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BUG: KASAN: use-after-free in __xfrm_state_lookup+0x6ad/0x8d0
Read of size 2 at addr ffff8880297f17c2 by task syz.1.5591/18758

CPU: 1 UID: 0 PID: 18758 Comm: syz.1.5591 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_add+0x27d/0xc40
 pfkey_add+0x1edd/0x2e00
 pfkey_sendmsg+0xbfe/0x1090
 __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: 0033:0x7f54c238eba9
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:00007f54c32f5038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f54c25d5fa0 RCX: 00007f54c238eba9
RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000003
RBP: 00007f54c2411e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f54c25d6038 R14: 00007f54c25d5fa0 R15: 00007ffedc71f758
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffffffffffffffff pfn:0x297f1
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: ffffffffffffffff 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 0x2cc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_NOWARN), pid 17807, tgid 17804 (syz.1.5172), ts 266101748021, free_ts 266136038066
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x21e4/0x22c0
 __alloc_frozen_pages_noprof+0x181/0x370
 __alloc_pages_noprof+0xa/0x30
 pcpu_populate_chunk+0x182/0xb30
 pcpu_alloc_noprof+0xcbf/0x1720
 bpf_map_alloc_percpu+0xbc/0x1b0
 prealloc_init+0x225/0x630
 htab_map_alloc+0x6ce/0xc70
 map_create+0xaa3/0x14d0
 __sys_bpf+0x60f/0x870
 __x64_sys_bpf+0x7c/0x90
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 3145 tgid 3145 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 pcpu_depopulate_chunk+0x45f/0x500
 pcpu_balance_workfn+0x350/0xe00
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30

Memory state around the buggy address:
 ffff8880297f1680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880297f1700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880297f1780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff8880297f1800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880297f1880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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