd_noexec with hierarchy 2023-08-21 13:37:59 -07:00
pid.c pidfd: prevent a kernel-doc warning 2023-09-19 13:21:33 -07:00
profile.c profiling: remove profile=sleep support 2024-08-14 13:58:47 +02:00
ptrace.c
range.c
reboot.c kernel/reboot: emergency_restart: Set correct system_state 2023-11-28 17:20:04 +00:00
regset.c
relay.c kernel: relay: remove unnecessary NULL values from relay_open_buf 2023-08-18 10:18:55 -07:00
resource_kunit.c
resource.c resource: fix region_intersects() vs add_memory_driver_managed() 2024-10-10 11:57:50 +02:00
rseq.c
scftorture.c scftorture: Pause testing after memory-allocation failure 2023-07-14 15:02:57 -07:00
scs.c
seccomp.c seccomp: Add missing kerndoc notations 2023-08-17 12:32:15 -07:00
signal.c posix-timers: Target group sigqueue to current task only if not exiting 2024-12-09 10:33:11 +01:00
smp.c smp: Add missing destroy_work_on_stack() call in smp_call_on_cpu() 2024-09-12 11:11:37 +02:00
smpboot.c kthread: add kthread_stop_put 2024-06-12 11:12:52 +02:00
smpboot.h
softirq.c softirq: Allow raising SCHED_SOFTIRQ from SMP-call-function on RT kernel 2025-01-09 13:31:48 +01:00
stackleak.c
stacktrace.c
static_call_inline.c x86/static-call: provide a way to do very early static-call updates 2024-12-19 18:11:36 +01:00
static_call.c
stop_machine.c
sys_ni.c syscalls: fix compat_sys_io_pgetevents_time64 usage 2024-07-05 09:34:04 +02:00
sys.c prctl: generalize PR_SET_MDWE support check to be per-arch 2024-04-03 15:28:54 +02:00
sysctl-test.c
sysctl.c v6.5-rc1-sysctl-next 2023-06-28 16:05:21 -07:00
task_work.c task_work: make TWA_NMI_CURRENT handling conditional on IRQ_WORK 2024-11-01 01:58:34 +01:00
taskstats.c
torture.c rcutorture: Fix stuttering races and other issues 2023-11-28 17:20:08 +00:00
tracepoint.c
tsacct.c
ucount.c ucounts: fix counter leak in inc_rlimit_get_ucounts() 2024-11-14 13:19:40 +01:00
uid16.c
uid16.h
umh.c sysctl: fix unused proc_cap_handler() function warning 2023-06-29 15:19:43 -07:00
up.c
user_namespace.c
user-return-notifier.c
user.c
usermode_driver.c
utsname_sysctl.c
utsname.c
vhost_task.c vhost_task: Handle SIGKILL by flushing work and exiting 2024-07-11 12:49:10 +02:00
watch_queue.c kernel: watch_queue: copy user-array safely 2023-11-28 17:19:40 +00:00
watchdog_buddy.c watchdog/hardlockup: move SMP barriers from common code to buddy code 2023-06-19 16:25:28 -07:00
watchdog_perf.c watchdog/perf: properly initialize the turbo mode timestamp and rearm counter 2024-08-03 08:54:29 +02:00
watchdog.c watchdog: move softlockup_panic back to early_param 2023-11-28 17:19:57 +00:00
workqueue_internal.h workqueue: Drop the special locking rule for worker->flags and worker_pool->flags 2023-08-07 15:57:22 -10:00
workqueue.c workqueue: Do not warn when cancelling WQ_MEM_RECLAIM work from !WQ_MEM_RECLAIM worker 2025-01-17 13:36:25 +01:00