rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (0 ticks this GP) idle=f554/1/0x4000000000000000 softirq=17242/17242 fqs=0
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5852/1:b..l
rcu: 	(detected by 0, t=10506 jiffies, g=11713, q=701 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6607 Comm: syz.0.163 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:do_raw_spin_lock+0x125/0x290
Code: 00 00 c7 44 24 40 00 00 00 00 48 89 df be 04 00 00 00 e8 ee 2c 85 00 48 8d 7c 24 40 be 04 00 00 00 e8 df 2c 85 00 8b 44 24 40 <b9> 01 00 00 00 f0 0f b1 0b 0f 85 dd 00 00 00 65 8b 1d 69 bb 02 11
RSP: 0018:ffffc900001e07c0 EFLAGS: 00000097
RAX: 0000000000000000 RBX: ffff888136627a80 RCX: ffffffff819e14b1
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc900001e0800
RBP: ffffc900001e0870 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200003c100 R12: ffff888136627a90
R13: ffff888136627a88 R14: 1ffff11026cc4f52 R15: 1ffff11026cc4f51
FS:  00007f230d8066c0(0000) GS:ffff8881a3c13000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3b31d056c0 CR3: 000000010f926000 CR4: 00000000000006f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 _raw_spin_lock_irqsave+0xb3/0xf0
 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:ref_tracker_alloc+0x102/0x460
Code: ff e8 62 55 c0 fc 44 89 f0 25 11 00 40 00 4c 89 6c 24 08 0f 85 6e 02 00 00 e8 0a 51 c0 fc 31 c0 45 09 f4 41 81 cc 00 01 00 00 <48> 6b c0 70 4c 8d a8 78 36 be 8d 4c 89 e8 48 c1 e8 03 80 3c 18 00
RSP: 0018:ffffc9000623fbc0 EFLAGS: 00000206
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000080000
RDX: ffffc90003ca1000 RSI: 00000000000000ae RDI: 00000000000000af
RBP: ffffc9000623fd00 R08: ffff888021fe25af R09: 1ffff110043fc4b5
R10: dffffc0000000000 R11: ffffed10043fc4b6 R12: 000000000000adc0
R13: 1ffff92000c47f7c R14: 0000000000000cc0 R15: ffff88802fd7d500
 sk_alloc+0x1b1/0x370
 __netlink_create+0x65/0x260
 netlink_create+0x3ca/0x590
 __sock_create+0x4b3/0x9f0
 __sys_socket+0xd7/0x1b0
 __x64_sys_socket+0x7a/0x90
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f230c98eba9
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:00007f230d806038 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 00007f230cbd5fa0 RCX: 00007f230c98eba9
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000010
RBP: 00007f230ca11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f230cbd6038 R14: 00007f230cbd5fa0 R15: 00007fff18b02428
 </TASK>
task:syz-executor    state:R  running task     stack:21064 pid:5852  tgid:5852  ppid:5847   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
 _raw_spin_unlock+0x3f/0x50
 copy_pmd_range+0x68c6/0x71d0
 copy_page_range+0xc14/0x1270
 dup_mmap+0xf57/0x1ac0
 copy_mm+0x13c/0x4b0
 copy_process+0x1706/0x3c00
 kernel_clone+0x21e/0x840
 __x64_sys_clone+0x18b/0x1e0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3b30f85413
RSP: 002b:00007fff733dfe08 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3b30f85413
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 000055555995e7d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 00000000000162bb R15: 00007fff733dffa0
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g11713 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=3729
rcu: rcu_preempt kthread starved for 10506 jiffies! g11713 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:26632 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>
