==================================================================
BUG: KASAN: slab-use-after-free in ipv6_addr_equal include/net/ipv6.h:673 [inline]
BUG: KASAN: slab-use-after-free in ip6gre_xmit_ipv6 net/ipv6/ip6_gre.c:862 [inline]
BUG: KASAN: slab-use-after-free in ip6gre_tunnel_xmit+0x6cd/0x1710 net/ipv6/ip6_gre.c:925
Read of size 8 at addr ffff88805cc855dc by task syz.0.3200/16612

CPU: 0 UID: 0 PID: 16612 Comm: syz.0.3200 Not tainted 6.13.0-rc3-syzkaller-00062-gc061cf420ded #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:489
 kasan_report+0x143/0x180 mm/kasan/report.c:602
 ipv6_addr_equal include/net/ipv6.h:673 [inline]
 ip6gre_xmit_ipv6 net/ipv6/ip6_gre.c:862 [inline]
 ip6gre_tunnel_xmit+0x6cd/0x1710 net/ipv6/ip6_gre.c:925
 __netdev_start_xmit include/linux/netdevice.h:5002 [inline]
 netdev_start_xmit include/linux/netdevice.h:5011 [inline]
 xmit_one net/core/dev.c:3590 [inline]
 dev_hard_start_xmit+0x27a/0x7d0 net/core/dev.c:3606
 sch_direct_xmit+0x29c/0x5d0 net/sched/sch_generic.c:343
 __dev_xmit_skb net/core/dev.c:3827 [inline]
 __dev_queue_xmit+0x1a8f/0x3f50 net/core/dev.c:4400
 packet_snd net/packet/af_packet.c:3146 [inline]
 packet_sendmsg+0x4e61/0x6a40 net/packet/af_packet.c:3178
 sock_sendmsg_nosec net/socket.c:711 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:726
 __sys_sendto+0x363/0x4c0 net/socket.c:2197
 __do_sys_sendto net/socket.c:2204 [inline]
 __se_sys_sendto net/socket.c:2200 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2200
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7facd8585d29
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:00007facd9324038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007facd8776080 RCX: 00007facd8585d29
RDX: 0000000000000028 RSI: 0000000020000180 RDI: 0000000000000005
RBP: 00007facd8601a20 R08: 0000000020000140 R09: 0000000000000014
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007facd8776080 R15: 00007ffc0d700b98
 </TASK>

Allocated by task 16612:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4119 [inline]
 slab_alloc_node mm/slub.c:4168 [inline]
 kmem_cache_alloc_node_noprof+0x1d9/0x380 mm/slub.c:4220
 kmalloc_reserve+0xa8/0x2a0 net/core/skbuff.c:587
 __alloc_skb+0x1f3/0x440 net/core/skbuff.c:678
 alloc_skb include/linux/skbuff.h:1323 [inline]
 alloc_skb_with_frags+0xc3/0x820 net/core/skbuff.c:6612
 sock_alloc_send_pskb+0x91a/0xa60 net/core/sock.c:2881
 packet_alloc_skb net/packet/af_packet.c:2995 [inline]
 packet_snd net/packet/af_packet.c:3089 [inline]
 packet_sendmsg+0x3fe8/0x6a40 net/packet/af_packet.c:3178
 sock_sendmsg_nosec net/socket.c:711 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:726
 __sys_sendto+0x363/0x4c0 net/socket.c:2197
 __do_sys_sendto net/socket.c:2204 [inline]
 __se_sys_sendto net/socket.c:2200 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2200
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 16612:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:582
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2353 [inline]
 slab_free mm/slub.c:4613 [inline]
 kmem_cache_free+0x195/0x410 mm/slub.c:4715
 skb_kfree_head net/core/skbuff.c:1084 [inline]
 skb_free_head net/core/skbuff.c:1098 [inline]
 skb_release_data+0x677/0x8a0 net/core/skbuff.c:1125
 skb_release_all net/core/skbuff.c:1190 [inline]
 __kfree_skb net/core/skbuff.c:1204 [inline]
 sk_skb_reason_drop+0x1c9/0x380 net/core/skbuff.c:1242
 packet_rcv+0x16f/0x14b0 net/packet/af_packet.c:2291
 dev_queue_xmit_nit+0xb6e/0xca0 net/core/dev.c:2347
 xmit_one net/core/dev.c:3586 [inline]
 dev_hard_start_xmit+0x15f/0x7d0 net/core/dev.c:3606
 sch_direct_xmit+0x29c/0x5d0 net/sched/sch_generic.c:343
 __dev_xmit_skb net/core/dev.c:3827 [inline]
 __dev_queue_xmit+0x1a8f/0x3f50 net/core/dev.c:4400
 packet_snd net/packet/af_packet.c:3146 [inline]
