rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 ticks this GP) idle=f44c/1/0x40000002 softirq=23731/23731 fqs=1
rcu: 	(detected by 0, t=30002 jiffies, g=43093, q=4 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT 
Hardware name: ARM-Versatile Express
PC is at arch_spin_lock arch/arm/include/asm/spinlock.h:73 [inline]
PC is at do_raw_spin_lock include/linux/spinlock.h:187 [inline]
PC is at __raw_spin_lock include/linux/spinlock_api_smp.h:134 [inline]
PC is at _raw_spin_lock+0x4c/0x58 kernel/locking/spinlock.c:154
LR is at __raw_spin_lock include/linux/spinlock_api_smp.h:132 [inline]
LR is at _raw_spin_lock+0x18/0x58 kernel/locking/spinlock.c:154
pc : [<81abc000>]    lr : [<81abbfcc>]    psr: 80000113
sp : df805d68  ip : df805d68  fp : df805d7c
r10: 81c05450  r9 : 840eaa40  r8 : 83eab688
r7 : 840eab68  r6 : 00000000  r5 : 00000001  r4 : 840eab68
r3 : 000078da  r2 : 000078db  r1 : 00000000  r0 : 00000001
Flags: Nzcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 30c5387d  Table: 84cd5f80  DAC: 00000000
Call trace: frame pointer underflow
[<81abbfb4>] (_raw_spin_lock) from [<809c7b2c>] (class_raw_spinlock_constructor include/linux/spinlock.h:535 [inline])
[<81abbfb4>] (_raw_spin_lock) from [<809c7b2c>] (gpio_mmio_set+0x44/0x80 drivers/gpio/gpio-mmio.c:234)
 r5:00000001 r4:840eaa40
[<809c7ae8>] (gpio_mmio_set) from [<809b82e8>] (gpiochip_set+0x1c/0x44 drivers/gpio/gpiolib.c:2919)
 r7:00000000 r6:00000000 r5:00000000 r4:83ff8180
[<809b82cc>] (gpiochip_set) from [<809babb0>] (gpiod_set_raw_value_commit+0x78/0x218 drivers/gpio/gpiolib.c:3662)
[<809bab38>] (gpiod_set_raw_value_commit) from [<809bc450>] (gpiod_set_value_nocheck+0x44/0x58 drivers/gpio/gpiolib.c:3881)
 r10:81c05450 r9:df805ebc r8:00000102 r7:fffff2a8 r6:00000007 r5:00000000
 r4:83ff8180
[<809bc40c>] (gpiod_set_value_nocheck) from [<809bc4a0>] (gpiod_set_value+0x3c/0x88 drivers/gpio/gpiolib.c:3903)
[<809bc464>] (gpiod_set_value) from [<809ccc3c>] (gpio_led_set+0x5c/0x60 drivers/leds/leds-gpio.c:57)
 r5:83307044 r4:83307044
[<809ccbe0>] (gpio_led_set) from [<809ca4d4>] (__led_set_brightness drivers/leds/led-core.c:52 [inline])
[<809ccbe0>] (gpio_led_set) from [<809ca4d4>] (led_set_brightness_nopm drivers/leds/led-core.c:335 [inline])
[<809ccbe0>] (gpio_led_set) from [<809ca4d4>] (led_set_brightness_nosleep+0x38/0x44 drivers/leds/led-core.c:369)
 r5:83307044 r4:84e22ccc
[<809ca49c>] (led_set_brightness_nosleep) from [<809cd538>] (led_heartbeat_function+0x84/0x144 drivers/leds/trigger/ledtrig-heartbeat.c:90)
[<809cd4b4>] (led_heartbeat_function) from [<80327070>] (call_timer_fn+0x30/0x220 kernel/time/timer.c:1748)
 r7:fffff2a8 r6:809cd4b4 r5:84e22ccc r4:83216000
[<80327040>] (call_timer_fn) from [<80327524>] (expire_timers kernel/time/timer.c:1799 [inline])
[<80327040>] (call_timer_fn) from [<80327524>] (__run_timers+0x2c4/0x3f8 kernel/time/timer.c:2373)
