rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P8701
rcu: 	(detected by 0, t=10502 jiffies, g=20441, q=87 ncpus=2)
task:syz.3.775       state:R  running task     stack:24248 pid:8701  tgid:8697  ppid:6543   task_flags:0x400140 flags:0x00004002
Call Trace:
 <TASK>
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10495 jiffies! g20441 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=6618
rcu: rcu_preempt kthread starved for 10496 jiffies! g20441 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26664 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_timeout+0x12b/0x270
 rcu_gp_fqs_loop+0x301/0x1540
 rcu_gp_kthread+0x99/0x390
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 ret_from_fork_asm+0x1a/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 UID: 0 PID: 8701 Comm: syz.3.775 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:hrtimer_cancel+0x33/0x50
Code: e8 42 15 12 00 48 89 df e8 9a f9 ff ff 89 c5 31 ff 89 c6 e8 6f 19 12 00 85 ed 78 0c e8 26 15 12 00 eb 1a e8 1f 15 12 00 f3 90 <48> 89 df e8 75 f9 ff ff 85 c0 78 ed 89 c5 e8 0a 15 12 00 89 e8 5b
RSP: 0018:ffffc900001e0990 EFLAGS: 00000006
RAX: ffffffff81ada9e1 RBX: ffff888023710de8 RCX: ffff8881098c8000
RDX: 0000000000010000 RSI: 0000000000000004 RDI: 00000000ffffffff
RBP: 00000000ffffffff R08: ffff888136627a83 R09: 1ffff11026cc4f50
R10: dffffc0000000000 R11: ffffed1026cc4f51 R12: ffff888023710e90
R13: dffffc0000000000 R14: ffff888023710de8 R15: ffffffffffff2fb9
FS:  00007f9535b7a6c0(0000) GS:ffff8881a3c15000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d419ff8 CR3: 00000000221e4000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000200000000300
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 cpu_clock_event_stop+0xd9/0x130
 __perf_event_overflow+0x580/0xe40
 perf_swevent_hrtimer+0x3c5/0x550
 __hrtimer_run_queues+0x4e0/0xc60
 hrtimer_interrupt+0x45b/0xaa0
 __sysvec_apic_timer_interrupt+0x10b/0x410
 sysvec_apic_timer_interrupt+0xa1/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:deref_stack_reg+0x1b3/0x230
Code: 39 f0 0f 96 c0 20 c8 3c 01 75 30 4c 89 c7 49 89 f7 e8 11 08 00 00 49 89 c6 48 8b 5c 24 18 48 89 d8 48 c1 e8 03 42 80 3c 38 00 <74> 08 48 89 df e8 d3 39 b0 00 4c 89 33 b0 01 eb 02 31 c0 48 83 c4
RSP: 0018:ffffc900091c6f00 EFLAGS: 00000246
RAX: 1ffff92001238e19 RBX: ffffc900091c70c8 RCX: 0000000000000001
RDX: ffffc900091c70c8 RSI: dffffc0000000000 RDI: ffffc900091c7110
RBP: 1ffff92001238e11 R08: ffffc900091c7110 R09: 0000000000000000
R10: ffffc900091c70d8 R11: fffff52001238e1d R12: 1ffff92001238e12
R13: 1ffff92001238e13 R14: ffffc900091c71b0 R15: dffffc0000000000
 unwind_next_frame+0x17c4/0x2390
 __unwind_start+0x5b9/0x760
 arch_stack_walk+0xe4/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5b/0x80
 kmem_cache_free+0x18f/0x400
 pppoe_rcv+0x470/0x740
 __netif_receive_skb_list_core+0x75a/0x800
 netif_receive_skb_list_internal+0x975/0xcc0
 netif_receive_skb_list+0x54/0x450
 bpf_test_run_xdp_live+0x1786/0x1b10
 bpf_prog_test_run_xdp+0x713/0x1000
 bpf_prog_test_run+0x2c7/0x340
 __sys_bpf+0x581/0x870
 __x64_sys_bpf+0x7c/0x90
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9534d8ec29
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9535b7a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f9534fd6090 RCX: 00007f9534d8ec29
RDX: 0000000000000050 RSI: 0000200000000600 RDI: 000000000000000a
RBP: 00007f9534e11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9534fd6128 R14: 00007f9534fd6090 R15: 00007ffdbf0d7d58
 </TASK>
