INFO: task syz.6.10417:16377 blocked for more than 430 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.10417     state:D stack:0     pid:16377 tgid:16148 ppid:12574  task_flags:0x400140 flags:0x00000001
Call trace: 
[<81b71894>] (__schedule) from [<81b72d2c>] (__schedule_loop kernel/sched/core.c:7311 [inline])
[<81b71894>] (__schedule) from [<81b72d2c>] (schedule+0x2c/0xec kernel/sched/core.c:7326)
 r10:831e9900 r9:876daaf0 r8:876da800 r7:82afcf80 r6:841624c0 r5:802c7394
 r4:841624c0
[<81b72d00>] (schedule) from [<80369bc0>] (cgroup_lock_and_drain_offline+0x180/0x214 kernel/cgroup/cgroup.c:3275)
 r5:802c7394 r4:ea79de3c
[<80369a40>] (cgroup_lock_and_drain_offline) from [<803730c0>] (cgroup1_get_tree+0x3c/0x4a4 kernel/cgroup/cgroup-v1.c:1265)
 r9:00000000 r8:8b81cf00 r7:00000400 r6:ea79df6c r5:831e9900 r4:00000008
[<80373084>] (cgroup1_get_tree) from [<805a3bb0>] (vfs_get_tree+0x2c/0x118 fs/super.c:1947)
 r10:831e9900 r9:00000000 r8:8b81cf00 r7:00000400 r6:ea79df6c r5:831e9900
 r4:00000008
[<805a3b84>] (vfs_get_tree) from [<805d1c20>] (fc_mount+0x14/0x7c fs/namespace.c:1198)
 r6:ea79df6c r5:831e9900 r4:00000008
[<805d1c0c>] (fc_mount) from [<805d7e64>] (do_new_mount_fc fs/namespace.c:3772 [inline])
[<805d1c0c>] (fc_mount) from [<805d7e64>] (do_new_mount fs/namespace.c:3848 [inline])
[<805d1c0c>] (fc_mount) from [<805d7e64>] (path_mount+0x424/0xb70 fs/namespace.c:4168)
 r5:00000000 r4:00000008
[<805d7a40>] (path_mount) from [<805d8d84>] (do_mount fs/namespace.c:4181 [inline])
[<805d7a40>] (path_mount) from [<805d8d84>] (__do_sys_mount fs/namespace.c:4397 [inline])
[<805d7a40>] (path_mount) from [<805d8d84>] (sys_mount+0x1dc/0x260 fs/namespace.c:4374)
 r10:00000015 r9:841624c0 r8:00000000 r7:00000000 r6:8b81cf00 r5:00000000
 r4:00000000
[<805d8ba8>] (sys_mount) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67)
Exception stack(0xea79dfa8 to 0xea79dff0)
dfa0:                   00000000 00000000 00000000 200000c0 20000000 00000400
dfc0: 00000000 00000000 00356458 00000015 00356418 00000000 00000001 76f9c0dc
dfe0: 76f9be88 76f9be78 00018fa0 00130a50
 r10:00000015 r9:841624c0 r8:8020029c r7:00000015 r6:00356458 r5:00000000
 r4:00000000
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 29 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: ARM-Versatile Express
Call trace: 
[<80201998>] (dump_backtrace) from [<80201a8c>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:60000093 r6:60000093 r5:82336570 r4:00000000
[<80201a74>] (show_stack) from [<8021ec68>] (__dump_stack lib/dump_stack.c:94 [inline])
[<80201a74>] (show_stack) from [<8021ec68>] (dump_stack_lvl+0x5c/0x70 lib/dump_stack.c:120)
[<8021ec0c>] (dump_stack_lvl) from [<8021ec94>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r7:00000000 r6:00000013 r5:00000000 r4:00000001
[<8021ec7c>] (dump_stack) from [<81b5aefc>] (nmi_cpu_backtrace+0x150/0x170 lib/nmi_backtrace.c:122)
[<81b5adac>] (nmi_cpu_backtrace) from [<81b5b050>] (nmi_trigger_cpumask_backtrace+0x134/0x208 lib/nmi_backtrace.c:65)
 r7:82a0b150 r6:83800000 r5:82a1c7b8 r4:ffffffff
[<81b5af1c>] (nmi_trigger_cpumask_backtrace) from [<802300d4>] (arch_trigger_cpumask_backtrace+0x18/0x1c arch/arm/kernel/smp.c:851)
 r9:82a0b2f0 r8:00000001 r7:82a1ce80 r6:82ccce2c r5:00007edf r4:00000048
[<802300bc>] (arch_trigger_cpumask_backtrace) from [<81b62b8c>] (trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline])
[<802300bc>] (arch_trigger_cpumask_backtrace) from [<81b62b8c>] (__sys_info lib/sys_info.c:157 [inline])
[<802300bc>] (arch_trigger_cpumask_backtrace) from [<81b62b8c>] (sys_info+0x68/0xa8 lib/sys_info.c:165)
[<81b62b24>] (sys_info) from [<80390a60>] (check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline])
