rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=3ca4/1/0x4000000000000000 softirq=32957/32958 fqs=50
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9857
rcu: 	(detected by 0, t=10503 jiffies, g=39529, q=279 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 9857 Comm: syz.0.967 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+0x694/0x2cf0
Code: 00 18 00 0f 84 bb 00 00 00 4c 89 f7 4c 89 ee ba 08 00 00 00 e8 8d 44 00 00 31 ed 85 c0 0f 84 19 0d 00 00 83 3d 4c 87 d5 18 00 <75> 13 48 63 44 24 20 48 0f a3 05 5d f7 d1 12 0f 83 62 1e 00 00 49
RSP: 0018:ffffc90000a08b20 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffff88802228a9f8 RCX: ffffffff9415b510
RDX: 0000000000000008 RSI: ffff88802228a9d8 RDI: ffff888022289dc0
RBP: 0000000000000000 R08: ffffffff84ded527 R09: 0000000000080000
R10: 0000000000000000 R11: ffffffff9a9e0cd8 R12: 0000000000000002
R13: ffff88802228a9d8 R14: ffff888022289dc0 R15: 0000000000000003
FS:  00007fb48d9d56c0(0000) GS:ffff8882a8f51000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb4855db000 CR3: 0000000012a50000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 lock_acquire+0x106/0x350
 _raw_spin_lock_irqsave+0x40/0x60
 debug_object_activate+0xb7/0x420
 enqueue_hrtimer+0xa9/0x2c0
 __hrtimer_run_queues+0x4ce/0xa10
 hrtimer_interrupt+0x448/0x910
 __sysvec_apic_timer_interrupt+0x102/0x430
 sysvec_apic_timer_interrupt+0xa1/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:finish_task_switch+0x417/0xc60
Code: 04 00 00 41 c7 84 24 20 0e 00 00 00 00 00 00 0f 1f 44 00 00 49 83 c4 48 4c 89 e7 e8 63 7a 3d 0a e8 8e a9 39 00 fb 4c 8b 65 c8 <49> 8d bc 24 f8 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0
RSP: 0018:ffffc90005917860 EFLAGS: 00000206
RAX: 00000000000033ff RBX: ffff88823c63bf20 RCX: 0000000080000001
RDX: 0000000000000007 RSI: ffffffff8e22c33a RDI: ffffffff8c4bda80
RBP: ffffc900059178b0 R08: ffffffff90578737 R09: 1ffffffff20af0e6
R10: dffffc0000000000 R11: fffffbfff20af0e7 R12: ffff888022289dc0
R13: ffff888022289dc0 R14: dffffc0000000000 R15: 1ffff110478c77e4
 __schedule+0x17e1/0x56c0
 preempt_schedule_irq+0x4d/0xa0
 irqentry_exit+0x14f/0x8f0
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:pte_offset_map_rw_nolock+0x87/0x160
Code: 48 c1 e8 03 42 80 3c 20 00 74 0c 48 c7 c7 10 1f 4f 8e e8 4c 29 14 00 4c 8b 2d 85 b4 2e 0c 4c 89 f8 48 c1 e8 03 42 80 3c 20 00 <74> 08 4c 89 ff e8 2f 29 14 00 4d 8b 3f 31 ff 4c 89 fe e8 b2 9b a6
RSP: 0000:ffffc90005917be8 EFLAGS: 00000246
RAX: 1ffff92000b22fa8 RBX: ffffc90005917dc0 RCX: 0000000000080000
RDX: ffffc90009f01000 RSI: 000000000002c744 RDI: 000000000002c745
RBP: ffffc90005917e58 R08: ffffffff822065c9 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8eb59c60 R12: dffffc0000000000
R13: ffffea0000000000 R14: ffff8881bcc5eed8 R15: ffffc90005917d40
 handle_mm_fault+0x1012/0x3080
 do_user_addr_fault+0xa4d/0x1340
 exc_page_fault+0x6a/0xc0
 asm_exc_page_fault+0x26/0x30
RIP: 0033:0x7fb48f6551d8
Code: 85 ed 74 3b 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 39 f0 72 1b 4d 8b 07 49 89 c1 49 29 f1 47 0f b6 0c 08 45 84 c9 74 08 <45> 88 0c 00 49 8b 47 10 48 83 c0 01 49 89 47 10 83 e9 01 73 d3 41
RSP: 002b:00007fb48d9d4470 EFLAGS: 00010282
RAX: 00000000001db000 RBX: 00007fb48d9d4530 RCX: 0000000000000016
RDX: 0000000000001dff RSI: 0000000000000200 RDI: 00007fb48d9d45d0
RBP: 00000000000000e8 R08: 00007fb485400000 R09: 00000000000000fe
R10: 0000200000033242 R11: 000000000000975f R12: 0000000000000181
R13: 00007fb48f853e00 R14: 0000000000000011 R15: 00007fb48d9d45d0
 </TASK>
task:syz.0.967       state:R  running task     stack:25704 pid:9857  tgid:9855  ppid:5618   task_flags:0x400040 flags:0x00080011
Call Trace:
 <TASK>
 </TASK>
rcu: rcu_preempt kthread starved for 10253 jiffies! g39529 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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  running task     stack:27496 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x17d9/0x56c0
 schedule+0x164/0x2b0
 schedule_timeout+0x152/0x2c0
 rcu_gp_fqs_loop+0x30c/0x11f0
 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: 0 UID: 0 PID: 8713 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:__sanitizer_cov_trace_pc+0x0/0x70
Code: 89 fb e8 23 00 00 00 48 8b 3d d4 ae 88 0c 48 89 de 5b e9 b3 08 62 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 48 8b 04 24 65 48 8b 0d 78 ee a5 11 65 8b 15 99 ee a5
RSP: 0018:ffffc90003dcf698 EFLAGS: 00000202
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff8881154f5940
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003dcf7c8 R08: ffffffff90578737 R09: 1ffffffff20af0e6
R10: dffffc0000000000 R11: fffffbfff20af0e7 R12: 1ffff110478c81d1
R13: ffff88812103c448 R14: ffff88823c640e88 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff88818d951000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f09123a7866 CR3: 000000000e946000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 smp_call_function_many_cond+0x10c7/0x14b0
 on_each_cpu_cond_mask+0x3f/0x80
 flush_tlb_mm_range+0x5c4/0x1090
 tlb_flush_mmu+0x1af/0xa30
 tlb_finish_mmu+0xf4/0x220
 free_ldt_pgtables+0x192/0x360
 exit_mmap+0x1bf/0x9f0
 __mmput+0x118/0x420
 exit_mm+0x221/0x2d0
 do_exit+0x6cd/0x2360
 do_group_exit+0x22d/0x2f0
 __x64_sys_exit_group+0x3f/0x40
 x64_sys_call+0x221a/0x2240
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0911efca90
Code: Unable to access opcode bytes at 0x7f0911efca66.
RSP: 002b:00007ffe81c4fc78 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0911efca90
RDX: 00000000000000e7 RSI: 000000000000003c RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000007 R09: 9ed30ca6cd0aade0
R10: 00000000ffffffff R11: 0000000000000202 R12: 000055cf917be950
R13: 00007ffe81c4fcb8 R14: 0000000000000001 R15: 000055cf917b4910
 </TASK>
