BUG: workqueue leaked atomic, lock or RCU: kworker/u8:7[957]
     preempt=0x00000000 lock=0->0 RCU=0->124 workfn=wb_workfn
CPU: 1 UID: 0 PID: 957 Comm: kworker/u8:7 Not tainted syzkaller #0 PREEMPT 
Hardware name: ARM-Versatile Express
Workqueue: writeback wb_workfn (flush-253:0)
Call trace: 
[<80201a14>] (dump_backtrace) from [<80201b08>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:60000013 r6:60000013 r5:8231c0d0 r4:00000000
[<80201af0>] (show_stack) from [<8021e320>] (__dump_stack lib/dump_stack.c:94 [inline])
[<80201af0>] (show_stack) from [<8021e320>] (dump_stack_lvl+0x5c/0x70 lib/dump_stack.c:120)
[<8021e2c4>] (dump_stack_lvl) from [<8021e34c>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r7:83012a00 r6:83801200 r5:84265554 r4:84127a00
[<8021e334>] (dump_stack) from [<802766a8>] (process_one_work+0x510/0x5a0 kernel/workqueue.c:3323)
[<80276198>] (process_one_work) from [<80277124>] (process_scheduled_works kernel/workqueue.c:3385 [inline])
[<80276198>] (process_one_work) from [<80277124>] (worker_thread+0x16c/0x318 kernel/workqueue.c:3466)
 r10:00000000 r9:84127a30 r8:833de200 r7:82a03d80 r6:83012a20 r5:83012a00
 r4:84127a00
[<80276fb8>] (worker_thread) from [<8028117c>] (kthread+0x11c/0x154 kernel/kthread.c:436)
 r10:00000000 r9:df849e88 r8:844da480 r7:84127a00 r6:80276fb8 r5:833de200
 r4:84131f40
[<80281060>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137)
Exception stack(0xe0449fb0 to 0xe0449ff8)
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 r5:80281060 r4:84131f40
------------[ cut here ]------------
WARNING: kernel/rcu/tree_plugin.h:332 at rcu_note_context_switch+0x4ac/0x638 kernel/rcu/tree_plugin.h:332, CPU#1: kworker/u8:7/957
Voluntary context switch within RCU read-side critical section!
Modules linked in: