INFO: task syz.5.12315:20772 blocked for more than 430 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.12315     state:D stack:0     pid:20772 tgid:20771 ppid:18211  task_flags:0x400040 flags:0x00000001
Call trace: 
[<81a38f54>] (__schedule) from [<80295c8c>] (__schedule_loop kernel/sched/core.c:7011 [inline])
[<81a38f54>] (__schedule) from [<80295c8c>] (rt_mutex_schedule+0x20/0x38 kernel/sched/core.c:7307)
 r10:841ac800 r9:00000002 r8:00000000 r7:df9b5da0 r6:df9b5da8 r5:855e6c00
 r4:855e6c00
[<80295c6c>] (rt_mutex_schedule) from [<81a3fdd0>] (rt_mutex_slowlock_block.constprop.0+0x40/0x1d4 kernel/locking/rtmutex.c:1647)
 r5:855e6c00 r4:833e5454
[<81a3fd90>] (rt_mutex_slowlock_block.constprop.0) from [<81a41128>] (__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline])
[<81a3fd90>] (rt_mutex_slowlock_block.constprop.0) from [<81a41128>] (__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline])
[<81a3fd90>] (rt_mutex_slowlock_block.constprop.0) from [<81a41128>] (rt_mutex_slowlock.constprop.0+0xd4/0x364 kernel/locking/rtmutex.c:1800)
 r10:60000013 r9:df9b5da8 r8:00000002 r7:df9b5da0 r6:833e5454 r5:00000000
 r4:855e6c00
[<81a41054>] (rt_mutex_slowlock.constprop.0) from [<81a4149c>] (__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline])
[<81a41054>] (rt_mutex_slowlock.constprop.0) from [<81a4149c>] (__rt_mutex_lock_common kernel/locking/rtmutex_api.c:49 [inline])
[<81a41054>] (rt_mutex_slowlock.constprop.0) from [<81a4149c>] (rt_mutex_lock+0x44/0x48 kernel/locking/rtmutex_api.c:89)
 r10:00000169 r9:00000001 r8:8615e000 r7:00000000 r6:df9b5e68 r5:00000001
 r4:833e5440
[<81a41458>] (rt_mutex_lock) from [<810e4a78>] (i2c_adapter_lock_bus+0x14/0x18 drivers/i2c/i2c-core-base.c:849)
[<810e4a64>] (i2c_adapter_lock_bus) from [<810e6854>] (i2c_lock_bus include/linux/i2c.h:809 [inline])
[<810e4a64>] (i2c_adapter_lock_bus) from [<810e6854>] (__i2c_lock_bus_helper drivers/i2c/i2c-core.h:46 [inline])
[<810e4a64>] (i2c_adapter_lock_bus) from [<810e6854>] (i2c_transfer+0x9c/0x110 drivers/i2c/i2c-core-base.c:2313)
[<810e67b8>] (i2c_transfer) from [<810e6924>] (i2c_transfer_buffer_flags+0x5c/0x8c drivers/i2c/i2c-core-base.c:2345)
 r6:00000000 r5:8615e000 r4:00001000
[<810e68c8>] (i2c_transfer_buffer_flags) from [<810ebc30>] (i2c_master_recv include/linux/i2c.h:79 [inline])
[<810e68c8>] (i2c_transfer_buffer_flags) from [<810ebc30>] (i2cdev_read+0x68/0x140 drivers/i2c/i2c-dev.c:155)
 r7:84b7a000 r6:85aa7b40 r5:20000500 r4:00001000
[<810ebbc8>] (i2cdev_read) from [<8055cd08>] (do_loop_readv_writev fs/read_write.c:847 [inline])
[<810ebbc8>] (i2cdev_read) from [<8055cd08>] (do_loop_readv_writev fs/read_write.c:835 [inline])
[<810ebbc8>] (i2cdev_read) from [<8055cd08>] (vfs_readv+0x224/0x290 fs/read_write.c:1020)
 r9:00000001 r8:00000001 r7:df9b5f88 r6:85aa7b40 r5:810ebbc8 r4:00000000
[<8055cae4>] (vfs_readv) from [<8055cf4c>] (do_preadv+0x90/0xf0 fs/read_write.c:1132)
 r9:855e6c00 r8:8020029c r7:20000180 r6:00000001 r5:85aa7b40 r4:85aa7b41
[<8055cebc>] (do_preadv) from [<8055f6b8>] (__do_sys_preadv fs/read_write.c:1179 [inline])
[<8055cebc>] (do_preadv) from [<8055f6b8>] (sys_preadv+0x20/0x28 fs/read_write.c:1174)
 r7:00000169 r6:00316310 r5:00000000 r4:00000009
[<8055f698>] (sys_preadv) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67)
Exception stack(0xdf9b5fa8 to 0xdf9b5ff0)
5fa0:                   00000009 00000000 00000003 20000180 00000001 00000005
5fc0: 00000009 00000000 00316310 00000169 00300000 00000000 00006364 76fb50bc
5fe0: 76fb4ec0 76fb4eb0 000195a4 00132510
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 32 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT 
Hardware name: ARM-Versatile Express
Call trace: 
[<80201a24>] (dump_backtrace) from [<80201b20>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:00000013 r5:60000093 r4:8224dfd0
[<80201b08>] (show_stack) from [<8021f91c>] (__dump_stack lib/dump_stack.c:94 [inline])
[<80201b08>] (show_stack) from [<8021f91c>] (dump_stack_lvl+0x70/0x7c lib/dump_stack.c:120)
[<8021f8ac>] (dump_stack_lvl) from [<8021f940>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r5:00000001 r4:00000001
[<8021f928>] (dump_stack) from [<81a22b6c>] (nmi_cpu_backtrace+0x160/0x17c lib/nmi_backtrace.c:113)
[<81a22a0c>] (nmi_cpu_backtrace) from [<81a22cb8>] (nmi_trigger_cpumask_backtrace+0x130/0x1d8 lib/nmi_backtrace.c:62)
 r7:00000001 r6:8280c690 r5:8281ae00 r4:ffffffff
[<81a22b88>] (nmi_trigger_cpumask_backtrace) from [<802304fc>] (arch_trigger_cpumask_backtrace+0x18/0x1c arch/arm/kernel/smp.c:852)
 r9:8281b9e8 r8:8280c810 r7:000e0880 r6:00007f0a r5:82abe7d4 r4:8616ef0c
[<802304e4>] (arch_trigger_cpumask_backtrace) from [<8037f2b4>] (trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline])
[<802304e4>] (arch_trigger_cpumask_backtrace) from [<8037f2b4>] (check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline])
[<802304e4>] (arch_trigger_cpumask_backtrace) from [<8037f2b4>] (watchdog+0x5d0/0x850 kernel/hung_task.c:495)
[<8037ece4>] (watchdog) from [<80280200>] (kthread+0x12c/0x280 kernel/kthread.c:463)
 r10:00000000 r9:00000000 r8:8037ece4 r7:8332a680 r6:8332a680 r5:83399800
 r4:00000001
[<802800d4>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137)
Exception stack(0xdf8e1fb0 to 0xdf8e1ff8)
1fa0:                                     00000000 00000000 00000000 00000000
1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
1fe0: 00000000 00000000 00000000 00000000 00000013 00000000
 r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:802800d4
 r4:832c4a00
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 2821 Comm: pr/ttyAMA-1 Not tainted syzkaller #0 PREEMPT 
Hardware name: ARM-Versatile Express
PC is at __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
PC is at _raw_spin_unlock_irqrestore+0x28/0x54 kernel/locking/spinlock.c:194
LR is at spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
LR is at __uart_port_unlock_irqrestore include/linux/serial_core.h:616 [inline]
LR is at pl011_console_device_unlock+0x20/0x24 drivers/tty/serial/amba-pl011.c:2603
pc : [<81a42f1c>]    lr : [<80a8d908>]    psr: 60000113
sp : eb741eb0  ip : eb741ec0  fp : eb741ebc
r10: 829594d4  r9 : 00000000  r8 : 00000000
r7 : 00000117  r6 : 82959438  r5 : 00000000  r4 : 00000001
r3 : 0000cb12  r2 : 00000000  r1 : 60000113  r0 : 84150040
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
Control: 30c5387d  Table: 861337c0  DAC: fffffffd
Call trace: 
[<81a42ef4>] (_raw_spin_unlock_irqrestore) from [<80a8d908>] (spin_unlock_irqrestore include/linux/spinlock.h:406 [inline])
[<81a42ef4>] (_raw_spin_unlock_irqrestore) from [<80a8d908>] (__uart_port_unlock_irqrestore include/linux/serial_core.h:616 [inline])
[<81a42ef4>] (_raw_spin_unlock_irqrestore) from [<80a8d908>] (pl011_console_device_unlock+0x20/0x24 drivers/tty/serial/amba-pl011.c:2603)
[<80a8d8e8>] (pl011_console_device_unlock) from [<802e3090>] (nbcon_emit_one+0x88/0x100 kernel/printk/nbcon.c:1142)
[<802e3008>] (nbcon_emit_one) from [<802e32b0>] (nbcon_kthread_func+0x1a8/0x2a4 kernel/printk/nbcon.c:1229)
 r6:8280c690 r5:83a98c00 r4:82959438
[<802e3108>] (nbcon_kthread_func) from [<80280200>] (kthread+0x12c/0x280 kernel/kthread.c:463)
 r10:00000000 r9:82959438 r8:802e3108 r7:84c67000 r6:84c67000 r5:83a98c00
 r4:00000001
[<802800d4>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137)
Exception stack(0xeb741fb0 to 0xeb741ff8)
1fa0:                                     00000000 00000000 00000000 00000000
1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
1fe0: 00000000 00000000 00000000 00000000 00000013 00000000
 r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:802800d4
 r4:83bd70c0