 packet_sendmsg+0x4e61/0x6a40 net/packet/af_packet.c:3178
 sock_sendmsg_nosec net/socket.c:711 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:726
 __sys_sendto+0x363/0x4c0 net/socket.c:2197
 __do_sys_sendto net/socket.c:2204 [inline]
 __se_sys_sendto net/socket.c:2200 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2200
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88805cc85500
 which belongs to the cache skbuff_small_head of size 640
The buggy address is located 220 bytes inside of
 freed 640-byte region [ffff88805cc85500, ffff88805cc85780)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5cc84
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
ksm flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff8881416d6a00 ffffea0001886800 dead000000000003
raw: 0000000000000000 0000000080150015 00000001f5000000 0000000000000000
head: 00fff00000000040 ffff8881416d6a00 ffffea0001886800 dead000000000003
head: 0000000000000000 0000000080150015 00000001f5000000 0000000000000000
head: 00fff00000000002 ffffea0001732101 ffffffffffffffff 0000000000000000
head: 0000000000000004 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 12993, tgid 12993 (syz-executor), ts 713663269473, free_ts 712091903137
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1556
 prep_new_page mm/page_alloc.c:1564 [inline]
 get_page_from_freelist+0x3651/0x37a0 mm/page_alloc.c:3474
 __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4751
 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2269
 alloc_slab_page+0x6a/0x110 mm/slub.c:2423
 allocate_slab+0x5a/0x2b0 mm/slub.c:2589
 new_slab mm/slub.c:2642 [inline]
 ___slab_alloc+0xc27/0x14a0 mm/slub.c:3830
 __slab_alloc+0x58/0xa0 mm/slub.c:3920
 __slab_alloc_node mm/slub.c:3995 [inline]
 slab_alloc_node mm/slub.c:4156 [inline]
 kmem_cache_alloc_node_noprof+0x269/0x380 mm/slub.c:4220
 kmalloc_reserve+0xa8/0x2a0 net/core/skbuff.c:587
 __alloc_skb+0x1f3/0x440 net/core/skbuff.c:678
 alloc_skb include/linux/skbuff.h:1323 [inline]
 nlmsg_new include/net/netlink.h:1018 [inline]
 netlink_ack+0x145/0xa50 net/netlink/af_netlink.c:2479
 netlink_rcv_skb+0x262/0x430 net/netlink/af_netlink.c:2548
 netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
 netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1347
 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1891
 sock_sendmsg_nosec net/socket.c:711 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:726
page last free pid 13036 tgid 13034 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_unref_page+0xd2c/0x1000 mm/page_alloc.c:2657
 discard_slab mm/slub.c:2688 [inline]
 __put_partials+0x160/0x1c0 mm/slub.c:3157
 put_cpu_partial+0x17c/0x250 mm/slub.c:3232
 __slab_free+0x290/0x380 mm/slub.c:4483
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4119 [inline]
 slab_alloc_node mm/slub.c:4168 [inline]
 __do_kmalloc_node mm/slub.c:4297 [inline]
 __kmalloc_noprof+0x236/0x4c0 mm/slub.c:4310
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1037 [inline]
 tomoyo_encode2 security/tomoyo/realpath.c:45 [inline]
 tomoyo_encode+0x26f/0x540 security/tomoyo/realpath.c:80
 tomoyo_mount_acl security/tomoyo/mount.c:150 [inline]
 tomoyo_mount_permission+0x53d/0xb80 security/tomoyo/mount.c:237
 security_sb_mount+0xe0/0x2f0 security/security.c:1564
 path_mount+0xb9/0xfa0 fs/namespace.c:3776
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88805cc85480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88805cc85500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805cc85580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff88805cc85600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805cc85680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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