rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 GPs behind) idle=776/1/0x4000000000000002 softirq=19247/19249 fqs=8 
	(t=10500 jiffies g=19785 q=193)
rcu: rcu_preempt kthread starved for 10482 jiffies! g19785 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    28848    10      2 0x80004000
Call Trace:
 schedule+0xd0/0x2a0 kernel/sched/core.c:4168
 schedule_timeout+0x35c/0x850 kernel/time/timer.c:1898
 rcu_gp_fqs_loop kernel/rcu/tree.c:1674 [inline]
 rcu_gp_kthread+0x9bf/0x1960 kernel/rcu/tree.c:1836
 kthread+0x388/0x470 kernel/kthread.c:268
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 1
CPU: 1 PID: 10040 Comm: syz-executor.5 Not tainted 5.6.0-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:77 [inline]
 dump_stack+0x188/0x20d lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x19b/0x1e5 kernel/rcu/tree_stall.h:254
 print_cpu_stall kernel/rcu/tree_stall.h:475 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:549 [inline]
 rcu_pending kernel/rcu/tree.c:3225 [inline]
 rcu_sched_clock_irq.cold+0x55d/0xcfa kernel/rcu/tree.c:2296
 update_process_times+0x25/0x60 kernel/time/timer.c:1727
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176
 tick_sched_timer+0x4e/0x140 kernel/time/tick-sched.c:1320
 __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
 __hrtimer_run_queues+0x3a2/0xf10 kernel/time/hrtimer.c:1583
 hrtimer_interrupt+0x312/0x770 kernel/time/hrtimer.c:1645
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1113 [inline]
 smp_apic_timer_interrupt+0x15b/0x600 arch/x86/kernel/apic/apic.c:1138
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:153 [inline]
RIP: 0010:write_comp_data+0x9/0x70 kernel/kcov.c:208
Code: 80 dc 13 00 00 48 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 c3 0f 1f 84 00 00 00 00 00 65 4c 8b 04 25 00 1f 02 00 <65> 8b 05 b8 2c 8f 7e a9 00 01 1f 00 75 51 41 8b 80 d8 13 00 00 83
RSP: 0018:ffffc9001714f1c0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000003 RBX: ffff88808140b93c RCX: ffffffff82006792
RDX: 0000000000000005 RSI: 000000000000000f RDI: 0000000000000005
RBP: ffff88808140b900 R08: ffff88805f1ee0c0 R09: ffffed10114dca33
R10: ffffed10114dca32 R11: ffff88808a6e5197 R12: ffff88808a6e5154
R13: 0000000000000005 R14: dffffc0000000000 R15: ffff88808a6e5378
 ext4_do_update_inode fs/ext4/inode.c:5008 [inline]
 ext4_mark_iloc_dirty+0x1372/0x2d70 fs/ext4/inode.c:5590
 ext4_mark_inode_dirty+0x225/0x900 fs/ext4/inode.c:5783
 ext4_dirty_inode+0xe7/0x120 fs/ext4/inode.c:5814
 __mark_inode_dirty+0x65e/0x1350 fs/fs-writeback.c:2258
 mark_inode_dirty include/linux/fs.h:2184 [inline]
 generic_write_end+0x2f4/0x3d0 fs/buffer.c:2193
 ext4_da_write_end+0x217/0xbd0 fs/ext4/inode.c:3092
 generic_perform_write+0x2c0/0x4e0 mm/filemap.c:3298
 ext4_buffered_write_iter+0x1f7/0x450 fs/ext4/file.c:270
 ext4_file_write_iter+0x1ec/0x13f0 fs/ext4/file.c:642
 call_write_iter include/linux/fs.h:1902 [inline]
 do_iter_readv_writev+0x5a8/0x850 fs/read_write.c:693
 do_iter_write fs/read_write.c:998 [inline]
 do_iter_write+0x18b/0x600 fs/read_write.c:979
 vfs_iter_write+0x70/0xa0 fs/read_write.c:1039
 iter_file_splice_write+0x684/0xb00 fs/splice.c:760
 do_splice_from fs/splice.c:863 [inline]
 direct_splice_actor+0x115/0x160 fs/splice.c:1037
 splice_direct_to_actor+0x38c/0x980 fs/splice.c:992
 do_splice_direct+0x1b4/0x280 fs/splice.c:1080
 do_sendfile+0x555/0xc50 fs/read_write.c:1520
 __do_sys_sendfile64 fs/read_write.c:1575 [inline]
 __se_sys_sendfile64 fs/read_write.c:1567 [inline]
 __x64_sys_sendfile64+0x149/0x210 fs/read_write.c:1567
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45c849
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f61df042c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f61df0436d4 RCX: 000000000045c849
RDX: 00000000200001c0 RSI: 0000000000000005 RDI: 0000000000000005
RBP: 000000000076c040 R08: 0000000000000000 R09: 0000000000000000
R10: 00008080fffffffe R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000008d4 R14: 00000000004cb786 R15: 000000000076c04c