rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (3694 ticks this GP) idle=b16/1/0x4000000000000000 softirq=38141/38141 fqs=0 
	(t=10501 jiffies g=57849 q=340)
rcu: rcu_preempt kthread starved for 9847 jiffies! g57849 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I29080    10      2 0x00004000
Call Trace:
 context_switch kernel/sched/core.c:3778 [inline]
 __schedule+0x8e5/0x21e0 kernel/sched/core.c:4527
 schedule+0xd0/0x2a0 kernel/sched/core.c:4602
 schedule_timeout+0x148/0x250 kernel/time/timer.c:1879
 rcu_gp_fqs_loop kernel/rcu/tree.c:1888 [inline]
 rcu_gp_kthread+0xae5/0x1b50 kernel/rcu/tree.c:2058
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
NMI backtrace for cpu 1
CPU: 1 PID: 18679 Comm: syz-executor.4 Not tainted 5.8.0-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+0x18f/0x20d lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x194/0x1cf kernel/rcu/tree_stall.h:318
 print_cpu_stall kernel/rcu/tree_stall.h:551 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:625 [inline]
 rcu_pending kernel/rcu/tree.c:3637 [inline]
 rcu_sched_clock_irq.cold+0x5b3/0xccd kernel/rcu/tree.c:2519
 update_process_times+0x25/0xa0 kernel/time/timer.c:1710
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176
 tick_sched_timer+0x1d1/0x2a0 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1524 [inline]
 __hrtimer_run_queues+0x1d5/0xfc0 kernel/time/hrtimer.c:1588
 hrtimer_interrupt+0x32a/0x930 kernel/time/hrtimer.c:1650
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0x142/0x5e0 arch/x86/kernel/apic/apic.c:1097
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 sysvec_apic_timer_interrupt+0xb2/0xf0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581
RIP: 0010:write_comp_data+0x2f/0x80 kernel/kcov.c:218
Code: 05 d6 bd 8d 7e 65 48 8b 34 25 00 ff 01 00 a9 00 01 ff 00 74 0f f6 c4 01 74 59 8b 86 0c 14 00 00 85 c0 74 4f 8b 86 e8 13 00 00 <83> f8 03 75 44 48 8b 86 f0 13 00 00 8b b6 ec 13 00 00 4c 8b 00 48
RSP: 0018:ffffc900061d7220 EFLAGS: 00000246
RAX: 0000000000000002 RBX: 0000000000000000 RCX: ffffffff81957a9a
RDX: 0000000000000000 RSI: ffff88804c924380 RDI: 0000000000000007
RBP: ffffea0001d8a5c8 R08: 0000000000000000 R09: ffffea0001d8a5c7
R10: 0000000000000000 R11: 0000000000000001 R12: ffffea0001d8a5c0
R13: ffffea0001d8a5c0 R14: dffffc0000000000 R15: ffffc900061d7278
 PageTransHuge include/linux/page-flags.h:614 [inline]
 hpage_nr_pages include/linux/huge_mm.h:270 [inline]
 find_subpage include/linux/pagemap.h:384 [inline]
 find_subpage include/linux/pagemap.h:378 [inline]
 find_get_entry+0x30a/0x8a0 mm/filemap.c:1590
 pagecache_get_page+0x47/0xf70 mm/filemap.c:1669
 grab_cache_page_write_begin+0x64/0x90 mm/filemap.c:3347
 ext4_da_write_begin+0x35c/0x11d0 fs/ext4/inode.c:2966
 generic_perform_write+0x20a/0x4f0 mm/filemap.c:3397
 ext4_buffered_write_iter+0x235/0x4a0 fs/ext4/file.c:270
 ext4_file_write_iter+0x1f3/0x1390 fs/ext4/file.c:657
 call_write_iter include/linux/fs.h:1872 [inline]
 do_iter_readv_writev+0x532/0x7b0 fs/read_write.c:713
 do_iter_write+0x188/0x670 fs/read_write.c:1018
 vfs_iter_write+0x70/0xa0 fs/read_write.c:1059
 iter_file_splice_write+0x721/0xbe0 fs/splice.c:750
 do_splice_from fs/splice.c:846 [inline]
 direct_splice_actor+0x171/0x2f0 fs/splice.c:1016
 splice_direct_to_actor+0x38c/0x980 fs/splice.c:971
 do_splice_direct+0x1b3/0x280 fs/splice.c:1059
 do_sendfile+0x55f/0xd40 fs/read_write.c:1540
 __do_sys_sendfile64 fs/read_write.c:1595 [inline]
 __se_sys_sendfile64 fs/read_write.c:1587 [inline]
 __x64_sys_sendfile64+0x149/0x210 fs/read_write.c:1587
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45ce69
Code: 2d 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 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f516bb9cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 0000000000026bc0 RCX: 000000000045ce69
RDX: 00000000200001c0 RSI: 0000000000000008 RDI: 0000000000000008
RBP: 000000000118bf68 R08: 0000000000000000 R09: 0000000000000000
R10: 00008080fffffffe R11: 0000000000000246 R12: 000000000118bf2c
R13: 00007ffcc753f07f R14: 00007f516bb9d9c0 R15: 000000000118bf2c