[<81b62b24>] (sys_info) from [<80390a60>] (watchdog+0x3a0/0x848 kernel/hung_task.c:561)
 r5:00007edf r4:0000000a
[<803906c0>] (watchdog) from [<802827b4>] (kthread+0x11c/0x154 kernel/kthread.c:436)
 r10:00000000 r9:df819e60 r8:83113780 r7:00000000 r6:803906c0 r5:83800000
 r4:8387e000
[<80282698>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137)
Exception stack(0xdf8d5fb0 to 0xdf8d5ff8)
5fa0:                                     00000000 00000000 00000000 00000000
5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
5fe0: 00000000 00000000 00000000 00000000 00000013 00000000
 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:80282698 r4:8387e000
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 2829 Comm: pr/ttyAMA-1 Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: ARM-Versatile Express
PC is at __this_cpu_preempt_check+0x0/0x24 lib/smp_processor_id.c:63
LR is at kstat_incr_softirqs_this_cpu include/linux/kernel_stat.h:69 [inline]
LR is at handle_softirqs+0x130/0x4e4 kernel/softirq.c:619
pc : [<81b6ebe4>]    lr : [<8025b17c>]    psr: 200f0113
sp : df805f30  ip : df805ec0  fp : df805fac
r10: 8413ee40  r9 : 00000080  r8 : 00000101
r7 : 00000024  r6 : 00000008  r5 : 00000001  r4 : 82a030a4
r3 : 82a03080  r2 : 00000000  r1 : 00000000  r0 : 82516e2c
Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 30c5387d  Table: 857c3a80  DAC: 00000000
Call trace: frame pointer underflow
[<8025b04c>] (handle_softirqs) from [<8025b6cc>] (__do_softirq kernel/softirq.c:656 [inline])
[<8025b04c>] (handle_softirqs) from [<8025b6cc>] (invoke_softirq kernel/softirq.c:496 [inline])
[<8025b04c>] (handle_softirqs) from [<8025b6cc>] (__irq_exit_rcu+0x150/0x1d0 kernel/softirq.c:735)
 r10:82b5e31c r9:8413ee40 r8:00000000 r7:eb489e78 r6:824ea5cc r5:82525dfc
 r4:8413ee40
[<8025b57c>] (__irq_exit_rcu) from [<8025ba04>] (irq_exit+0x10/0x18 kernel/softirq.c:764)
 r5:82525dfc r4:828d3f6c
[<8025b9f4>] (irq_exit) from [<81b6df3c>] (generic_handle_arch_irq+0x7c/0x80 kernel/irq/handle.c:293)
[<81b6dec0>] (generic_handle_arch_irq) from [<81b3abc8>] (call_with_stack+0x1c/0x20 arch/arm/lib/call_with_stack.S:40)
 r9:8413ee40 r8:00000000 r7:eb489eac r6:ffffffff r5:600f0113 r4:81b7c1f4
[<81b3abac>] (call_with_stack) from [<80200bec>] (__irq_svc+0x8c/0xbc arch/arm/kernel/entry-armv.S:228)
Exception stack(0xeb489e78 to 0xeb489ec0)
9e60:                                                       8455c040 600f0113
9e80: 00000000 00005f41 00000001 00000000 82b5e280 00000117 00000000 00000001
9ea0: 82b5e31c eb489ed4 eb489ed8 eb489ec8 80b0d95c 81b7c1f4 600f0113 ffffffff
[<81b7c1cc>] (_raw_spin_unlock_irqrestore) from [<80b0d95c>] (spin_unlock_irqrestore include/linux/spinlock.h:408 [inline])
[<81b7c1cc>] (_raw_spin_unlock_irqrestore) from [<80b0d95c>] (__uart_port_unlock_irqrestore include/linux/serial_core.h:618 [inline])
[<81b7c1cc>] (_raw_spin_unlock_irqrestore) from [<80b0d95c>] (pl011_console_device_unlock+0x20/0x24 drivers/tty/serial/amba-pl011.c:2720)
[<80b0d93c>] (pl011_console_device_unlock) from [<802ed2c8>] (nbcon_emit_one+0x88/0x100 kernel/printk/nbcon.c:1165)
[<802ed240>] (nbcon_emit_one) from [<802ed548>] (nbcon_kthread_func+0x208/0x2ec kernel/printk/nbcon.c:1271)
 r6:82cc92ec r5:82b5e280 r4:8413ee40
[<802ed340>] (nbcon_kthread_func) from [<802827b4>] (kthread+0x11c/0x154 kernel/kthread.c:436)
 r10:00000000 r9:df8f5b38 r8:84795900 r7:82b5e280 r6:802ed340 r5:8413ee40
 r4:838b4840
[<80282698>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137)
Exception stack(0xeb489fb0 to 0xeb489ff8)
9fa0:                                     00000000 00000000 00000000 00000000
9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
9fe0: 00000000 00000000 00000000 00000000 00000013 00000000
 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:80282698 r4:838b4840