rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=c96/1/0x4000000000000000 softirq=129796/129796 fqs=1 
	(detected by 1, t=10502 jiffies, g=176825, q=29)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 24186 Comm: syz-executor.1 Not tainted 5.8.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:lookup_chain_cache kernel/locking/lockdep.c:3109 [inline]
RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3128 [inline]
RIP: 0010:validate_chain+0x133/0x8920 kernel/locking/lockdep.c:3183
Code: 19 eb 5f 0f 1f 40 00 48 8b 03 48 8d 58 f8 48 85 c0 48 0f 44 d8 48 85 db 74 48 4c 8d 63 18 4c 89 e0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 e7 e8 33 1f 59 00 49 8b 04 24 4c 39 f0 74 1c 48 83 c3
RSP: 0018:ffffc90000007910 EFLAGS: 00000046
RAX: 1ffffffff15beb81 RBX: ffffffff8adf5bf0 RCX: ffffffff815a8154
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8b3a74f0
RBP: ffffc90000007b00 R08: dffffc0000000000 R09: fffffbfff1674e9f
R10: fffffbfff1674e9f R11: 0000000000000000 R12: ffffffff8adf5c08
R13: ffff88805b928eb8 R14: 8165e272570ecded R15: dffffc0000000000
FS:  00007f2c84629700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004ec210 CR3: 00000000919c4000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __lock_acquire+0x116c/0x2c30 kernel/locking/lockdep.c:4380
 lock_acquire+0x160/0x720 kernel/locking/lockdep.c:4959
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x9e/0xc0 kernel/locking/spinlock.c:159
 debug_object_activate+0x62/0x5f0 lib/debugobjects.c:636
 debug_hrtimer_activate kernel/time/hrtimer.c:416 [inline]
 debug_activate kernel/time/hrtimer.c:476 [inline]
 enqueue_hrtimer kernel/time/hrtimer.c:965 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1537 [inline]
 __hrtimer_run_queues+0x510/0x930 kernel/time/hrtimer.c:1584
 hrtimer_interrupt+0x373/0xd60 kernel/time/hrtimer.c:1646
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0xf0/0x260 arch/x86/kernel/apic/apic.c:1097
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711
 </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+0xb9/0x130 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:585
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:770 [inline]
RIP: 0010:lock_acquire+0x1bf/0x720 kernel/locking/lockdep.c:4962
Code: c1 e8 03 80 3c 10 00 74 0c 48 c7 c7 f8 c7 4b 89 e8 c6 04 5a 00 48 83 3d 86 2b f2 07 00 0f 84 09 05 00 00 48 8b 7c 24 10 57 9d <0f> 1f 44 00 00 65 48 8b 04 25 28 00 00 00 48 3b 44 24 50 0f 85 e0
RSP: 0018:ffffc90006147818 EFLAGS: 00000282
RAX: 1ffffffff12978ff RBX: 0000000000000000 RCX: ffffffff815a8154
RDX: dffffc0000000000 RSI: 0000000000000008 RDI: 0000000000000282
RBP: 1ffff1100b7251b9 R08: dffffc0000000000 R09: fffffbfff1674eb0
R10: fffffbfff1674eb0 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: ffff88805b928dcc R15: 0000000000000000
 __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
 _raw_read_lock+0x2d/0x40 kernel/locking/spinlock.c:223
 ext4_es_lookup_extent+0x45/0x670 fs/ext4/extents_status.c:915
 ext4_da_map_blocks fs/ext4/inode.c:1698 [inline]
 ext4_da_get_block_prep+0x217/0x1190 fs/ext4/inode.c:1819
 ext4_block_write_begin+0x810/0x13f0 fs/ext4/inode.c:1061
 ext4_da_write_begin+0x71a/0xf80 fs/ext4/inode.c:2997
 generic_perform_write+0x23b/0x4e0 mm/filemap.c:3318
 ext4_buffered_write_iter+0x44d/0x5d0 fs/ext4/file.c:270
 ext4_file_write_iter+0x88d/0x1930 include/linux/fs.h:805
 call_write_iter include/linux/fs.h:1908 [inline]
 new_sync_write fs/read_write.c:503 [inline]
 vfs_write+0xa08/0xc70 fs/read_write.c:578
 ksys_write+0x11b/0x220 fs/read_write.c:631
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c369
Code: 8d 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 5b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f2c84628c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000000375c0 RCX: 000000000045c369
RDX: 0000000002d1ee37 RSI: 0000000020000180 RDI: 0000000000000003
RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007ffc867f0d5f R14: 00007f2c846299c0 R15: 000000000078bf0c
rcu: rcu_preempt kthread starved for 10500 jiffies! g176825 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    28896    10      2 0x00004000
Call Trace:
 context_switch kernel/sched/core.c:3458 [inline]
 __schedule+0x851/0xcf0 kernel/sched/core.c:4219