==================================================================
BUG: KASAN: use-after-free in __xfrm_state_lookup+0x6ad/0x8d0
Read of size 2 at addr ffff888110b7c142 by task syz.2.1546/11076

CPU: 1 UID: 0 PID: 11076 Comm: syz.2.1546 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_user_state_lookup+0x231/0x370
 xfrm_get_sa+0x93/0x290
 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: 0033:0x7f4cb498ebe9
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:00007f4cb57ea038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f4cb4bc5fa0 RCX: 00007f4cb498ebe9
RDX: 0000000024004040 RSI: 00002000000014c0 RDI: 0000000000000008
RBP: 00007f4cb4a11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4cb4bc6038 R14: 00007f4cb4bc5fa0 R15: 00007ffc4f7696c8
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888110b7d680 pfn:0x110b7c
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000000000 ffffea0004394808 ffffea0004814208 0000000000000000
raw: ffff888110b7d680 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x446dc0(GFP_KERNEL_ACCOUNT|__GFP_ZERO|__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_COMP), pid 10569, tgid 10568 (syz.0.1401), ts 153122097470, free_ts 153204804100
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x21e4/0x22c0
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 ___kmalloc_large_node+0x5f/0x1b0
 __kmalloc_large_node_noprof+0x18/0x90
 __kvmalloc_node_noprof+0x6d/0x5f0
 alloc_netdev_mqs+0xa3/0x11b0
 tun_set_iff+0x532/0xef0
 __tun_chr_ioctl+0x788/0x1df0
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 10577 tgid 10568 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 free_large_kmalloc+0x13a/0x1f0
 device_release+0x9c/0x1c0
 kobject_put+0x22b/0x480
 netdev_run_todo+0xd2e/0xea0
 tun_chr_close+0x13c/0x1c0
 __fput+0x44c/0xa70
 task_work_run+0x1d4/0x260
 do_exit+0x6b5/0x2300
 do_group_exit+0x21c/0x2d0
 get_signal+0x1286/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 exit_to_user_mode_loop+0x75/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888110b7c000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888110b7c080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888110b7c100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff888110b7c180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888110b7c200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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