linux/kernel
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
..
bpf bpf: Initialize same number of free nodes for each pcpu_freelist 2022-11-11 12:05:14 -08:00
cgroup cgroup fixes for v6.1-rc1 2022-10-17 18:52:43 -07:00
configs Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
debug mm: remove vmacache 2022-09-26 19:46:18 -07:00
dma - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in 2022-10-10 17:53:04 -07:00
entry entry: kmsan: introduce kmsan_unpoison_entry_regs() 2022-10-03 14:03:25 -07:00
events perf: Consider OS filter fail 2022-11-24 10:12:23 +01:00
futex freezer,sched: Rewrite core freezer logic 2022-09-07 21:53:50 +02:00
gcov gcov: clang: fix the buffer overflow issue 2022-11-22 18:50:41 -08:00
irq genirq: Provide generic_handle_domain_irq_safe(). 2022-09-19 15:08:38 +02:00
kcsan treewide: use get_random_bytes() when possible 2022-10-11 17:42:58 -06:00
livepatch Livepatching changes for 6.1 2022-10-10 11:36:19 -07:00
locking treewide: use prandom_u32_max() when possible, part 1 2022-10-11 17:42:55 -06:00
module module: tracking: Keep a record of tainted unloaded modules only 2022-10-10 12:16:19 -07:00
power PM: hibernate: Allow hybrid sleep to work with s2idle 2022-10-25 14:53:19 +02:00
printk printk: Mark __printk percpu data ready __ro_after_init 2022-09-29 15:20:52 +02:00
rcu rcu: Keep synchronize_rcu() from enabling irqs in early boot 2022-10-20 15:34:49 -07:00
sched Revert "cpufreq: schedutil: Move max CPU capacity to sugov_policy" 2022-11-22 19:56:52 +01:00
time treewide: use prandom_u32_max() when possible, part 1 2022-10-11 17:42:55 -06:00
trace tracing/probes: Fixes for v6.1 2022-11-20 15:31:20 -08:00
.gitignore
acct.c acct: use VMA iterator instead of linked list 2022-09-26 19:46:22 -07:00
async.c
audit_fsnotify.c audit: fix potential double free on error path from fsnotify_add_inode_mark 2022-08-22 18:50:06 -04:00
audit_tree.c
audit_watch.c audit_init_parent(): constify path 2022-09-01 17:39:30 -04:00
audit.c audit: use time_after to compare time 2022-08-29 19:47:03 -04:00
audit.h audit: remove selinux_audit_rule_update() declaration 2022-09-07 11:30:15 -04:00
auditfilter.c
auditsc.c audit/stable-6.1 PR 20221003 2022-10-04 11:05:43 -07:00
backtracetest.c
bounds.c mm: multi-gen LRU: minimal implementation 2022-09-26 19:46:09 -07:00
capability.c
cfi.c cfi: Switch to -fsanitize=kcfi 2022-09-26 10:13:13 -07:00
compat.c
configs.c
context_tracking.c MAINTAINERS: Add Paul as context tracking maintainer 2022-07-05 13:33:00 -07:00
cpu_pm.c context_tracking: Take IRQ eqs entrypoints over RCU 2022-07-05 13:32:59 -07:00
cpu.c cpu/hotplug: Make target_store() a nop when target == state 2022-12-02 12:43:02 +01:00
crash_core.c vmcoreinfo: add kallsyms_num_syms symbol 2022-08-28 14:02:44 -07:00
crash_dump.c
cred.c
delayacct.c delayacct: support re-entrance detection of thrashing accounting 2022-09-26 19:46:07 -07:00
dma.c
exec_domain.c
exit.c - hfs and hfsplus kmap API modernization from Fabio Francesco 2022-10-12 11:00:22 -07:00
extable.c context_tracking: Take NMI eqs entrypoints over RCU 2022-07-05 13:32:59 -07:00
fail_function.c fail_function: fix wrong use of fei_attr_remove() 2022-09-11 21:55:11 -07:00
fork.c - hfs and hfsplus kmap API modernization from Fabio Francesco 2022-10-12 11:00:22 -07:00
freezer.c freezer,sched: Rewrite core freezer logic 2022-09-07 21:53:50 +02:00
gen_kheaders.sh kbuild: build init/built-in.a just once 2022-09-29 04:40:15 +09:00
groups.c security: Add LSM hook to setgroups() syscall 2022-07-15 18:21:49 +00:00
hung_task.c sched: Fix more TASK_state comparisons 2022-09-30 16:50:39 +02:00
iomem.c
irq_work.c
jump_label.c jump_label: make initial NOP patching the special case 2022-06-24 09:48:55 +02:00
kallsyms_internal.h kallsyms: move declarations to internal header 2022-07-17 17:31:39 -07:00
kallsyms.c kcfi updates for v6.1-rc1 2022-10-03 17:11:07 -07:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c kcov: kmsan: unpoison area->list in kcov_remote_area_put() 2022-10-03 14:03:23 -07:00
kexec_core.c kexec: replace kmap() with kmap_local_page() 2022-09-11 21:55:08 -07:00
kexec_elf.c
kexec_file.c panic, kexec: make __crash_kexec() NMI safe 2022-09-11 21:55:06 -07:00