 r9:df805ebc r8:fffff2a8 r7:00000000 r6:809cd4b4 r5:dddd9f00 r4:84e22ccc
[<80327260>] (__run_timers) from [<803276c0>] (__run_timer_base kernel/time/timer.c:2385 [inline])
[<80327260>] (__run_timers) from [<803276c0>] (__run_timer_base kernel/time/timer.c:2377 [inline])
[<80327260>] (__run_timers) from [<803276c0>] (run_timer_base+0x68/0x78 kernel/time/timer.c:2394)
 r10:83216000 r9:82804d80 r8:00000102 r7:00000001 r6:00000382 r5:00000002
 r4:dddd9f00
[<80327658>] (run_timer_base) from [<803276ec>] (run_timer_softirq+0x1c/0x34 kernel/time/timer.c:2404)
 r4:82804084
[<803276d0>] (run_timer_softirq) from [<8025b65c>] (handle_softirqs+0x140/0x458 kernel/softirq.c:622)
[<8025b51c>] (handle_softirqs) from [<8025bad0>] (__do_softirq kernel/softirq.c:656 [inline])
[<8025b51c>] (handle_softirqs) from [<8025bad0>] (invoke_softirq kernel/softirq.c:496 [inline])
[<8025b51c>] (handle_softirqs) from [<8025bad0>] (__irq_exit_rcu+0x110/0x1d0 kernel/softirq.c:723)
 r10:00000000 r9:83216000 r8:00000000 r7:df865e08 r6:82443f98 r5:8247f0cc
 r4:83216000
[<8025b9c0>] (__irq_exit_rcu) from [<8025be48>] (irq_exit+0x10/0x18 kernel/softirq.c:751)
 r5:8247f0cc r4:826c3a9c
[<8025be38>] (irq_exit) from [<81aada64>] (generic_handle_arch_irq+0x7c/0x80 kernel/irq/handle.c:295)
[<81aad9e8>] (generic_handle_arch_irq) from [<81a7da0c>] (call_with_stack+0x1c/0x20 arch/arm/lib/call_with_stack.S:40)
 r9:83216000 r8:83eab688 r7:df865e3c r6:ffffffff r5:60000113 r4:809c832c
[<81a7d9f0>] (call_with_stack) from [<80200bec>] (__irq_svc+0x8c/0xbc arch/arm/kernel/entry-armv.S:228)
Exception stack(0xdf865e08 to 0xdf865e50)
5e00:                   e0287008 00000009 000078da 00000000 e0287008 00000009
5e20: 00000001 840eab68 83eab688 840eaa40 00000000 df865e6c df865e58 df865e58
5e40: 809c8328 809c832c 60000113 ffffffff
[<809c830c>] (gpio_mmio_write32) from [<809c7b4c>] (gpio_mmio_set+0x64/0x80 drivers/gpio/gpio-mmio.c:241)
 r5:00000008 r4:840eaa40
[<809c7ae8>] (gpio_mmio_set) from [<809b82e8>] (gpiochip_set+0x1c/0x44 drivers/gpio/gpiolib.c:2919)
 r7:00000001 r6:00000000 r5:00000003 r4:83ff81bc
[<809b82cc>] (gpiochip_set) from [<809babb0>] (gpiod_set_raw_value_commit+0x78/0x218 drivers/gpio/gpiolib.c:3662)
[<809bab38>] (gpiod_set_raw_value_commit) from [<809bc450>] (gpiod_set_value_nocheck+0x44/0x58 drivers/gpio/gpiolib.c:3881)
 r10:00000000 r9:00000000 r8:00000001 r7:ddde24c0 r6:83330418 r5:00000001
 r4:83ff81bc
[<809bc40c>] (gpiod_set_value_nocheck) from [<809bc4a0>] (gpiod_set_value+0x3c/0x88 drivers/gpio/gpiolib.c:3903)
[<809bc464>] (gpiod_set_value) from [<809ccc3c>] (gpio_led_set+0x5c/0x60 drivers/leds/leds-gpio.c:57)
 r5:000000ff r4:83307314
[<809ccbe0>] (gpio_led_set) from [<809ca564>] (__led_set_brightness drivers/leds/led-core.c:52 [inline])
[<809ccbe0>] (gpio_led_set) from [<809ca564>] (led_set_brightness_nopm drivers/leds/led-core.c:335 [inline])
