syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10499 ticks this GP) idle=6d1/1/0x4000000000000000 softirq=368975/368975 fqs=1 
	(t=10501 jiffies g=483337 q=1344)
rcu: rcu_preempt kthread starved for 10500 jiffies! g483337 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:
task:rcu_preempt     state:R  running task     stack:26576 pid:   14 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4972 [inline]
 __schedule+0xb72/0x1460 kernel/sched/core.c:6253
 schedule+0x12b/0x1f0 kernel/sched/core.c:6326
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1881
 rcu_gp_fqs_loop+0x1fd/0x770 kernel/rcu/tree.c:1955
 rcu_gp_kthread+0xa5/0x350 kernel/rcu/tree.c:2128
 kthread+0x468/0x490 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 12174 Comm: kworker/u4:3 Not tainted 5.16.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_many_cond+0xbc5/0xda0 kernel/smp.c:969
Code: 00 00 fc ff df 75 0e e8 09 b2 0b 00 eb 4c 0f 1f 80 00 00 00 00 f3 90 42 0f b6 04 3b 84 c0 75 11 41 f7 45 00 01 00 00 00 74 2b <e8> e6 b1 0b 00 eb e4 44 89 e9 80 e1 07 80 c1 03 38 c1 7c e2 4c 89
RSP: 0018:ffffc9000a877820 EFLAGS: 00000202
RAX: 0000000000000000 RBX: 1ffff1101734831d RCX: ffff888034e63a00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000a877960 R08: ffffffff8178d032 R09: ffffffff8442fcb0
R10: 0000000000000009 R11: ffff888034e63a00 R12: 0000000000000000
R13: ffff8880b9a418e8 R14: ffff8880b9b3a640 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb190c75718 CR3: 000000000c88e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1135
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:1112 [inline]
 text_poke_bp_batch+0x310/0x940 arch/x86/kernel/alternative.c:1297
 text_poke_flush arch/x86/kernel/alternative.c:1451 [inline]
 text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1458
 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x12d/0x250 kernel/jump_label.c:177
 static_key_enable+0x16/0x20 kernel/jump_label.c:190
 toggle_allocation_gate+0xbf/0x460 mm/kfence/core.c:733
 process_one_work+0x853/0x1140 kernel/workqueue.c:2298
 worker_thread+0xac1/0x1320 kernel/workqueue.c:2445
 kthread+0x468/0x490 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30
 </TASK>
NMI backtrace for cpu 0
CPU: 0 PID: 15398 Comm: syz-executor.1 Not tainted 5.16.0-rc8-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:88 [inline]
 dump_stack_lvl+0x1dc/0x2d8 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x45f/0x490 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x22d/0x390 kernel/rcu/tree_stall.h:343
 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:711 [inline]
 rcu_pending kernel/rcu/tree.c:3878 [inline]
 rcu_sched_clock_irq+0x1e33/0x2bc0 kernel/rcu/tree.c:2597
 update_process_times+0x197/0x200 kernel/time/timer.c:1785
 tick_sched_handle kernel/time/tick-sched.c:226 [inline]
 tick_sched_timer+0x27d/0x420 kernel/time/tick-sched.c:1428
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]
 __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103
 sysvec_apic_timer_interrupt+0x3e/0xb0 arch/x86/kernel/apic/apic.c:1097
 asm_sysvec_apic_timer_interrupt+0x12/0x20
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xd4/0x130 kernel/locking/spinlock.c:194
Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 92 b1 c1 f7 f6 44 24 21 02 75 4e 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 87 e2 4c f7 65 8b 05 d8 2b f5 75 85 c0 74 3f 48 c7 04 24 0e 36
RSP: 0018:ffffc90000007ac0 EFLAGS: 00000206
RAX: 73eddd79c6dce800 RBX: 1ffff92000000f5c RCX: ffffffff81667291
RDX: dffffc0000000000 RSI: 0000000000000102 RDI: 0000000000000001
RBP: ffffc90000007b48 R08: dffffc0000000000 R09: fffffbfff1ff3df9
