syzbot

==================================================================
BUG: KASAN: slab-use-after-free in hlist_add_head include/linux/list.h:1034 [inline]
BUG: KASAN: slab-use-after-free in fib6_add+0x42a7/0x4700 net/ipv6/ip6_fib.c:1490
Write of size 8 at addr ffff888000cce440 by task syz-executor.1/1220

CPU: 2 PID: 1220 Comm: syz-executor.1 Not tainted 6.6.0-syzkaller-12401-g8f6f76a6a29f #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xc4/0x620 mm/kasan/report.c:475
 kasan_report+0xda/0x110 mm/kasan/report.c:588
 hlist_add_head include/linux/list.h:1034 [inline]
 fib6_add+0x42a7/0x4700 net/ipv6/ip6_fib.c:1490
 __ip6_ins_rt net/ipv6/route.c:1303 [inline]
 ip6_route_add+0x8d/0x150 net/ipv6/route.c:3847
 rt6_add_dflt_router+0x24b/0x480 net/ipv6/route.c:4375
 ndisc_router_discovery+0xa26/0x3550 net/ipv6/ndisc.c:1384
 ndisc_rcv+0x3de/0x5f0 net/ipv6/ndisc.c:1856
 icmpv6_rcv+0x10cb/0x1750 net/ipv6/icmp.c:979
 ip6_protocol_deliver_rcu+0x33b/0x13d0 net/ipv6/ip6_input.c:438
 ip6_input_finish+0x14f/0x2f0 net/ipv6/ip6_input.c:483
 NF_HOOK include/linux/netfilter.h:314 [inline]
 NF_HOOK include/linux/netfilter.h:308 [inline]
 ip6_input+0xce/0x440 net/ipv6/ip6_input.c:492
 ip6_mc_input+0x48b/0xf40 net/ipv6/ip6_input.c:586
 dst_input include/net/dst.h:461 [inline]
 ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline]
 NF_HOOK include/linux/netfilter.h:314 [inline]
 NF_HOOK include/linux/netfilter.h:308 [inline]
 ipv6_rcv+0x563/0x720 net/ipv6/ip6_input.c:310
 __netif_receive_skb_one_core+0x115/0x180 net/core/dev.c:5527
 __netif_receive_skb+0x1f/0x1b0 net/core/dev.c:5641
 netif_receive_skb_internal net/core/dev.c:5727 [inline]
 netif_receive_skb+0x133/0x700 net/core/dev.c:5786
 tun_rx_batched+0x429/0x780 drivers/net/tun.c:1579
 tun_get_user+0x29e3/0x3bc0 drivers/net/tun.c:2002
 tun_chr_write_iter+0xe8/0x210 drivers/net/tun.c:2048
 call_write_iter include/linux/fs.h:2020 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x64f/0xdf0 fs/read_write.c:584
 ksys_write+0x12f/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7fa322a7b82f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 b9 80 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 0c 81 02 00 48
RSP: 002b:00007fa323764090 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fa322b9bf80 RCX: 00007fa322a7b82f
RDX: 00000000000003b6 RSI: 0000000020000600 RDI: 00000000000000c8
RBP: 00007fa322ac847a R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000003b6 R11: 0000000000000293 R12: 0000000000000000
R13: 000000000000000b R14: 00007fa322b9bf80 R15: 00007ffcc44ee8b8
 </TASK>

