netlink: 108 bytes leftover after parsing attributes in process `syz.0.1621'.
==================================================================
BUG: KASAN: slab-use-after-free in __xfrm_state_lookup+0x6ad/0x8d0
Read of size 2 at addr ffff888117dac142 by task syz.0.1621/12812

CPU: 0 UID: 0 PID: 12812 Comm: syz.0.1621 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
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 print_report+0xca/0x240
 kasan_report+0x118/0x150
 __xfrm_state_lookup+0x6ad/0x8d0
 xfrm_state_lookup+0x11e/0x1e0
 xfrm_add_sa_expire+0x19c/0x4b0
 xfrm_user_rcv_msg+0x7a3/0xab0
 netlink_rcv_skb+0x208/0x470
 xfrm_netlink_rcv+0x79/0x90
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f714bb8ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f714ca08038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f714bdc5fa0 RCX: 00007f714bb8ebe9
RDX: 0000000000002000 RSI: 0000200000000000 RDI: 0000000000000007
RBP: 00007f714bc11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f714bdc6038 R14: 00007f714bdc5fa0 R15: 00007ffdcb4af868
 </TASK>

Allocated by task 12758:
 kasan_save_track+0x3e/0x80
 __kasan_slab_alloc+0x6c/0x80
 kmem_cache_alloc_node_noprof+0x1bb/0x3c0
 kmalloc_reserve+0xbd/0x290
 __alloc_skb+0x142/0x2d0
 napi_alloc_skb+0x84/0x7d0
 napi_get_frags+0x69/0x140
 netif_napi_add_weight_locked+0x57a/0x970
 gro_cells_init+0x1af/0x220
 ip6_tnl_dev_init+0x85/0x870
 register_netdevice+0x6bf/0x1ae0
 register_netdev+0x40/0x60
 ip6_tnl_init_net+0x259/0x3b0
 ops_init+0x35c/0x5c0
 setup_net+0x10c/0x320
 copy_net_ns+0x31b/0x4d0
 create_new_namespaces+0x3f3/0x720
 unshare_nsproxy_namespaces+0x11c/0x170
 ksys_unshare+0x4c8/0x8c0
 __x64_sys_unshare+0x38/0x50
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 12758:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5b/0x80
 kmem_cache_free+0x18f/0x400
 skb_release_data+0x62d/0x7c0
 sk_skb_reason_drop+0x127/0x170
 netif_napi_add_weight_locked+0x5f1/0x970
 gro_cells_init+0x1af/0x220
 ip6_tnl_dev_init+0x85/0x870
 register_netdevice+0x6bf/0x1ae0
 register_netdev+0x40/0x60
 ip6_tnl_init_net+0x259/0x3b0
 ops_init+0x35c/0x5c0
 setup_net+0x10c/0x320
 copy_net_ns+0x31b/0x4d0
 create_new_namespaces+0x3f3/0x720
 unshare_nsproxy_namespaces+0x11c/0x170
 ksys_unshare+0x4c8/0x8c0
 __x64_sys_unshare+0x38/0x50
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888117dac000
 which belongs to the cache skbuff_small_head of size 704
The buggy address is located 322 bytes inside of
 freed 704-byte region [ffff888117dac000, ffff888117dac2c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x117dac
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x57ff00000000040(head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000040 ffff88801caf6c80 ffffea0004688d00 dead000000000002
raw: 0000000000000000 0000000000120012 00000000f5000000 0000000000000000
head: 057ff00000000040 ffff88801caf6c80 ffffea0004688d00 dead000000000002
head: 0000000000000000 0000000000120012 00000000f5000000 0000000000000000
head: 057ff00000000002 ffffea00045f6b01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5790, tgid 5790 (sshd), ts 180296708185, free_ts 176066095718
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x21e4/0x22c0
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 allocate_slab+0x8a/0x370
 ___slab_alloc+0xbeb/0x1420
 kmem_cache_alloc_node_noprof+0x280/0x3c0
 kmalloc_reserve+0xbd/0x290
 __alloc_skb+0x142/0x2d0
 tcp_stream_alloc_skb+0x3d/0x340
 tcp_sendmsg_locked+0xf38/0x5620
 tcp_sendmsg+0x2f/0x50
 __sock_sendmsg+0x19c/0x270
 sock_write_iter+0x258/0x330
 vfs_write+0x5c9/0xb30
 ksys_write+0x145/0x250
page last free pid 10477 tgid 10477 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 __slab_free+0x303/0x3c0
 qlist_free_all+0x97/0x140
 kasan_quarantine_reduce+0x148/0x160
 __kasan_slab_alloc+0x22/0x80
 kmem_cache_alloc_noprof+0x1c1/0x3c0
 vm_area_dup+0x2b/0x680
 __split_vma+0x1a9/0xa00
 vms_gather_munmap_vmas+0x2ea/0x12f0
 mmap_region+0x724/0x20c0
 do_mmap+0xc45/0x10d0
 vm_mmap_pgoff+0x2a6/0x4d0
 ksys_mmap_pgoff+0x51f/0x760
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888117dac000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888117dac080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888117dac100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888117dac180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888117dac200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
