rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (3364 ticks this GP) idle=35e/1/0x4000000000000000 softirq=21400/21400 fqs=2682 
	(t=10500 jiffies g=33025 q=19453)
NMI backtrace for cpu 0
CPU: 0 PID: 13199 Comm: kworker/u4:5 Not tainted 5.14.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:342
 print_cpu_stall kernel/rcu/tree_stall.h:625 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:700 [inline]
 rcu_pending kernel/rcu/tree.c:3922 [inline]
 rcu_sched_clock_irq.cold+0x9f/0x747 kernel/rcu/tree.c:2641
 update_process_times+0x16d/0x200 kernel/time/timer.c:1782
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226
 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1421
 __run_hrtimer kernel/time/hrtimer.c:1537 [inline]
 __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1601
 hrtimer_interrupt+0x330/0xa00 kernel/time/hrtimer.c:1663
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline]
 __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1106
 sysvec_apic_timer_interrupt+0x40/0xc0 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x38/0x70 kernel/locking/spinlock.c:191
Code: 74 24 10 e8 8a a4 2e f8 48 89 ef e8 32 1a 2f f8 81 e3 00 02 00 00 75 25 9c 58 f6 c4 02 75 2d 48 85 db 74 01 fb bf 01 00 00 00 <e8> 13 f4 22 f8 65 8b 05 0c 90 d5 76 85 c0 74 0a 5b 5d c3 e8 30 4c
RSP: 0018:ffffc90000007b08 EFLAGS: 00000206
RAX: 0000000000000012 RBX: 0000000000000200 RCX: 1ffffffff1fa7ada
RDX: 0000000000000000 RSI: 0000000000000102 RDI: 0000000000000001
RBP: ffff8880219a8000 R08: 0000000000000001 R09: ffffffff8fcd09c7
R10: 0000000000000001 R11: ffffc90016f15000 R12: ffff888021ec8308
R13: ffff888146243400 R14: dffffc0000000000 R15: ffff888021ec8300
 spin_unlock_irqrestore include/linux/spinlock.h:409 [inline]
 dummy_timer+0x12f6/0x32b0 drivers/usb/gadget/udc/dummy_hcd.c:2001
 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1417
 expire_timers kernel/time/timer.c:1462 [inline]
 __run_timers.part.0+0x675/0xa50 kernel/time/timer.c:1731
 __run_timers kernel/time/timer.c:1712 [inline]
 run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1744
 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu+0x16e/0x1c0 kernel/softirq.c:636
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648
 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1100
 </IRQ>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:lock_release+0x3f1/0x720 kernel/locking/lockdep.c:5633
Code: 7e 83 f8 01 0f 85 8d 01 00 00 9c 58 f6 c4 02 0f 85 78 01 00 00 48 f7 04 24 00 02 00 00 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c5 48 c7 45 00 00 00 00 00 c7 45 08 00 00 00 00 48 8b 84 24
RSP: 0018:ffffc90017c379c0 EFLAGS: 00000206
RAX: dffffc0000000000 RBX: be0b11eb67c9c1a0 RCX: ffffc90017c37a10
RDX: 1ffff11004194bd4 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 1ffff92002f86f3a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000002 R14: ffff888020ca5ea8 R15: ffff888020ca54c0
 __raw_spin_unlock include/linux/spinlock_api_smp.h:150 [inline]
 _raw_spin_unlock+0x12/0x40 kernel/locking/spinlock.c:183
 spin_unlock include/linux/spinlock.h:394 [inline]
 zap_pte_range mm/memory.c:1422 [inline]
 zap_pmd_range mm/memory.c:1481 [inline]
 zap_pud_range mm/memory.c:1510 [inline]
 zap_p4d_range mm/memory.c:1531 [inline]
 unmap_page_range+0x1044/0x2a10 mm/memory.c:1552
 unmap_single_vma+0x198/0x300 mm/memory.c:1597
 unmap_vmas+0x16d/0x2f0 mm/memory.c:1629
 exit_mmap+0x1d0/0x620 mm/mmap.c:3201
 __mmput+0x122/0x470 kernel/fork.c:1101
 mmput+0x58/0x60 kernel/fork.c:1122
 free_bprm+0x65/0x2e0 fs/exec.c:1479
 kernel_execve+0x380/0x460 fs/exec.c:1976
 call_usermodehelper_exec_async+0x2e3/0x580 kernel/umh.c:112
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295