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BUG: KASAN: use-after-free in decode_session6+0x10e1/0x1950 net/xfrm/xfrm_policy.c:3460
Read of size 1 at addr ffff88807e5966a4 by task syz-executor.4/17176

CPU: 1 PID: 17176 Comm: syz-executor.4 Not tainted 6.5.0-syzkaller-12673-g73be7fb14e83 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xc4/0x620 mm/kasan/report.c:475
 kasan_report+0xda/0x110 mm/kasan/report.c:588
 decode_session6+0x10e1/0x1950 net/xfrm/xfrm_policy.c:3460
 __xfrm_decode_session+0x54/0xb0 net/xfrm/xfrm_policy.c:3566
 xfrm_decode_session_reverse include/net/xfrm.h:1223 [inline]
 icmpv6_route_lookup+0x397/0x550 net/ipv6/icmp.c:388
 icmp6_send+0x11c1/0x2720 net/ipv6/icmp.c:595
 __icmpv6_send include/linux/icmpv6.h:28 [inline]
 icmpv6_send include/linux/icmpv6.h:49 [inline]
 ip6_link_failure+0x31/0x5a0 net/ipv6/route.c:2787
 dst_link_failure include/net/dst.h:437 [inline]
 ip6_tnl_xmit+0x4f9/0x3900 net/ipv6/ip6_tunnel.c:1268
 ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1384 [inline]
 ip6_tnl_start_xmit+0x6ef/0x1750 net/ipv6/ip6_tunnel.c:1432
 __netdev_start_xmit include/linux/netdevice.h:4889 [inline]
 netdev_start_xmit include/linux/netdevice.h:4903 [inline]
 xmit_one net/core/dev.c:3544 [inline]
 dev_hard_start_xmit+0x13d/0x6c0 net/core/dev.c:3560
 sch_direct_xmit+0x1ac/0xc20 net/sched/sch_generic.c:342
 qdisc_restart net/sched/sch_generic.c:407 [inline]
 __qdisc_run+0x540/0x19d0 net/sched/sch_generic.c:415
 __dev_xmit_skb net/core/dev.c:3834 [inline]
 __dev_queue_xmit+0x24f9/0x3d80 net/core/dev.c:4306
 dev_queue_xmit include/linux/netdevice.h:3082 [inline]
 neigh_connected_output+0x42c/0x5d0 net/core/neighbour.c:1581
 neigh_output include/net/neighbour.h:542 [inline]
 ip6_finish_output2+0x610/0x1b20 net/ipv6/ip6_output.c:135
 __ip6_finish_output net/ipv6/ip6_output.c:196 [inline]
 ip6_finish_output+0x485/0x1250 net/ipv6/ip6_output.c:207
 NF_HOOK_COND include/linux/netfilter.h:293 [inline]
 ip6_output+0x23a/0x880 net/ipv6/ip6_output.c:228
 dst_output include/net/dst.h:458 [inline]
 ip6_local_out+0xaf/0x190 net/ipv6/output_core.c:155
 ip6_send_skb+0xb7/0x330 net/ipv6/ip6_output.c:2017
 udp_v6_send_skb+0x9b2/0x1900 net/ipv6/udp.c:1282
 udpv6_sendmsg+0x24d1/0x2fa0 net/ipv6/udp.c:1576
 inet6_sendmsg+0x9d/0xe0 net/ipv6/af_inet6.c:655
 sock_sendmsg_nosec net/socket.c:730 [inline]
 sock_sendmsg+0xd9/0x180 net/socket.c:753
 ____sys_sendmsg+0x2ac/0x940 net/socket.c:2541
 ___sys_sendmsg+0x135/0x1d0 net/socket.c:2595
 __sys_sendmmsg+0x1a1/0x450 net/socket.c:2681
 __do_sys_sendmmsg net/socket.c:2710 [inline]
 __se_sys_sendmmsg net/socket.c:2707 [inline]
 __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2707
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fca0fa7cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fca107080c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007fca0fb9bf80 RCX: 00007fca0fa7cae9
RDX: 0000000000000003 RSI: 0000000020000f40 RDI: 0000000000000003
RBP: 00007fca0fac847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fca0fb9bf80 R15: 00007fff1f7b0d48
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001f96580 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 pfn:0x7e596
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffff7f(buddy)
raw: 00fff00000000000 ffffea0001083f08 ffffea000143d588 0000000000000000
raw: 0000000000000000 0000000000000001 00000000ffffff7f 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 0x100cc0(GFP_USER), pid 5093, tgid 5093 (syz-executor.1), ts 1608346039966, free_ts 1661948026809
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1536
 prep_new_page mm/page_alloc.c:1543 [inline]
 get_page_from_freelist+0xee0/0x2f20 mm/page_alloc.c:3170
 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4426
 alloc_pages+0x1a9/0x270 mm/mempolicy.c:2298
 __get_free_pages+0xc/0x40 mm/page_alloc.c:4477
 kasan_populate_vmalloc_pte+0x29/0x160 mm/kasan/shadow.c:323
 apply_to_pte_range mm/memory.c:2586 [inline]
 apply_to_pmd_range mm/memory.c:2630 [inline]
 apply_to_pud_range mm/memory.c:2666 [inline]
 apply_to_p4d_range mm/memory.c:2702 [inline]
 __apply_to_page_range+0x5ed/0xdb0 mm/memory.c:2736
 alloc_vmap_area+0x85f/0x2060 mm/vmalloc.c:1641
 __get_vm_area_node+0x132/0x3d0 mm/vmalloc.c:2595
 __vmalloc_node_range+0x27a/0x1540 mm/vmalloc.c:3280
 __vmalloc_node mm/vmalloc.c:3385 [inline]
 vzalloc+0x6b/0x80 mm/vmalloc.c:3458
 alloc_counters net/ipv6/netfilter/ip6_tables.c:815 [inline]
 copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:837 [inline]
 get_entries net/ipv6/netfilter/ip6_tables.c:1039 [inline]
 do_ip6t_get_ctl+0x68d/0xab0 net/ipv6/netfilter/ip6_tables.c:1669
 nf_getsockopt+0x76/0xe0 net/netfilter/nf_sockopt.c:116
 ipv6_getsockopt+0x1f9/0x2b0 net/ipv6/ipv6_sockglue.c:1500
 tcp_getsockopt+0x97/0xf0 net/ipv4/tcp.c:4284
 __sys_getsockopt+0x220/0x6a0 net/socket.c:2354
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1136 [inline]
 free_unref_page_prepare+0x476/0xa40 mm/page_alloc.c:2312
 free_unref_page+0x33/0x3b0 mm/page_alloc.c:2405
 kasan_depopulate_vmalloc_pte+0x63/0x80 mm/kasan/shadow.c:427
 apply_to_pte_range mm/memory.c:2586 [inline]
 apply_to_pmd_range mm/memory.c:2630 [inline]
 apply_to_pud_range mm/memory.c:2666 [inline]
 apply_to_p4d_range mm/memory.c:2702 [inline]
 __apply_to_page_range+0x5ed/0xdb0 mm/memory.c:2736
 kasan_release_vmalloc+0xa8/0xc0 mm/kasan/shadow.c:544
 __purge_vmap_area_lazy+0x8b9/0x2160 mm/vmalloc.c:1770
 drain_vmap_area_work+0x54/0xd0 mm/vmalloc.c:1804
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

Memory state around the buggy address:
 ffff88807e596580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807e596600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88807e596680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff88807e596700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807e596780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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