[<809ccbe0>] (gpio_led_set) from [<809ca564>] (led_set_brightness_nosleep drivers/leds/led-core.c:369 [inline])
[<809ccbe0>] (gpio_led_set) from [<809ca564>] (led_set_brightness+0x84/0x90 drivers/leds/led-core.c:328)
 r5:000000ff r4:83307314
[<809ca4e0>] (led_set_brightness) from [<809cc0e4>] (led_trigger_event drivers/leds/led-triggers.c:420 [inline])
[<809ca4e0>] (led_set_brightness) from [<809cc0e4>] (led_trigger_event+0x40/0x58 drivers/leds/led-triggers.c:408)
 r5:000000ff r4:83307314
[<809cc0a4>] (led_trigger_event) from [<809cd740>] (ledtrig_cpu+0xac/0xf4 drivers/leds/trigger/ledtrig-cpu.c:86)
 r7:ddde24c0 r6:00000002 r5:82b15cd8 r4:000000fe
[<809cd694>] (ledtrig_cpu) from [<80227a38>] (arch_cpu_idle_exit+0x14/0x18 arch/arm/kernel/process.c:98)
 r9:00000000 r8:00000001 r7:8280c710 r6:83216000 r5:8280c6d0 r4:00000001
[<80227a24>] (arch_cpu_idle_exit) from [<802b168c>] (do_idle+0x5c/0x2d8 kernel/sched/idle.c:334)
[<802b1630>] (do_idle) from [<802b1c38>] (cpu_startup_entry+0x30/0x34 kernel/sched/idle.c:430)
 r10:00000000 r9:414fc0f0 r8:80003000 r7:82a7b4a4 r6:83216000 r5:00000001
 r4:00000092
[<802b1c08>] (cpu_startup_entry) from [<8022f360>] (secondary_start_kernel+0x128/0x194 arch/arm/kernel/smp.c:478)
[<8022f238>] (secondary_start_kernel) from [<80220094>] (__enable_mmu+0x0/0xc arch/arm/kernel/head.S:446)
 r7:82a7b4a4 r6:30c0387d r5:00000000 r4:830b7bc0
rcu: rcu_preempt kthread starved for 30000 jiffies! g43093 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:0     pid:15    tgid:15    ppid:2      task_flags:0x208040 flags:0x00000000
Call trace: 
[<81ab123c>] (__schedule) from [<81ab24e8>] (__schedule_loop kernel/sched/core.c:6945 [inline])
[<81ab123c>] (__schedule) from [<81ab24e8>] (schedule+0x2c/0x130 kernel/sched/core.c:6960)
 r10:00000001 r9:828efccc r8:828efcd8 r7:83213000 r6:83213000 r5:82804d80
 r4:83213000
[<81ab24bc>] (schedule) from [<81abac60>] (schedule_timeout+0x8c/0x114 kernel/time/sleep_timeout.c:99)
 r5:82804d80 r4:fffff2a7
[<81ababd4>] (schedule_timeout) from [<80303f54>] (rcu_gp_fqs_loop+0x150/0x4cc kernel/rcu/tree.c:2083)
 r6:82804d80 r5:828efb00 r4:00000000
[<80303e04>] (rcu_gp_fqs_loop) from [<80308c00>] (rcu_gp_kthread+0xec/0x18c kernel/rcu/tree.c:2285)
 r10:df855f4c r9:82804d80 r8:828efb00 r7:828efcda r6:828efccc r5:828efcd8
 r4:83213000
[<80308b14>] (rcu_gp_kthread) from [<8027f6fc>] (kthread+0x12c/0x280 kernel/kthread.c:463)
 r7:830bf080
[<8027f5d0>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137)
Exception stack(0xdf855fb0 to 0xdf855ff8)
5fa0:                                     00000000 00000000 00000000 00000000
5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
5fe0: 00000000 00000000 00000000 00000000 00000013 00000000
 r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:8027f5d0
 r4:830b7c40