[v5.15] INFO: rcu detected stall in sync_hw_clock

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Jan 4, 2024, 7:38:21 AMJan 4
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Hello,

syzbot found the following issue on:

HEAD commit: d93fa2c78854 Linux 5.15.145
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17c917f6e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=68cb856f08cf8214
dashboard link: https://syzkaller.appspot.com/bug?extid=7d6bde386482547466a4
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17b6e845e80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=136e4091e80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2fdac32b009c/disk-d93fa2c7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5c99dfaee802/vmlinux-d93fa2c7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/52e4895d11f6/bzImage-d93fa2c7.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7d6bde...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
(detected by 1, t=10502 jiffies, g=3689, q=151)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294966185-4294955683), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10502 jiffies! g3689 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:27000 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
schedule+0x11b/0x1f0 kernel/sched/core.c:6459
schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1884
rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972
rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 13 Comm: kworker/0:1 Not tainted 5.15.145-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Workqueue: events_freezable_power_ sync_hw_clock
RIP: 0010:lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
Code: 41 0f 94 c1 48 8b 7c 24 20 44 89 f6 8b 54 24 1c 48 8b 4c 24 30 4c 8b 44 24 38 6a 00 6a 00 ff 75 10 ff 74 24 40 e8 55 04 00 00 <48> 83 c4 20 48 c7 c7 20 22 8b 8a e8 b5 8d b9 08 b8 ff ff ff ff 65
RSP: 0018:ffffc90000007ac0 EFLAGS: 00000086
RAX: 0000000000000001 RBX: ffffc90000007b40 RCX: ffffffff81633742
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffffffff8fbcf0c0
RBP: ffffc90000007c28 R08: dffffc0000000000 R09: fffffbfff1f79e19
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000000f64
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000046
FS: 0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000600 CR3: 000000001d32a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<IRQ>
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
debug_object_deactivate+0x61/0x3f0 lib/debugobjects.c:759
debug_hrtimer_deactivate kernel/time/hrtimer.c:425 [inline]
debug_deactivate+0x1b/0x1e0 kernel/time/hrtimer.c:481
__run_hrtimer kernel/time/hrtimer.c:1653 [inline]
__hrtimer_run_queues+0x31d/0xcf0 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline]
__sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102
sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1096
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:raw_spin_rq_unlock_irq+0x19/0x80 kernel/sched/sched.h:1339
Code: 38 c1 7c cb 4c 89 f7 e8 25 79 70 00 eb c1 0f 1f 00 41 57 41 56 53 48 89 fb 66 90 48 89 df e8 7e 14 cc 08 e8 59 3e 2d 00 fb 5b <41> 5e 41 5f c3 49 bf 00 00 00 00 00 fc ff df 4c 8d b3 58 0d 00 00
RSP: 0018:ffffc90000d27788 EFLAGS: 00000282
RAX: 9e7f07506b184b00 RBX: ffff8880b9a39700 RCX: ffffffff8162eb78
RDX: dffffc0000000000 RSI: ffffffff8a8b0f80 RDI: ffffffff8ad88080
RBP: ffffc90000d27970 R08: dffffc0000000000 R09: fffffbfff1f79e35
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88813fe20000
R13: dffffc0000000000 R14: ffff88813fe20000 R15: ffff88813fe20080
__schedule+0x1462/0x45b0 kernel/sched/core.c:6382
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6552
preempt_schedule+0xd9/0xe0 kernel/sched/core.c:6577
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
_raw_spin_unlock_irqrestore+0x128/0x130 kernel/locking/spinlock.c:194
hrtimer_start include/linux/hrtimer.h:418 [inline]
sched_sync_hw_clock kernel/time/ntp.c:519 [inline]
sync_hw_clock+0x418/0x520 kernel/time/ntp.c:660
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
</TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.351 msecs


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