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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 ffff88803acfcf61 by task syz-executor.0/4628

CPU: 0 PID: 4628 Comm: syz-executor.0 Not tainted 6.5.0-syzkaller-12674-gac28b1ec6135 #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: 0033:0x7fa23067cae9
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:00007fa2314730c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007fa23079bf80 RCX: 00007fa23067cae9
RDX: 0000000000000002 RSI: 00000000200019c0 RDI: 0000000000000004
RBP: 00007fa2306c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fa23079bf80 R15: 00007ffdddeb17f8
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0000eb3f00 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 pfn:0x3acfc
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffff7f(buddy)
raw: 00fff00000000000 ffffea0000e9e308 ffffea0000e3f208 0000000000000000
raw: 0000000000000000 0000000000000002 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 3350, tgid 3337 (syz-executor.0), ts 967032659976, free_ts 980916537604
 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
 alloc_slab_page mm/slub.c:1870 [inline]
 allocate_slab+0x251/0x380 mm/slub.c:2017
 new_slab mm/slub.c:2070 [inline]
 ___slab_alloc+0x8be/0x1570 mm/slub.c:3223
 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3322
 __slab_alloc_node mm/slub.c:3375 [inline]
 slab_alloc_node mm/slub.c:3468 [inline]
 kmem_cache_alloc_node+0x137/0x3f0 mm/slub.c:3523
 kmalloc_reserve+0x166/0x260 net/core/skbuff.c:559
 __alloc_skb+0x12b/0x330 net/core/skbuff.c:650
 alloc_skb include/linux/skbuff.h:1286 [inline]
 alloc_skb_with_frags+0xe4/0x710 net/core/skbuff.c:6313
 sock_alloc_send_pskb+0x7e4/0x970 net/core/sock.c:2795
 sock_alloc_send_skb include/net/sock.h:1885 [inline]
 __ip6_append_data.isra.0+0x2703/0x47f0 net/ipv6/ip6_output.c:1703
 ip6_make_skb+0x304/0x5a0 net/ipv6/ip6_output.c:2096
 udpv6_sendmsg+0x2485/0x2fa0 net/ipv6/udp.c:1570
 inet6_sendmsg+0x9d/0xe0 net/ipv6/af_inet6.c:655
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
 __unfreeze_partials+0x21d/0x240 mm/slub.c:2655
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x18b/0x1d0 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x65/0x90 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:186 [inline]
 slab_post_alloc_hook mm/slab.h:762 [inline]
 slab_alloc_node mm/slub.c:3478 [inline]
 slab_alloc mm/slub.c:3486 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3493 [inline]
 kmem_cache_alloc+0x172/0x3b0 mm/slub.c:3502
 mt_alloc_one lib/maple_tree.c:160 [inline]
 mas_alloc_nodes+0x182/0x830 lib/maple_tree.c:1249
 mas_node_count_gfp+0x105/0x130 lib/maple_tree.c:1329
 mas_preallocate+0x2d7/0xda0 lib/maple_tree.c:5467
 vma_iter_prealloc mm/internal.h:1077 [inline]
 __split_vma+0x435/0x1070 mm/mmap.c:2355
 do_vmi_align_munmap+0x360/0x15f0 mm/mmap.c:2477
 do_vmi_munmap+0x20e/0x450 mm/mmap.c:2623
 mmap_region+0x184/0x28b0 mm/mmap.c:2673
 do_mmap+0x893/0xef0 mm/mmap.c:1354
 vm_mmap_pgoff+0x1a8/0x3b0 mm/util.c:546

Memory state around the buggy address:
 ffff88803acfce00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88803acfce80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88803acfcf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                       ^
 ffff88803acfcf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88803acfd000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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