kexec_internal.h panic, kexec: make __crash_kexec() NMI safe 2022-09-11 21:55:06 -07:00
kexec.c panic, kexec: make __crash_kexec() NMI safe 2022-09-11 21:55:06 -07:00
kheaders.c
kmod.c
kprobes.c kprobes: Skip clearing aggrprobe's post_handler in kprobe-on-ftrace case 2022-11-18 10:15:34 +09:00
ksysfs.c kexec: turn all kexec_mutex acquisitions into trylocks 2022-09-11 21:55:06 -07:00
kthread.c signal: break out of wait loops on kthread_stop() 2022-10-09 16:01:59 -07:00
latencytop.c latencytop: use the last element of latency_record of system 2022-09-11 21:55:12 -07:00
Makefile kmsan: disable instrumentation of unsupported common kernel code 2022-10-03 14:03:20 -07:00
module_signature.c
notifier.c notifier: Add blocking/atomic_notifier_chain_register_unique_prio() 2022-05-19 19:30:30 +02:00
nsproxy.c Revert "fs/exec: allow to unshare a time namespace on vfork+exec" 2022-09-13 10:38:43 -07:00
padata.c
panic.c kernel/panic: Drop unblank_screen call 2022-09-01 16:55:35 +02:00
params.c
pid_namespace.c kernel: pid_namespace: use NULL instead of using plain integer as pointer 2022-04-29 14:38:00 -07:00
pid.c gfs2: Add glockfd debugfs file 2022-06-29 13:07:16 +02:00
profile.c kernel/profile.c: simplify duplicated code in profile_setup() 2022-09-11 21:55:12 -07:00
ptrace.c freezer,sched: Rewrite core freezer logic 2022-09-07 21:53:50 +02:00
range.c
reboot.c kernel/reboot: Add SYS_OFF_MODE_RESTART_PREPARE mode 2022-10-04 15:59:36 +02:00
regset.c
relay.c relay: use kvcalloc to alloc page array in relay_alloc_page_array 2022-10-03 14:21:43 -07:00
resource_kunit.c
resource.c resource: Introduce alloc_free_mem_region() 2022-07-21 17:19:25 -07:00
rseq.c rseq: Use pr_warn_once() when deprecated/unknown ABI flags are encountered 2022-11-14 09:58:32 +01:00
scftorture.c
scs.c
seccomp.c seccomp: Add wait_killable semantic to seccomp user notifier 2022-05-03 14:11:58 -07:00
signal.c Scheduler changes for v6.1: 2022-10-10 09:10:28 -07:00
smp.c bitmap patches for v6.1-rc1 2022-10-10 12:49:34 -07:00
smpboot.c smpboot: use atomic_try_cmpxchg in cpu_wait_death and cpu_report_death 2022-09-11 21:55:10 -07:00
smpboot.h
softirq.c context_tracking: Take IRQ eqs entrypoints over RCU 2022-07-05 13:32:59 -07:00
stackleak.c stackleak: add on/off stack variants 2022-05-08 01:33:09 -07:00
stacktrace.c
static_call_inline.c
static_call.c
stop_machine.c Scheduler changes in this cycle were: 2022-05-24 11:11:13 -07:00
sys_ni.c kernel/sys_ni: add compat entry for fadvise64_64 2022-08-20 15:17:45 -07:00
sys.c Random number generator updates for Linux 6.1-rc1. 2022-10-10 10:41:21 -07:00
sysctl-test.c kernel/sysctl-test: use SYSCTL_{ZERO/ONE_HUNDRED} instead of i_{zero/one_hundred} 2022-09-08 16:56:45 -07:00
sysctl.c - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in 2022-10-10 17:53:04 -07:00
task_work.c task_work: use try_cmpxchg in task_work_add, task_work_cancel_match and task_work_run 2022-09-11 21:55:10 -07:00
taskstats.c genetlink: start to validate reserved header bytes 2022-08-29 12:47:15 +01:00
torture.c
tracepoint.c tracepoint: Optimize the critical region of mutex_lock in tracepoint_module_coming() 2022-09-26 13:01:18 -04:00
tsacct.c taskstats: version 12 with thread group and exe info 2022-04-29 14:38:03 -07:00
ucount.c ucounts: Split rlimit and ucount values and max values 2022-05-18 18:24:57 -05:00
uid16.c
uid16.h
umh.c freezer,sched: Rewrite core freezer logic 2022-09-07 21:53:50 +02:00
up.c
user_namespace.c ucounts: Split rlimit and ucount values and max values 2022-10-09 16:24:05 -07:00
user-return-notifier.c
user.c
usermode_driver.c blob_to_mnt(): kern_unmount() is needed to undo kern_mount() 2022-05-19 23:25:47 -04:00
utsname_sysctl.c kernel/utsname_sysctl.c: Fix hostname polling 2022-10-23 12:01:01 -07:00
utsname.c
watch_queue.c This was a moderately busy cycle for documentation, but nothing all that 2022-08-02 19:24:24 -07:00
watchdog_hld.c Revert "printk: add functions to prefer direct printing" 2022-06-23 18:41:40 +02:00
watchdog.c powerpc updates for 6.0 2022-08-06 16:38:17 -07:00
workqueue_internal.h
workqueue.c kcfi updates for v6.1-rc1 2022-10-03 17:11:07 -07:00