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BUG: KASAN: use-after-free in __xfrm_state_insert+0x8af/0x1450
Read of size 1 at addr ffff88811e6907b0 by task syz.0.1936/12368

CPU: 0 UID: 0 PID: 12368 Comm: syz.0.1936 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_insert+0x8af/0x1450
 xfrm_state_insert+0x54/0x60
 ipcomp6_init_state+0x655/0x900
 __xfrm_init_state+0xa76/0x13f0
 xfrm_init_state+0x18/0xa0
 pfkey_add+0x1d38/0x2e00
 pfkey_sendmsg+0xbfe/0x1090
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x52d/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __sys_sendmmsg+0x227/0x430
 __x64_sys_sendmmsg+0xa0/0xc0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f495598ec29
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:00007f4956864038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f4955bd5fa0 RCX: 00007f495598ec29
RDX: 000000000400008a RSI: 0000200000000180 RDI: 0000000000000004
RBP: 00007f4955a11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4955bd6038 R14: 00007f4955bd5fa0 R15: 00007fff87374ce8
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88811e690480 pfn:0x11e690
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
page_type: f0(buddy)
raw: 057ff00000000000 ffffea0004793e08 ffffea0004a21508 0000000000000000
raw: ffff88811e690480 0000000000000002 00000000f0000000 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 0x2dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_ZERO|__GFP_NOWARN), pid 11974, tgid 11973 (syz.0.1800), ts 194080252379, free_ts 194143026803
 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
 __vmalloc_node_range_noprof+0x97d/0x12f0
 vmalloc_user_noprof+0xad/0xf0
 xskq_create+0xbf/0x170
 xsk_init_queue+0xb0/0x110
 xsk_setsockopt+0x57b/0x8d0
 do_sock_setsockopt+0x17c/0x1b0
 __x64_sys_setsockopt+0x13f/0x1b0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 11973 tgid 11973 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 vfree+0x25a/0x400
 xskq_destroy+0x40/0x60
 xsk_release+0x4ec/0x700
 sock_close+0xc3/0x240
 __fput+0x44c/0xa70
 task_work_run+0x1d4/0x260
 exit_to_user_mode_loop+0xec/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88811e690680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88811e690700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88811e690780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                     ^
 ffff88811e690800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88811e690880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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