rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=8c14/1/0x4000000000000000 softirq=34873/34877 fqs=0
rcu: 	(detected by 1, t=10506 jiffies, g=26789, q=334 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9759 Comm: syz.4.1099 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_release+0x29a/0x3e0
Code: c7 db a5 ba 8d e8 66 ab dd 09 b8 ff ff ff ff 65 0f c1 05 09 a9 03 11 83 f8 01 75 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 <f7> 44 24 20 00 02 00 00 75 56 f7 c3 00 02 00 00 74 01 fb 65 48 8b
RSP: 0018:ffffc90000007818 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 0000000000000087 RCX: 4abd668d6862ca00
RDX: 0000000000000000 RSI: ffffffff8dbaa5db RDI: ffffffff8be34480
RBP: ffff888106e46130 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000000f00 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88804b027a98 R15: ffff888106e45640
FS:  00007f1df5b736c0(0000) GS:ffff8880b8611000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb2b6585493 CR3: 000000003e3ae000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000002 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 _raw_spin_unlock_irqrestore+0x70/0x110
 hrtimer_try_to_cancel+0x3be/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:__sanitizer_cov_trace_pc+0x4a/0x70
Code: 81 fa 00 01 00 00 75 35 83 b9 3c 16 00 00 00 74 2c 8b 91 18 16 00 00 83 fa 02 75 21 48 8b 91 20 16 00 00 48 8b 32 48 8d 7e 01 <8b> 89 1c 16 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 c3 cc cc
RSP: 0018:ffffc900028ffdb8 EFLAGS: 00000246
RAX: ffffffff8959aafd RBX: ffff888101684000 RCX: ffff888106e45640
RDX: ffffc90008d49000 RSI: 0000000000000033 RDI: 0000000000000034
RBP: 0000000000000106 R08: ffffc900028ffe80 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff8959aaf0 R12: dffffc0000000000
R13: 0000000000000000 R14: ffff888101684000 R15: ffffffff8959aaf0
 sock_alloc_inode+0xd/0xc0
 alloc_inode+0x6a/0x1b0
 __sock_create+0x12d/0x9f0
 __sys_socket+0xd7/0x1b0
 __x64_sys_socket+0x7a/0x90
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1df4d8ec29
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:00007f1df5b73038 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 00007f1df4fd5fa0 RCX: 00007f1df4d8ec29
RDX: 0000000000000106 RSI: 0200000000000001 RDI: 0000000000000002
RBP: 00007f1df4e11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1df4fd6038 R14: 00007f1df4fd5fa0 R15: 00007ffff131dc58
 </TASK>
rcu: rcu_preempt kthread starved for 10506 jiffies! g26789 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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  running task     stack:27224 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:
CPU: 1 UID: 0 PID: 9765 Comm: syz.2.1100 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:smp_call_function_many_cond+0xd33/0x12d0
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 b6 63 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 61 5f 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 45 5f
RSP: 0018:ffffc90002a3f2e0 EFLAGS: 00000293
RAX: ffffffff81b4665b RBX: 1ffff11009608341 RCX: ffff888107cf1cc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90002a3f460 R08: ffffffff8fa3b537 R09: 1ffffffff1f476a6
R10: dffffc0000000000 R11: fffffbfff1f476a7 R12: ffff88804b041a08
R13: dffffc0000000000 R14: ffff88813663b1c0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881a3c11000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000000df36000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80
 flush_tlb_mm_range+0x6b1/0x12d0
 tlb_flush_mmu+0x1a7/0x680
 tlb_finish_mmu+0xc3/0x1d0
 free_ldt_pgtables+0x17b/0x320
 exit_mmap+0x17c/0xb50
 __mmput+0x118/0x430
 exit_mm+0x1da/0x2c0
 do_exit+0x648/0x2300
 do_group_exit+0x21c/0x2d0
 get_signal+0x1286/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 exit_to_user_mode_loop+0x75/0x110
 ret_from_fork+0x4bc/0x7d0
 ret_from_fork_asm+0x1a/0x30
 </TASK>