Allocated by task 1208:
 kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0xa3/0xb0 mm/kasan/common.c:383
 kasan_kmalloc include/linux/kasan.h:198 [inline]
 __do_kmalloc_node mm/slab_common.c:1007 [inline]
 __kmalloc+0x60/0x100 mm/slab_common.c:1020
 kmalloc include/linux/slab.h:604 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 fib6_info_alloc+0x40/0x160 net/ipv6/ip6_fib.c:155
 ip6_route_info_create+0x337/0x1e70 net/ipv6/route.c:3749
 ip6_route_add+0x26/0x150 net/ipv6/route.c:3843
 rt6_add_dflt_router+0x24b/0x480 net/ipv6/route.c:4375
 ndisc_router_discovery+0xa26/0x3550 net/ipv6/ndisc.c:1384
 ndisc_rcv+0x3de/0x5f0 net/ipv6/ndisc.c:1856
 icmpv6_rcv+0x10cb/0x1750 net/ipv6/icmp.c:979
 ip6_protocol_deliver_rcu+0x33b/0x13d0 net/ipv6/ip6_input.c:438
 ip6_input_finish+0x14f/0x2f0 net/ipv6/ip6_input.c:483
 NF_HOOK include/linux/netfilter.h:314 [inline]
 NF_HOOK include/linux/netfilter.h:308 [inline]
 ip6_input+0xce/0x440 net/ipv6/ip6_input.c:492
 ip6_mc_input+0x48b/0xf40 net/ipv6/ip6_input.c:586
 dst_input include/net/dst.h:461 [inline]
 ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline]
 NF_HOOK include/linux/netfilter.h:314 [inline]
 NF_HOOK include/linux/netfilter.h:308 [inline]
 ipv6_rcv+0x563/0x720 net/ipv6/ip6_input.c:310
 __netif_receive_skb_one_core+0x115/0x180 net/core/dev.c:5527
 __netif_receive_skb+0x1f/0x1b0 net/core/dev.c:5641
 netif_receive_skb_internal net/core/dev.c:5727 [inline]
 netif_receive_skb+0x133/0x700 net/core/dev.c:5786
 tun_rx_batched+0x429/0x780 drivers/net/tun.c:1579
 tun_get_user+0x29e3/0x3bc0 drivers/net/tun.c:2002
 tun_chr_write_iter+0xe8/0x210 drivers/net/tun.c:2048
 call_write_iter include/linux/fs.h:2020 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x64f/0xdf0 fs/read_write.c:584
 ksys_write+0x12f/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Freed by task 0:
 kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:522
 ____kasan_slab_free mm/kasan/common.c:236 [inline]
 ____kasan_slab_free+0x138/0x190 mm/kasan/common.c:200
 kasan_slab_free include/linux/kasan.h:164 [inline]
 __cache_free mm/slab.c:3370 [inline]
 __do_kmem_cache_free mm/slab.c:3557 [inline]
 __kmem_cache_free+0xcc/0x3d0 mm/slab.c:3564
 rcu_do_batch kernel/rcu/tree.c:2153 [inline]
 rcu_core+0x830/0x1c50 kernel/rcu/tree.c:2417
 __do_softirq+0x21a/0x968 kernel/softirq.c:553

Last potentially related work creation:
 kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
 __kasan_record_aux_stack+0x78/0x80 mm/kasan/generic.c:492
 __call_rcu_common.constprop.0+0x9a/0x790 kernel/rcu/tree.c:2667
 fib6_info_release include/net/ip6_fib.h:332 [inline]
 fib6_info_release include/net/ip6_fib.h:329 [inline]
 ndisc_router_discovery+0x2820/0x3550 net/ipv6/ndisc.c:1599
 ndisc_rcv+0x3de/0x5f0 net/ipv6/ndisc.c:1856
 icmpv6_rcv+0x10cb/0x1750 net/ipv6/icmp.c:979
 ip6_protocol_deliver_rcu+0x33b/0x13d0 net/ipv6/ip6_input.c:438
 ip6_input_finish+0x14f/0x2f0 net/ipv6/ip6_input.c:483
 NF_HOOK include/linux/netfilter.h:314 [inline]
 NF_HOOK include/linux/netfilter.h:308 [inline]
 ip6_input+0xce/0x440 net/ipv6/ip6_input.c:492
 ip6_mc_input+0x48b/0xf40 net/ipv6/ip6_input.c:586
 dst_input include/net/dst.h:461 [inline]
 ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline]
 NF_HOOK include/linux/netfilter.h:314 [inline]
 NF_HOOK include/linux/netfilter.h:308 [inline]
 ipv6_rcv+0x563/0x720 net/ipv6/ip6_input.c:310
 __netif_receive_skb_one_core+0x115/0x180 net/core/dev.c:5527
 __netif_receive_skb+0x1f/0x1b0 net/core/dev.c:5641
 netif_receive_skb_internal net/core/dev.c:5727 [inline]
 netif_receive_skb+0x133/0x700 net/core/dev.c:5786
 tun_rx_batched+0x429/0x780 drivers/net/tun.c:1579
 tun_get_user+0x29e3/0x3bc0 drivers/net/tun.c:2002
 tun_chr_write_iter+0xe8/0x210 drivers/net/tun.c:2048
 call_write_iter include/linux/fs.h:2020 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x64f/0xdf0 fs/read_write.c:584
 ksys_write+0x12f/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Second to last potentially related work creation:
 kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
 __kasan_record_aux_stack+0x78/0x80 mm/kasan/generic.c:492
 __call_rcu_common.constprop.0+0x9a/0x790 kernel/rcu/tree.c:2667
 in_dev_finish_destroy+0x15c/0x1d0 net/ipv4/devinet.c:258
 in_dev_put include/linux/inetdevice.h:279 [inline]
 inetdev_destroy net/ipv4/devinet.c:332 [inline]
 inetdev_event+0x1660/0x1980 net/ipv4/devinet.c:1623
 notifier_call_chain+0xb6/0x3b0 kernel/notifier.c:93
 call_netdevice_notifiers_info+0xbe/0x130 net/core/dev.c:1965
 call_netdevice_notifiers_extack net/core/dev.c:2003 [inline]
 call_netdevice_notifiers net/core/dev.c:2017 [inline]
 unregister_netdevice_many_notify+0x858/0x1980 net/core/dev.c:10983
 ip6gre_exit_batch_net+0x40d/0x5b0 net/ipv6/ip6_gre.c:1643
 ops_exit_list+0x125/0x170 net/core/net_namespace.c:175
 cleanup_net+0x505/0xb20 net/core/net_namespace.c:614
 process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
 kthread+0x33c/0x440 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

