rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10499 ticks this GP) idle=d9a/1/0x4000000000000002 softirq=21926/21926 fqs=21 
	(t=10501 jiffies g=13097 q=188)
rcu: rcu_preempt kthread starved for 10459 jiffies! g13097 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29264    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3386 [inline]
 __schedule+0x934/0x1f90 kernel/sched/core.c:4082
 schedule+0xdc/0x2b0 kernel/sched/core.c:4156
 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1895
 rcu_gp_fqs_loop kernel/rcu/tree.c:1658 [inline]
 rcu_gp_kthread+0xa10/0x1940 kernel/rcu/tree.c:1818
 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: 10738 Comm: syz-executor.2 Not tainted 5.6.0-rc1-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:475 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:549 [inline]
 rcu_pending kernel/rcu/tree.c:3030 [inline]
 rcu_sched_clock_irq.cold+0x51a/0xc37 kernel/rcu/tree.c:2276
 update_process_times+0x2d/0x70 kernel/time/timer.c:1726
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:171
 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1314
 __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:1119 [inline]
 smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1144
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:check_memory_region+0x1f/0x1a0 mm/kasan/generic.c:191
Code: 00 66 2e 0f 1f 84 00 00 00 00 00 48 85 f6 0f 84 34 01 00 00 48 b8 ff ff ff ff ff 7f ff ff 55 0f b6 d2 48 39 c7 48 89 e5 41 55 <41> 54 53 0f 86 07 01 00 00 4c 8d 5c 37 ff 49 89 f8 48 b8 00 00 00
RSP: 0018:ffffc90007ea7108 EFLAGS: 00000212 ORIG_RAX: ffffffffffffff13
RAX: ffff7fffffffffff RBX: ffff88808fdbe690 RCX: ffffffff8206b083
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88808fdbe690
RBP: ffffc90007ea7110 R08: 0000000000000004 R09: fffff52000fd4e14
R10: fffff52000fd4e13 R11: 0000000000000003 R12: ffff888098958388
R13: 0000000000000002 R14: ffff88808fdbe848 R15: ffff8880579a9300
 __kasan_check_read+0x11/0x20 mm/kasan/common.c:95
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline]
 ext4_test_inode_state fs/ext4/ext4.h:1690 [inline]
 ext4_do_update_inode fs/ext4/inode.c:4926 [inline]
 ext4_mark_iloc_dirty+0x2b3/0x2ed0 fs/ext4/inode.c:5578
 ext4_mark_inode_dirty+0x255/0x9c0 fs/ext4/inode.c:5771
 ext4_dirty_inode+0xec/0x130 fs/ext4/inode.c:5802
 __mark_inode_dirty+0x68e/0x1390 fs/fs-writeback.c:2258
 mark_inode_dirty include/linux/fs.h:2183 [inline]
 generic_write_end+0x2fe/0x3e0 fs/buffer.c:2199
 ext4_da_write_end+0x209/0xb60 fs/ext4/inode.c:3092
 generic_perform_write+0x2fe/0x540 mm/filemap.c:3298
 ext4_buffered_write_iter+0x1fe/0x460 fs/ext4/file.c:270
 ext4_file_write_iter+0x1fe/0x14e0 fs/ext4/file.c:642
 call_write_iter include/linux/fs.h:1901 [inline]
 do_iter_readv_writev+0x5f8/0x8f0 fs/read_write.c:693
 do_iter_write fs/read_write.c:998 [inline]
 do_iter_write+0x184/0x610 fs/read_write.c:979
 vfs_iter_write+0x77/0xb0 fs/read_write.c:1039
 iter_file_splice_write+0x717/0xc10 fs/splice.c:760
 do_splice_from fs/splice.c:863 [inline]
 direct_splice_actor+0x123/0x190 fs/splice.c:1037
 splice_direct_to_actor+0x3b4/0xa30 fs/splice.c:992
 do_splice_direct+0x1da/0x2a0 fs/splice.c:1080
 do_sendfile+0x597/0xd00 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+0x15a/0x220 fs/read_write.c:1567
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45b3b9
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:00007f5e5b8e4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f5e5b8e56d4 RCX: 000000000045b3b9
RDX: 00000000200001c0 RSI: 0000000000000006 RDI: 0000000000000006
RBP: 000000000075c070 R08: 0000000000000000 R09: 0000000000000000
R10: 00008080fffffffe R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000008cb R14: 00000000004ca26f R15: 000000000075c07c