rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5297/1:b..l P8042/1:b..l P8046/1:b..l P5696/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=21701, q=498 ncpus=2)
task:kworker/u8:2    state:R  running task     stack:24272 pid:5696  tgid:5696  ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 preempt_schedule_irq+0xb5/0x150
 irqentry_exit+0x6f/0x90
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:unwind_next_frame+0xc6d/0x2390
Code: 00 00 00 fc ff df 48 8b 44 24 30 80 3c 28 00 4c 8b 7c 24 18 74 08 4c 89 ff e8 8f 62 b0 00 49 89 1f 48 8b 44 24 58 80 3c 28 00 <48> 8b 5c 24 70 4c 8b 6c 24 50 4c 8b 64 24 10 74 08 48 89 df e8 6a
RSP: 0018:ffffc90002dff0f8 EFLAGS: 00000246
RAX: 1ffff920005bfe40 RBX: ffffffff8223057e RCX: 1ffff920005bfe01
RDX: ffffffff9037f164 RSI: 0000000000000002 RDI: ffffc90002dff308
RBP: dffffc0000000000 R08: 0000000000000007 R09: ffffffff8172d195
R10: ffffc90002dff218 R11: ffffffff81ac4d00 R12: ffffc90002e00000
R13: 1ffff920005bfe3b R14: ffffc90002dff1c8 R15: ffffc90002dff210
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_stack+0x3e/0x60
 kasan_record_aux_stack+0xbd/0xd0
 call_rcu+0x157/0x9c0
 kernfs_put+0x19e/0x480
 kernfs_remove_by_name_ns+0xb7/0x130
 sysfs_remove_group+0xfc/0x2c0
 sysfs_remove_groups+0x54/0xb0
 ib_free_port_attrs+0x281/0x3b0
 rdma_dev_exit_net+0x1d8/0x340
 ops_undo_list+0x49a/0x990
 cleanup_net+0x4c5/0x800
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30
 </TASK>
task:udevd           state:R  running task     stack:26280 pid:8046  tgid:8046  ppid:5297   task_flags:0x40014c flags:0x00004002
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
 unmap_page_range+0x3a79/0x4370
 unmap_vmas+0x399/0x580
 exit_mmap+0x248/0xb50
 __mmput+0x118/0x430
 exit_mm+0x1da/0x2c0
 do_exit+0x648/0x2300
 do_group_exit+0x21c/0x2d0
 __x64_sys_exit_group+0x3f/0x40
 x64_sys_call+0x21f7/0x2200
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0fd92fca90
RSP: 002b:00007ffde9ba6798 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0fd92fca90
RDX: 00000000000000e7 RSI: 000000000000003c RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000007 R09: ab09712836667bca
R10: 00000000ffffffff R11: 0000000000000202 R12: 000055913a10afb0
R13: 00007ffde9ba67d8 R14: 0000000000000001 R15: 000055913a0e4910
 </TASK>
task:udevd           state:R  running task     stack:27464 pid:8042  tgid:8042  ppid:5297   task_flags:0x40014c flags:0x00004002
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
 unmap_page_range+0x3a79/0x4370
 unmap_vmas+0x399/0x580
 exit_mmap+0x248/0xb50
 __mmput+0x118/0x430
 exit_mm+0x1da/0x2c0
 do_exit+0x648/0x2300
 do_group_exit+0x21c/0x2d0
 __x64_sys_exit_group+0x3f/0x40
 x64_sys_call+0x21f7/0x2200
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0fd92fca90
RSP: 002b:00007ffde9ba6798 EFLAGS: 00000206 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0fd92fca90
RDX: 00000000000000e7 RSI: 000000000000003c RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000007 R09: ab09712836667bca
R10: 00000000ffffffff R11: 0000000000000206 R12: 000055913a108330
R13: 00007ffde9ba67d8 R14: 0000000000000001 R15: 000055913a0e4910
 </TASK>
task:udevd           state:R  running task     stack:23208 pid:5297  tgid:5297  ppid:1      task_flags:0x400140 flags:0x00004002
