rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=f834/1/0x4000000000000000 softirq=352958/352958 fqs=0
rcu: 	(detected by 1, t=12947 jiffies, g=258881, q=13 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 2998 Comm: udevd 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:unwind_next_frame+0xd0e/0x2550
Code: c0 0f 85 c3 16 00 00 48 89 d8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 d9 16 00 00 48 0f bf 02 49 01 c4 48 8d 5e 01 48 8b 44 24 48 <0f> b6 04 28 84 c0 0f 85 40 12 00 00 49 89 df 49 c1 ef 03 41 0f b6
RSP: 0018:ffffc900000076d8 EFLAGS: 00000286
RAX: 1ffffffff21882b6 RBX: ffffffff90c415b3 RCX: ffffffff90489c50
RDX: ffffffff90c415ae RSI: ffffffff90c415b2 RDI: ffffffff8c28af00
RBP: dffffc0000000000 R08: 0000000000000005 R09: ffffffff8e95cd60
R10: ffffc90000007858 R11: fffff52000000f0d R12: ffffc900000078a0
R13: 1ffff92000000f01 R14: ffffc90000007808 R15: ffffc90000007840
FS:  0000000000000000(0000) GS:ffff88818dc8d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa7d7811866 CR3: 000000010cf5b000 CR4: 0000000000352ef0
Call Trace:
 <IRQ>
 __unwind_start+0x5b8/0x760
 arch_stack_walk+0xe3/0x150
 stack_trace_save+0xa9/0x100
 kasan_save_track+0x3e/0x80
 __kasan_mempool_unpoison_object+0xa3/0x130
 napi_skb_cache_get+0x3c8/0x780
 __alloc_skb+0x19a/0x7d0
 wg_packet_send_keepalive+0x65/0x2c0
 call_timer_fn+0x192/0x5e0
 __run_timer_base+0x652/0x8b0
 run_timer_softirq+0xb7/0x170
 handle_softirqs+0x22a/0x840
 __irq_exit_rcu+0xca/0x220
 irq_exit_rcu+0x9/0x30
 sysvec_apic_timer_interrupt+0xa6/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:unwind_next_frame+0x10e9/0x2550
Code: 84 c1 0f 84 b3 04 00 00 49 8d bf 80 00 00 00 e8 cd 20 00 00 48 89 c3 48 bd 00 00 00 00 00 fc ff df 48 8b 44 24 30 80 3c 28 00 <4c> 8b 6c 24 10 4d 89 fc 74 08 4c 89 ef e8 b5 fd b9 00 49 89 5d 00
RSP: 0018:ffffc90007127318 EFLAGS: 00000246
RAX: 1ffff92000e24e86 RBX: 00007fa7d72fca90 RCX: 1ffff92000e24e01
RDX: ffffffff90bc037a RSI: 0000000000000003 RDI: ffffc90007127fc8
RBP: dffffc0000000000 R08: 0000000000000022 R09: ffffffff8e95cd60
R10: ffffc90007127438 R11: ffffffff81b0ebd0 R12: 1ffff92000e24e7e
R13: ffffc90007120000 R14: ffffc900071273e8 R15: ffffc90007127f48
 arch_stack_walk+0x11b/0x150
 stack_trace_save+0xa9/0x100
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_cache_noprof+0x31c/0x660
 kmem_cache_free+0x156/0x650
 __put_anon_vma+0x12b/0x2d0
 unlink_anon_vmas+0x58b/0x730
 free_pgtables+0x836/0xb70
 exit_mmap+0x490/0x9e0
 __mmput+0x118/0x430
 exit_mm+0x18e/0x250
 do_exit+0x6a2/0x22c0
 do_group_exit+0x21b/0x2d0
 __x64_sys_exit_group+0x3f/0x40
 x64_sys_call+0x221a/0x2240
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa7d72fca90
Code: Unable to access opcode bytes at 0x7fa7d72fca66.
RSP: 002b:00007ffe37d2fc48 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa7d72fca90
RDX: 00000000000000e7 RSI: 000000000000003c RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000007 R09: a6a01352faf9cadf
R10: 00000000ffffffff R11: 0000000000000202 R12: 000055795ba22c60
R13: 00007ffe37d2fc88 R14: 0000000000000001 R15: 000055795b9ff910
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 12946 jiffies! g258881 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=58218
rcu: rcu_preempt kthread starved for 12973 jiffies! g258881 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200 ->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 stack:27536 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x1821/0x5740
 schedule+0x164/0x360
 schedule_timeout+0x158/0x2c0
 rcu_gp_fqs_loop+0x312/0x11d0
 rcu_gp_kthread+0x9e/0x2b0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 3859 Comm: syz.2.6104 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:vcpu_run+0x5a02/0x7860
Code: 4c 8b a4 24 28 01 00 00 4c 89 e3 48 c1 eb 03 42 0f b6 04 3b 84 c0 0f 85 1c 0b 00 00 41 c6 04 24 01 e8 32 ea 85 00 fb 4c 89 f0 <48> c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 5b fc e8 00 49 ff 06
RSP: 0018:ffffc90006ed75e0 EFLAGS: 00000206
RAX: ffff88816fe51d60 RBX: 1ffff1102dfca187 RCX: 0000000080000001
RDX: 0000000000000006 RSI: ffffffff8dfa6762 RDI: ffffffff8c28af60
RBP: ffffc90006ed79b0 R08: ffffffff9030b6f7 R09: 1ffffffff20616de
R10: dffffc0000000000 R11: fffffbfff20616df R12: ffff88816fe50c3a
R13: ffff88816fe50000 R14: ffff88816fe51d60 R15: dffffc0000000000
FS:  00007f45452b86c0(0000) GS:ffff8882a928d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000010e501000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000003e57 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 kvm_arch_vcpu_ioctl_run+0x11e6/0x20d0
 kvm_vcpu_ioctl+0xa62/0xfd0
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f454439cdd9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f45452b8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f4544615fa0 RCX: 00007f454439cdd9
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 000000000000000a
RBP: 00007f4544432d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4544616038 R14: 00007f4544615fa0 R15: 00007ffc68bc4798
 </TASK>
