rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P19258/1:b..l P18587/1:b..l P8246/1:b..l
	(detected by 1, t=10502 jiffies, g=226801, q=42 ncpus=2)
task:kworker/u4:23   state:R  running task     stack:20864 pid:8246  ppid:2      flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870
 irqentry_exit+0x53/0x80 kernel/entry/common.c:433
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666
Code: 2b 00 74 08 4c 89 f7 e8 4f a2 77 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc900038af900 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff92000715f2c RCX: 1ffff92000715ecc
RDX: dffffc0000000000 RSI: ffffffff8aebf620 RDI: ffffffff8b3cf480
RBP: ffffc900038afa48 R08: dffffc0000000000 R09: fffffbfff2091e45
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000715f28
R13: dffffc0000000000 R14: ffffc900038af960 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:306 [inline]
 rcu_read_lock include/linux/rcupdate.h:747 [inline]
 inet_twsk_purge+0x164/0xb60 net/ipv4/inet_timewait_sock.c:295
 ops_exit_list net/core/net_namespace.c:174 [inline]
 cleanup_net+0x763/0xb60 net/core/net_namespace.c:601
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
task:kworker/u4:6    state:R  running task     stack:24888 pid:18587 ppid:2      flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870
 irqentry_exit+0x53/0x80 kernel/entry/common.c:433
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:debug_lockdep_rcu_enabled+0x25/0x30 kernel/rcu/update.c:281
Code: cc cc cc cc cc 31 c0 83 3d d7 72 e9 03 00 74 1d 83 3d 62 a6 e9 03 00 74 14 65 48 8b 0d f4 a1 78 75 31 c0 83 b9 dc 0a 00 00 00 <0f> 94 c0 c3 cc cc cc cc cc cc cc 48 8b 3c 24 e8 57 fb ff ff 66 90
RSP: 0018:ffffc90005d07bf0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff8880527ccb40 RCX: ffff888048afbb80
RDX: dffffc0000000000 RSI: ffffffff8aebf620 RDI: ffffffff8b3cf480
RBP: ffff888079628c08 R08: dffffc0000000000 R09: fffffbfff2091e45
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88807a380c80
R13: 0000000000000181 R14: ffff8880527ccb40 R15: dffffc0000000000
 rcu_read_lock include/linux/rcupdate.h:748 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
 batadv_nc_worker+0xf1/0x610 net/batman-adv/network-coding.c:719
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
task:syz-executor.1  state:R  running task     stack:27208 pid:19258 ppid:12051  flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870
 irqentry_exit+0x53/0x80 kernel/entry/common.c:433
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x60 kernel/kcov.c:206
Code: 00 0f 0b 0f 1f 00 53 48 89 fb e8 17 00 00 00 48 8b 3d 08 af e8 0c 48 89 de 5b e9 67 86 56 00 cc cc cc cc cc cc cc 48 8b 04 24 <65> 48 8b 0d 14 dd 77 7e 65 8b 15 15 dd 77 7e f7 c2 00 01 ff 00 74
RSP: 0018:ffffc9000b507618 EFLAGS: 00000286
RAX: ffffffff8a80db84 RBX: ffff88807d7fd480 RCX: ffff88807a0dd940
RDX: 0000000000000000 RSI: 000000000000000d RDI: 0000000000000007
RBP: ffffc9000b507810 R08: ffffffff8a80dab6 R09: ffffffff8a80d93b
R10: 0000000000000003 R11: ffff88807a0dd940 R12: 1ffff920016a0ee3
R13: ffffc9000b507718 R14: dffffc0000000000 R15: 000000000000000d
 mt_validate_nulls lib/maple_tree.c:7206 [inline]
 mt_validate+0x5364/0x5ad0 lib/maple_tree.c:7244
 validate_mm_mt+0x165/0x670 mm/mmap.c:295
 validate_mm+0x16e/0x380 mm/mmap.c:332
 mmap_region+0x19d2/0x1fa0 mm/mmap.c:2884
 do_mmap+0x8c5/0xf60 mm/mmap.c:1425
 vm_mmap_pgoff+0x1ca/0x2d0 mm/util.c:520
 ksys_mmap_pgoff+0x4f5/0x6d0 mm/mmap.c:1471
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fdbcd67cbe3
RSP: 002b:00007ffd5493c3b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 0000000000400000 RCX: 00007fdbcd67cbe3
RDX: 0000000000000003 RSI: 00000000003c0000 RDI: 0000001b2cb60000
RBP: 0000001b2cb60000 R08: 0000000000000004 R09: 0000000000040000
R10: 0000000000000011 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001
 </TASK>