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BUG: KASAN: use-after-free in decode_session6 net/xfrm/xfrm_policy.c:3389 [inline]
BUG: KASAN: use-after-free in __xfrm_decode_session+0x1d4b/0x2ec0 net/xfrm/xfrm_policy.c:3481
Read of size 1 at addr ffff88805b348857 by task syz-executor.1/29666

CPU: 1 PID: 29666 Comm: syz-executor.1 Not tainted 5.7.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x188/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x413 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 decode_session6 net/xfrm/xfrm_policy.c:3389 [inline]
 __xfrm_decode_session+0x1d4b/0x2ec0 net/xfrm/xfrm_policy.c:3481
 xfrm_decode_session include/net/xfrm.h:1133 [inline]
 vti_tunnel_xmit+0x26b/0x18d0 net/ipv4/ip_vti.c:321
 __netdev_start_xmit include/linux/netdevice.h:4607 [inline]
 netdev_start_xmit include/linux/netdevice.h:4621 [inline]
 xmit_one net/core/dev.c:3545 [inline]
 dev_hard_start_xmit+0x1a4/0x9b0 net/core/dev.c:3561
 sch_direct_xmit+0x345/0xc20 net/sched/sch_generic.c:313
 qdisc_restart net/sched/sch_generic.c:376 [inline]
 __qdisc_run+0x4d1/0x17b0 net/sched/sch_generic.c:384
 __dev_xmit_skb net/core/dev.c:3784 [inline]
 __dev_queue_xmit+0x165b/0x30a0 net/core/dev.c:4089
 neigh_output include/net/neighbour.h:510 [inline]
 ip6_finish_output2+0xf32/0x22d0 net/ipv6/ip6_output.c:117
 ip6_fragment+0x1479/0x2540 net/ipv6/ip6_output.c:920
 __ip6_finish_output+0x573/0xab0 net/ipv6/ip6_output.c:141
 ip6_finish_output+0x34/0x1f0 net/ipv6/ip6_output.c:153
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip6_output+0x239/0x810 net/ipv6/ip6_output.c:176
 dst_output include/net/dst.h:435 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ip6_xmit+0xe1a/0x2090 net/ipv6/ip6_output.c:280
 sctp_v6_xmit+0x33b/0x690 net/sctp/ipv6.c:217
 sctp_packet_transmit+0x19fc/0x3490 net/sctp/output.c:629
 sctp_packet_singleton net/sctp/outqueue.c:773 [inline]
 sctp_outq_flush_ctrl.constprop.0+0x6ca/0xc40 net/sctp/outqueue.c:904
 sctp_outq_flush+0xf8/0x2340 net/sctp/outqueue.c:1186
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1801 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1185 [inline]
 sctp_do_sm+0x4db/0x4ec0 net/sctp/sm_sideeffect.c:1156
 sctp_primitive_ASSOCIATE+0x98/0xc0 net/sctp/primitive.c:73
 sctp_sendmsg_to_asoc+0xc53/0x2100 net/sctp/socket.c:1848
 sctp_sendmsg+0xfce/0x1e50 net/sctp/socket.c:2038
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:814
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 __sys_sendto+0x219/0x330 net/socket.c:1995
 __do_sys_sendto net/socket.c:2007 [inline]
 __se_sys_sendto net/socket.c:2003 [inline]
 __ia32_sys_sendto+0xdb/0x1b0 net/socket.c:2003
 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline]
 do_fast_syscall_32+0x270/0xe90 arch/x86/entry/common.c:396
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

The buggy address belongs to the page:
page:ffffea00016cd200 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000000()
raw: 00fffe0000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88805b348700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805b348780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88805b348800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                 ^
 ffff88805b348880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805b348900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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