rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 1, t=10502 jiffies, g=19165, q=424 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10499 (4294960530-4294950031), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread timer wakeup didn't happen for 10498 jiffies! g19165 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=8179
rcu: rcu_preempt kthread starved for 10499 jiffies! g19165 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200 ->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:R 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>
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: 7484 Comm: syz.8.354 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+0x97/0x290
Code: 4c 8d 77 04 4c 89 f0 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 9f 01 00 00 41 8b 06 3d ad 4e ad de 0f 85 1b 01 00 00 4c 8d 63 10 <4d> 89 e6 49 c1 ee 03 43 80 3c 3e 00 74 08 4c 89 e7 e8 93 ce 85 00
RSP: 0018:ffffc900000077c0 EFLAGS: 00000046
RAX: 00000000dead4ead RBX: ffff88804b027a80 RCX: 1ffff92000000efc
RDX: 0000000000000000 RSI: ffffffff8dbaa58c RDI: ffff88804b027a80
RBP: ffffc90000007870 R08: 0000000000000000 R09: ffffffff81adabcb
R10: ffffc900000075e0 R11: ffffffffa000080c R12: ffff88804b027a90
R13: ffff88804b027b00 R14: ffff88804b027a84 R15: dffffc0000000000
FS:  00007f6a1c44d6c0(0000) GS:ffff8880b8612000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000005000 CR3: 000000003d2f4000 CR4: 00000000000006f0
DR0: 0000000000000000 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:finish_task_switch+0x26b/0x950
Code: 0f 84 3c 01 00 00 48 85 db 0f 85 63 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 9f 70 ec 09 e8 ea 41 36 00 fb 4c 8b 65 c0 <49> 8d bc 24 18 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc90004ee67f8 EFLAGS: 00000282
RAX: 60e4d381d0dc3b00 RBX: 0000000000000000 RCX: 60e4d381d0dc3b00
RDX: 0000000000000007 RSI: ffffffff8d9baed8 RDI: ffffffff8be34400
RBP: ffffc90004ee6850 R08: ffffffff8fa3b537 R09: 1ffffffff1f476a6
R10: dffffc0000000000 R11: fffffbfff1f476a7 R12: ffff888021bf9cc0
R13: dffffc0000000000 R14: ffff888106d50000 R15: ffff88804b03b758
 __schedule+0x17a0/0x4cc0
 preempt_schedule_irq+0xb5/0x150
 irqentry_exit+0x6f/0x90
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:__kasan_check_byte+0x0/0x40
Code: 44 24 48 a8 01 0f 84 da fe ff ff 48 ff c8 49 89 c4 e9 cf fe ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <66> 0f 1f 00 41 56 53 48 89 f3 49 89 fe e8 5e 14 00 00 84 c0 75 16
RSP: 0018:ffffc90004ee6bf8 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 60e4d381d0dc3b00
RDX: ffffc90020caf000 RSI: ffffffff8b73817d RDI: ffffffff8e13a160
RBP: ffffffff8b73815c R08: ffffc90004ee6a0f R09: 0000000000000000
R10: ffffc90004ee6a00 R11: ffffffffa000080c R12: 0000000000000002
R13: ffffffff8e13a160 R14: 0000000000000000 R15: 0000000000000000
 lock_acquire+0x8d/0x360
 mt_find+0x17d/0x5f0
 find_vma+0xe7/0x160
 lock_mm_and_find_vma+0x5f/0x300
 do_user_addr_fault+0x331/0x1390
 exc_page_fault+0x76/0xf0
 asm_exc_page_fault+0x26/0x30
RIP: 0010:rep_movs_alternative+0x75/0x90
Code: 05 c3 cc cc cc cc 48 8b 06 48 89 07 48 8d 47 08 48 83 e0 f8 48 29 f8 48 01 c7 48 01 c6 48 29 c1 48 89 c8 48 c1 e9 03 83 e0 07 <f3> 48 a5 89 c1 85 c9 75 91 c3 cc cc cc cc 48 8d 0c c8 eb 86 cc cc
RSP: 0018:ffffc90004ee7058 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000578 RCX: 0000000000000050
RDX: 0000000000000001 RSI: 0000200000005000 RDI: ffff888038de2338
RBP: ffffc90004ee7210 R08: ffff888038de25b7 R09: 1ffff110071bc4b6
R10: dffffc0000000000 R11: ffffed10071bc4b7 R12: dffffc0000000000
R13: ffffc90004ee7e00 R14: ffff888038de2040 R15: 0000200000004d08
 _copy_from_user+0x7a/0xb0
 csum_and_copy_from_iter_full+0x4a1/0x1ed0
 ip_generic_getfrag+0x12f/0x2b0
 __ip6_append_data+0x30e7/0x3f30
 ip6_make_skb+0x2ce/0x410
 udpv6_sendmsg+0x1b78/0x24b0
 __sock_sendmsg+0xe5/0x270
 ____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: 0033:0x7f6a1b58ec29
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:00007f6a1c44d038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f6a1b7d5fa0 RCX: 00007f6a1b58ec29
RDX: 0000000000000000 RSI: 0000200000000380 RDI: 0000000000000007
RBP: 00007f6a1b611e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6a1b7d6038 R14: 00007f6a1b7d5fa0 R15: 00007fffc3a79618
 </TASK>
