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BUG: KASAN: use-after-free in __xfrm_state_lookup+0x6ad/0x8d0
Read of size 2 at addr ffff88804815e542 by task syz.2.2426/14972

CPU: 1 UID: 0 PID: 14972 Comm: syz.2.2426 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_input_state_lookup+0x6e9/0xa60
 xfrm_input+0x425c/0x72c0
 vti_input+0x219/0x330
 xfrm4_rcv_encap+0x39f/0x620
 udp_queue_rcv_one_skb+0x17b9/0x19e0
 __udp4_lib_mcast_deliver+0xc06/0xcf0
 __udp4_lib_rcv+0x10e2/0x2600
 ip_protocol_deliver_rcu+0x282/0x440
 ip_local_deliver_finish+0x3bb/0x6f0
 NF_HOOK+0x30c/0x3a0
 ip_sublist_rcv_finish+0x221/0x2a0
 ip_sublist_rcv+0x5b1/0xa10
 ip_list_rcv+0x3e2/0x430
 __netif_receive_skb_list_core+0x7d2/0x800
 netif_receive_skb_list_internal+0x96f/0xcb0
 netif_receive_skb_list+0x54/0x450
 bpf_test_run_xdp_live+0x1786/0x1b10
 bpf_prog_test_run_xdp+0x713/0x1000
 bpf_prog_test_run+0x2c7/0x340
 __sys_bpf+0x581/0x870
 __x64_sys_bpf+0x7c/0x90
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f202998ec29
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:00007f202a7bd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f2029bd6090 RCX: 00007f202998ec29
RDX: 0000000000000048 RSI: 0000200000000600 RDI: 000000000000000a
RBP: 00007f2029a11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2029bd6128 R14: 00007f2029bd6090 R15: 00007ffe969ab0a8
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88804815fe00 pfn:0x4815e
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: ffff88804815fe00 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x440dc0(GFP_KERNEL_ACCOUNT|__GFP_ZERO|__GFP_COMP), pid 14660, tgid 14660 (syz.0.2337), ts 247264458676, free_ts 247302851494
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x21e4/0x22c0
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 alloc_pages_noprof+0xa9/0x190
 pte_alloc_one+0x21/0x170
 __pte_alloc+0x25/0x1a0
 __handle_mm_fault+0x49b3/0x5440
 handle_mm_fault+0x40a/0x8e0
 do_user_addr_fault+0xa81/0x1390
 exc_page_fault+0x76/0xf0
 asm_exc_page_fault+0x26/0x30
page last free pid 23 tgid 23 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 __tlb_remove_table+0x2d2/0x3b0
 tlb_remove_table_rcu+0x85/0x100
 rcu_core+0xcab/0x1770
 handle_softirqs+0x286/0x870
 run_ksoftirqd+0x9b/0x100
 smpboot_thread_fn+0x542/0xa60
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30

Memory state around the buggy address:
 ffff88804815e400: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88804815e480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88804815e500: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff88804815e580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88804815e600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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