syzbot

general protection fault, probably for non-canonical address 0xdffffc000000004b: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000258-0x000000000000025f]
CPU: 0 PID: 15597 Comm: kworker/u4:11 Not tainted 5.9.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
RIP: 0010:dst_dev_put+0x1d/0x220 net/core/dst.c:156
Code: cc cc cc cc cc cc cc cc cc cc cc cc cc 41 54 55 53 48 89 fb e8 24 79 07 fb 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 8b 01 00 00 48 8d 7b 3a 4c 8b 23 48 b8 00 00 00
RSP: 0018:ffffc90000007d78 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000258 RCX: ffffffff86f86f45
RDX: 000000000000004b RSI: ffffffff866ec51c RDI: 0000000000000258
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8d0c09ff
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000007
R13: fffffbfff16b2cfc R14: 0000607f518d0058 R15: 0000000000000258
FS:  0000000000000000(0000) GS:ffff8880ae400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff0687f7ab4 CR3: 0000000009e8d000 CR4: 00000000001526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 rt_fibinfo_free_cpus.part.0+0xda/0x140 net/ipv4/fib_semantics.c:202
 rt_fibinfo_free_cpus net/ipv4/fib_semantics.c:194 [inline]
 fib_nh_common_release+0xff/0x330 net/ipv4/fib_semantics.c:215
 fib_nh_release net/ipv4/fib_semantics.c:227 [inline]
 free_fib_info_rcu+0x254/0x4e0 net/ipv4/fib_semantics.c:239
 rcu_do_batch kernel/rcu/tree.c:2430 [inline]
 rcu_core+0x5ca/0x1130 kernel/rcu/tree.c:2658
 __do_softirq+0x1f8/0xb23 kernel/softirq.c:298
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 do_softirq_own_stack+0x9d/0xd0 arch/x86/kernel/irq_64.c:77
 do_softirq kernel/softirq.c:343 [inline]
 do_softirq+0x154/0x1b0 kernel/softirq.c:330
 __local_bh_enable_ip+0x196/0x1f0 kernel/softirq.c:195
 local_bh_enable include/linux/bottom_half.h:32 [inline]
 get_next_corpse net/netfilter/nf_conntrack_core.c:2226 [inline]
 nf_ct_iterate_cleanup+0x9e/0x330 net/netfilter/nf_conntrack_core.c:2249
 nf_ct_iterate_cleanup_net net/netfilter/nf_conntrack_core.c:2334 [inline]
 nf_ct_iterate_cleanup_net+0x113/0x170 net/netfilter/nf_conntrack_core.c:2319
 masq_device_event+0xae/0xe0 net/netfilter/nf_nat_masquerade.c:88
 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2033
 call_netdevice_notifiers_extack net/core/dev.c:2045 [inline]
 call_netdevice_notifiers net/core/dev.c:2059 [inline]
 dev_close_many+0x30b/0x650 net/core/dev.c:1634
 rollback_registered_many+0x3a8/0x1250 net/core/dev.c:9261
 unregister_netdevice_many.part.0+0x1a/0x2f0 net/core/dev.c:10429
 unregister_netdevice_many net/core/dev.c:10428 [inline]
 default_device_exit_batch+0x30c/0x3d0 net/core/dev.c:10912
 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:189
 cleanup_net+0x4ea/0xa00 net/core/net_namespace.c:603
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Modules linked in:
---[ end trace 6802e55574649838 ]---
RIP: 0010:dst_dev_put+0x1d/0x220 net/core/dst.c:156
Code: cc cc cc cc cc cc cc cc cc cc cc cc cc 41 54 55 53 48 89 fb e8 24 79 07 fb 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 8b 01 00 00 48 8d 7b 3a 4c 8b 23 48 b8 00 00 00
RSP: 0018:ffffc90000007d78 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000258 RCX: ffffffff86f86f45
RDX: 000000000000004b RSI: ffffffff866ec51c RDI: 0000000000000258
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8d0c09ff
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000007
R13: fffffbfff16b2cfc R14: 0000607f518d0058 R15: 0000000000000258
FS:  0000000000000000(0000) GS:ffff8880ae400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff0687f7ab4 CR3: 0000000009e8d000 CR4: 00000000001526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600