The buggy address belongs to the object at ffff888000cce400
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 64 bytes inside of
 freed 512-byte region [ffff888000cce400, ffff888000cce600)

The buggy address belongs to the physical page:
page:ffffea0000033380 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xcce
flags: 0x7ff00000000800(slab|node=0|zone=0|lastcpupid=0x7ff)
page_type: 0x4()
raw: 007ff00000000800 ffff888013040600 ffffea000156ee90 ffffea00018e1b90
raw: 0000000000000000 ffff888000cce000 0000000100000004 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 5202, tgid 5202 (syz-executor.1), ts 142600045742, free_ts 0
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1537
 prep_new_page mm/page_alloc.c:1544 [inline]
 get_page_from_freelist+0xa25/0x36c0 mm/page_alloc.c:3312
 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4568
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 kmem_getpages mm/slab.c:1356 [inline]
 cache_grow_begin+0x99/0x3a0 mm/slab.c:2550
 cache_alloc_refill+0x294/0x3a0 mm/slab.c:2923
 ____cache_alloc mm/slab.c:2999 [inline]
 ____cache_alloc mm/slab.c:2982 [inline]
 __do_cache_alloc mm/slab.c:3182 [inline]
 slab_alloc_node mm/slab.c:3230 [inline]
 __kmem_cache_alloc_node+0x3ba/0x460 mm/slab.c:3521
 kmalloc_trace+0x25/0xe0 mm/slab_common.c:1098
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 inetdev_init+0x66/0x570 net/ipv4/devinet.c:269
 inetdev_event+0x1185/0x1980 net/ipv4/devinet.c:1555
 notifier_call_chain+0xb6/0x3b0 kernel/notifier.c:93
 call_netdevice_notifiers_info+0xbe/0x130 net/core/dev.c:1965
 call_netdevice_notifiers_extack net/core/dev.c:2003 [inline]
 call_netdevice_notifiers net/core/dev.c:2017 [inline]
 register_netdevice+0xf98/0x14a0 net/core/dev.c:10197
 nsim_init_netdevsim drivers/net/netdevsim/netdev.c:343 [inline]
 nsim_create+0x46f/0x600 drivers/net/netdevsim/netdev.c:395
 __nsim_dev_port_add+0x494/0x8a0 drivers/net/netdevsim/dev.c:1390
 nsim_dev_port_add_all drivers/net/netdevsim/dev.c:1446 [inline]
 nsim_drv_probe+0xdbb/0x1490 drivers/net/netdevsim/dev.c:1604
 call_driver_probe drivers/base/dd.c:579 [inline]
 really_probe+0x234/0xc90 drivers/base/dd.c:658
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888000cce300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888000cce380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888000cce400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888000cce480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888000cce500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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