rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9550/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=27109, q=223 ncpus=2)
task:syz.3.1045      state:R  running task     stack:21816 pid:9550  tgid:9549  ppid:8894   task_flags:0x400140 flags:0x00004000
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 preempt_schedule_common+0x83/0xd0
 preempt_schedule+0xae/0xc0
 preempt_schedule_thunk+0x16/0x30
 __local_bh_enable_ip+0x13e/0x1c0
 bpf_test_run+0x376/0x7b0
 bpf_prog_test_run_skb+0xb30/0x1560
 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: 0033:0x7feed198eba9
RSP: 002b:00007feed2859038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007feed1bd5fa0 RCX: 00007feed198eba9
RDX: 0000000000000050 RSI: 0000200000001a00 RDI: 000000000000000a
RBP: 00007feed1a11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007feed1bd6038 R14: 00007feed1bd5fa0 R15: 00007ffefe1aece8
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10500 jiffies! g27109 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=11224
rcu: rcu_preempt kthread starved for 10501 jiffies! g27109 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
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:26728 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9551 Comm: syz.2.1044 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:__lock_acquire+0x840/0xd20
Code: 89 ca c1 c2 04 41 29 cc 44 31 e2 44 01 f9 41 29 d7 89 d6 c1 c6 06 44 31 fe 01 ca 89 f0 c1 c0 08 29 f1 31 c8 01 d6 29 c2 89 c1 <c1> c1 10 31 d1 01 f0 41 89 cf 41 c1 c7 13 29 ce 41 31 f7 01 c1 44
RSP: 0018:ffffc90000007750 EFLAGS: 00000012
RAX: 00000000ffe58d98 RBX: 0000000000000002 RCX: 00000000ffe58d98
RDX: 00000000001a71fd RSI: 00000000ffffe52c RDI: ffff8881070db980
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff81ada78b
R10: dffffc0000000000 R11: ffffed1009604f51 R12: 0000000000000068
R13: ffff8881070dc470 R14: ffff8881070dc4c0 R15: 0000000000000068
FS:  00007f26f77d86c0(0000) GS:ffff8880b8613000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d217ff8 CR3: 0000000031f7a000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000082 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 lock_acquire+0x120/0x360
 _raw_spin_lock_irqsave+0xa7/0xf0
 hrtimer_try_to_cancel+0x22b/0x420
 hrtimer_cancel+0x3b/0x50
 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:rcu_is_watching+0x69/0xb0
Code: e8 bc cc 7c 00 48 c7 c3 98 ff a1 92 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 34 8b 03 65 ff 0d d9 5d fa 10 74 11 <83> e0 04 c1 e8 02 5b 41 5e 41 5f c3 cc cc cc cc cc e8 e1 54 8d ff
RSP: 0018:ffffc9000310f398 EFLAGS: 00000286
RAX: 0000000000073f74 RBX: ffff88804b032f98 RCX: 18a5d4f05df83b00
RDX: 0000000000000000 RSI: ffffffff8be33de0 RDI: ffffffff8be33da0
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff8172d195
R10: ffffc9000310f4d8 R11: ffffffff81ac4d00 R12: 1ffff92000621e91
R13: ffffc9000310f4c0 R14: ffffffff8dbe2d10 R15: dffffc0000000000
 unwind_next_frame+0xd4/0x2390
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_track+0x3e/0x80
 __kasan_slab_alloc+0x6c/0x80
 kmem_cache_alloc_node_noprof+0x1bb/0x3c0
 kmalloc_reserve+0xbd/0x290
 __alloc_skb+0x142/0x2d0
 sock_wmalloc+0xb2/0x130
 l2tp_ip_sendmsg+0x1bb/0x1650
 __sock_sendmsg+0x19c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f26f698eba9
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:00007f26f77d8038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f26f6bd6090 RCX: 00007f26f698eba9
RDX: 000000000400c080 RSI: 0000200000000340 RDI: 000000000000000b
RBP: 00007f26f6a11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f26f6bd6128 R14: 00007f26f6bd6090 R15: 00007ffdae4fcd88
 </TASK>