R10: fffffbfff1ff3df9 R11: 0000000000000000 R12: dffffc0000000000
R13: 1ffff92000000f58 R14: ffffc90000007ae0 R15: 0000000000000246
 spin_unlock_irqrestore include/linux/spinlock.h:404 [inline]
 skb_dequeue+0x10e/0x140 net/core/skbuff.c:3216
 garp_queue_xmit net/802/garp.c:271 [inline]
 garp_join_timer+0x95/0x130 net/802/garp.c:423
 call_timer_fn+0xf6/0x210 kernel/time/timer.c:1421
 expire_timers kernel/time/timer.c:1466 [inline]
 __run_timers+0x71a/0x910 kernel/time/timer.c:1734
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1747
 __do_softirq+0x392/0x7a3 kernel/softirq.c:558
 __irq_exit_rcu+0xec/0x170 kernel/softirq.c:637
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:649
 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1097
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x12/0x20
RIP: 0010:finish_lock_switch+0x1c5/0x350 kernel/sched/core.c:4733
Code: be ff ff ff ff e8 fb 2a ae 08 85 c0 74 37 4d 85 e4 75 58 0f 1f 44 00 00 4c 89 ff e8 75 e2 b0 08 e8 b0 be 2e 00 fb 48 83 c4 10 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 0f 0b 4d 85 e4 0f 85 4a ff ff ff
RSP: 0018:ffffc900117a75e8 EFLAGS: 00000286
RAX: 73eddd79c6dce800 RBX: 1ffff11017347410 RCX: ffffffff81667291
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff8880b9a3a080 R08: dffffc0000000000 R09: fffffbfff1ff3df0
R10: fffffbfff1ff3df0 R11: 0000000000000000 R12: 0000000000000000
R13: ffff8880b9a3a318 R14: dffffc0000000000 R15: ffff8880b9a395c0
 finish_task_switch+0x140/0x630 kernel/sched/core.c:4850
 context_switch kernel/sched/core.c:4975 [inline]
 __schedule+0xb7a/0x1460 kernel/sched/core.c:6253
 preempt_schedule_common kernel/sched/core.c:6419 [inline]
 preempt_schedule+0x14d/0x190 kernel/sched/core.c:6444
 preempt_schedule_thunk+0x16/0x18
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:389 [inline]
 ext4_do_update_inode fs/ext4/inode.c:5095 [inline]
 ext4_mark_iloc_dirty+0x5f6/0x1ad0 fs/ext4/inode.c:5694
 __ext4_mark_inode_dirty+0x3f6/0x720 fs/ext4/inode.c:5890
 __ext4_unlink+0x9bb/0xb70 fs/ext4/namei.c:3183
 ext4_unlink+0x2eb/0x440 fs/ext4/namei.c:3231
 vfs_unlink+0x34d/0x690 fs/namei.c:4100
 do_unlinkat+0x4ee/0xa10 fs/namei.c:4167
 __do_sys_unlink fs/namei.c:4215 [inline]
 __se_sys_unlink fs/namei.c:4213 [inline]
 __x64_sys_unlink+0x45/0x50 fs/namei.c:4213
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fb192341e99
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb190c96168 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 00007fb192455030 RCX: 00007fb192341e99
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000140
RBP: 00007fb19239bff1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd4ecc5baf R14: 00007fb190c96300 R15: 0000000000022000
 </TASK>
----------------
Code disassembly (best guess), 4 bytes skipped:
   0:	df 75 0e             	fbstp  0xe(%rbp)
   3:	e8 09 b2 0b 00       	callq  0xbb211
   8:	eb 4c                	jmp    0x56
   a:	0f 1f 80 00 00 00 00 	nopl   0x0(%rax)
  11:	f3 90                	pause
  13:	42 0f b6 04 3b       	movzbl (%rbx,%r15,1),%eax
  18:	84 c0                	test   %al,%al
  1a:	75 11                	jne    0x2d
  1c:	41 f7 45 00 01 00 00 	testl  $0x1,0x0(%r13)
  23:	00
  24:	74 2b                	je     0x51
* 26:	e8 e6 b1 0b 00       	callq  0xbb211 <-- trapping instruction
  2b:	eb e4                	jmp    0x11
  2d:	44 89 e9             	mov    %r13d,%ecx
  30:	80 e1 07             	and    $0x7,%cl
  33:	80 c1 03             	add    $0x3,%cl
  36:	38 c1                	cmp    %al,%cl
  38:	7c e2                	jl     0x1c
  3a:	4c                   	rex.WR
  3b:	89                   	.byte 0x89