rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10500 ticks this GP) idle=322/1/0x4000000000000002 softirq=441438/441447 fqs=2 
	(t=10502 jiffies g=570109 q=17562)
rcu: rcu_preempt kthread starved for 10499 jiffies! g570109 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    28776    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3385 [inline]
 __schedule+0x934/0x1f90 kernel/sched/core.c:4081
 schedule+0xdc/0x2b0 kernel/sched/core.c:4155
 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1895
 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline]
 rcu_gp_kthread+0x9b2/0x18d0 kernel/rcu/tree.c:1821
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 1
CPU: 1 PID: 31669 Comm: syz-executor.5 Not tainted 5.5.0-rc6-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+0x197/0x210 lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree_stall.h:254
 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:529 [inline]
 rcu_pending kernel/rcu/tree.c:2827 [inline]
 rcu_sched_clock_irq.cold+0x509/0xc0d kernel/rcu/tree.c:2271
 update_process_times+0x2d/0x70 kernel/time/timer.c:1726
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167
 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1310
 __run_hrtimer kernel/time/hrtimer.c:1517 [inline]
 __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1579
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1641
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:155 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x20/0x50 kernel/kcov.c:187
Code: 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 65 48 8b 04 25 c0 1e 02 00 65 8b 15 e4 28 8d 7e 81 e2 00 01 1f 00 48 8b 75 08 75 2b <8b> 90 80 13 00 00 83 fa 02 75 20 48 8b 88 88 13 00 00 8b 80 84 13
RSP: 0018:ffffc90001cc67d0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffff88808fd50100 RBX: ffffc90001cc68e8 RCX: ffffffff819248ba
RDX: 0000000000000000 RSI: ffffffff819248c4 RDI: 0000000000000005
RBP: ffffc90001cc67d0 R08: ffff88808fd50100 R09: fffff9400012c571
R10: fffff9400012c570 R11: ffffea0000962b87 R12: ffffea0000962b88
R13: 000000000017142e R14: ffffea0000962b80 R15: 0000000000000000
 __add_to_page_cache_locked+0x3b4/0xec0 mm/filemap.c:863
 add_to_page_cache_lru+0x1d8/0x790 mm/filemap.c:943
 ext4_mpage_readpages+0x46d/0x2220 fs/ext4/readpage.c:247
 ext4_readpages+0xe7/0x130 fs/ext4/inode.c:3244
 read_pages+0x108/0x610 mm/readahead.c:126
 __do_page_cache_readahead+0x4e0/0x5d0 mm/readahead.c:212
 ra_submit mm/internal.h:62 [inline]
 ondemand_readahead+0x55c/0xd30 mm/readahead.c:492
 page_cache_async_readahead mm/readahead.c:574 [inline]
 page_cache_async_readahead+0x437/0x7c0 mm/readahead.c:547
 generic_file_buffered_read mm/filemap.c:2059 [inline]
 generic_file_read_iter+0x13c0/0x2cf0 mm/filemap.c:2324
 ext4_file_read_iter fs/ext4/file.c:130 [inline]
 ext4_file_read_iter+0x1db/0x640 fs/ext4/file.c:113
 call_read_iter include/linux/fs.h:1896 [inline]
 new_sync_read+0x4d7/0x800 fs/read_write.c:414
 __vfs_read+0xe1/0x110 fs/read_write.c:427
 integrity_kernel_read+0x157/0x210 security/integrity/iint.c:200
 ima_calc_file_hash_tfm+0x2e3/0x3e0 security/integrity/ima/ima_crypto.c:360
 ima_calc_file_shash security/integrity/ima/ima_crypto.c:389 [inline]
 ima_calc_file_hash+0x1aa/0x570 security/integrity/ima/ima_crypto.c:454
 ima_collect_measurement+0x534/0x5f0 security/integrity/ima/ima_api.c:247
 process_measurement+0xd45/0x1850 security/integrity/ima/ima_main.c:326
 ima_file_check+0xc5/0x110 security/integrity/ima/ima_main.c:442
 do_last fs/namei.c:3424 [inline]
 path_openat+0x1138/0x4500 fs/namei.c:3537
 do_filp_open+0x1a1/0x280 fs/namei.c:3567
 do_sys_open+0x3fe/0x5d0 fs/open.c:1097
 __do_sys_open fs/open.c:1115 [inline]
 __se_sys_open fs/open.c:1110 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1110
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45af49
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:00007f2377daac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045af49
RDX: 0000000000000000 RSI: 0000000000141042 RDI: 0000000020000100
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2377dab6d4
R13: 00000000005006ff R14: 00000000004e0c48 R15: 00000000ffffffff