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BUG: KASAN: use-after-free in xfrm_alloc_spi+0x570/0xf30
Read of size 4 at addr ffff8880260080c4 by task syz.8.6284/32487

CPU: 1 UID: 0 PID: 32487 Comm: syz.8.6284 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_alloc_spi+0x570/0xf30
 xfrm_alloc_userspi+0x70b/0xc90
 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: 0033:0x7f6ae9f8ec29
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:00007f6aeae95038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f6aea1d5fa0 RCX: 00007f6ae9f8ec29
RDX: 0000000000000000 RSI: 0000200000001580 RDI: 0000000000000003
RBP: 00007f6aea011e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6aea1d6038 R14: 00007f6aea1d5fa0 R15: 00007fffbc646a28
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x16f0 pfn:0x26008
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0000901bc8 ffffea0000980248 0000000000000000
raw: 00000000000016f0 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 0x140cc2(GFP_HIGHUSER|__GFP_COMP), pid 31909, tgid 31909 (syz.7.6134), ts 1153199600387, free_ts 1166641841186
 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
 folio_alloc_noprof+0x1e/0x30
 filemap_alloc_folio_noprof+0xdf/0x470
 __filemap_get_folio+0x3f2/0xaf0
 simple_write_begin+0x61/0x500
 generic_perform_write+0x2c5/0x900
 generic_file_write_iter+0x117/0x550
 __kernel_write_iter+0x428/0x910
 dump_user_range+0x8a0/0xc90
 elf_core_dump+0x337b/0x3990
 coredump_write+0x1169/0x1900
 vfs_coredump+0x1daa/0x2a50
page last free pid 32289 tgid 32289 stack trace:
 free_unref_folios+0xdbd/0x1520
 folios_put_refs+0x559/0x640
 truncate_inode_pages_range+0x346/0xda0
 evict+0x517/0x9c0
 do_unlinkat+0x39f/0x560
 coredump_file+0x1a5/0xaf0
 vfs_coredump+0x1688/0x2a50
 get_signal+0x1109/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 irqentry_exit_to_user_mode+0x81/0x120
 exc_page_fault+0x9f/0xf0
 asm_exc_page_fault+0x26/0x30

Memory state around the buggy address:
 ffff888026007f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888026008000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888026008080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff888026008100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888026008180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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