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 preempt_schedule_irq+0xb5/0x150
 irqentry_exit+0x6f/0x90
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:lock_acquire+0x175/0x360
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 7b 5f 03 11 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc9000270f458 EFLAGS: 00000206
RAX: c4245daecfea6300 RBX: 0000000000000000 RCX: c4245daecfea6300
RDX: 0000000000000000 RSI: ffffffff8dba9eed RDI: ffffffff8be33e00
RBP: ffffffff8172d195 R08: 0000000000000000 R09: ffffffff8172d195
R10: ffffc9000270f618 R11: ffffffff81ac4d00 R12: 0000000000000002
R13: ffffffff8e13a120 R14: 0000000000000000 R15: 0000000000000246
 unwind_next_frame+0xc2/0x2390
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5b/0x80
 kfree+0x18e/0x440
 tomoyo_path_perm+0x3a2/0x4b0
 security_inode_getattr+0x12f/0x330
 vfs_statx+0x18e/0x550
 vfs_fstatat+0x118/0x170
 __x64_sys_newfstatat+0x116/0x190
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0fd93165f4
RSP: 002b:00007ffde9ba6878 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 000055913a0f4ce0 RCX: 00007f0fd93165f4
RDX: 00007ffde9ba6888 RSI: 0000559123e0f302 RDI: 00000000ffffff9c
RBP: 000055913a0e4910 R08: 00000000ffffffff R09: 7fffffffffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 0000559123e235e8
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10502 jiffies! g21701 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: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: 0 UID: 0 PID: 8047 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+0x11/0x70
Code: 5b e9 73 ac 58 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 0c 25 08 d0 a0 92 <65> 8b 15 18 0f e1 10 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75
RSP: 0000:ffffc90008587718 EFLAGS: 00000202
RAX: ffffffff81b4621b RBX: 1ffff11026cc7f61 RCX: ffff888105599cc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900085878a0 R08: ffffffff8fa3b537 R09: 1ffffffff1f476a6
R10: dffffc0000000000 R11: fffffbfff1f476a7 R12: ffff88813663fb08
R13: dffffc0000000000 R14: ffff88804b03b1c0 R15: 0000000000000001
FS:  00007f0fd96a4c80(0000) GS:ffff8880b8613000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055913a10c200 CR3: 0000000111970000 CR4: 00000000000006f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 smp_call_function_many_cond+0xd4b/0x12d0
 on_each_cpu_cond_mask+0x3f/0x80
 flush_tlb_mm_range+0x6b1/0x12d0
 ptep_clear_flush+0x120/0x170
 do_wp_page+0x1bc2/0x5800
 __handle_mm_fault+0x1033/0x5440
 handle_mm_fault+0x40a/0x8e0
 do_user_addr_fault+0xa81/0x1390
 exc_page_fault+0x76/0xf0
 asm_exc_page_fault+0x26/0x30
RIP: 0033:0x7f0fd92c744b
Code: 89 ef 4c 01 e3 e8 5f f5 ff ff eb 05 49 83 65 08 fe 49 8b 46 70 49 8d 56 60 48 8d 3d 72 e5 0e 00 48 39 50 18 0f 85 b8 fc ff ff <48> 89 45 10 48 89 55 18 48 81 fb ff 03 00 00 76 10 48 c7 45 20 00
RSP: 002b:00007ffde9ba66f0 EFLAGS: 00010246
RAX: 000055913a0e56c0 RBX: 000000000000ae90 RCX: 000055913a10e250
RDX: 00007f0fd93f1b00 RSI: 000055913a0e4010 RDI: 00007f0fd93b59b3
RBP: 000055913a10c1f0 R08: 0000000000000000 R09: ab09712836667bca
R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000008e30
R13: 000055913a10e250 R14: 00007f0fd93f1aa0 R15: 000055913a0e4910
 </TASK>
