==================================================================
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+0x10d3/0x10f0 net/ipv6/ip6_gre.c:925
Read of size 8 at addr ffff88804b8fcfdc by task syz.3.2404/10952

CPU: 2 UID: 0 PID: 10952 Comm: syz.3.2404 Not tainted 6.14.0-rc2-syzkaller-00228-g04f41cbf03ec #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:489
 kasan_report+0xd9/0x110 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+0x10d3/0x10f0 net/ipv6/ip6_gre.c:925
 __netdev_start_xmit include/linux/netdevice.h:5150 [inline]
 netdev_start_xmit include/linux/netdevice.h:5159 [inline]
 xmit_one net/core/dev.c:3735 [inline]
 dev_hard_start_xmit+0x9a/0x7b0 net/core/dev.c:3751
 sch_direct_xmit+0x1ae/0xc30 net/sched/sch_generic.c:343
 __dev_xmit_skb net/core/dev.c:3974 [inline]
 __dev_queue_xmit+0x13d4/0x43e0 net/core/dev.c:4550
 dev_queue_xmit include/linux/netdevice.h:3311 [inline]
 packet_xmit+0x23e/0x360 net/packet/af_packet.c:276
 packet_snd net/packet/af_packet.c:3132 [inline]
 packet_sendmsg+0x272b/0x56c0 net/packet/af_packet.c:3164
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:733 [inline]
 __sys_sendto+0x488/0x4f0 net/socket.c:2187
 __do_sys_sendto net/socket.c:2194 [inline]
 __se_sys_sendto net/socket.c:2190 [inline]
 __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2190
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9253f8cde9
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:00007f9254e00038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f92541a6080 RCX: 00007f9253f8cde9
RDX: 0000000000000028 RSI: 0000400000000180 RDI: 0000000000000004
RBP: 00007f925400e2a0 R08: 0000400000000140 R09: 0000000000000014
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f92541a6080 R15: 00007ffeb469b1a8
 </TASK>

Allocated by task 10952:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4115 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 kmem_cache_alloc_node_noprof+0x223/0x3c0 mm/slub.c:4216
 kmalloc_reserve+0x18b/0x2c0 net/core/skbuff.c:587
 __alloc_skb+0x164/0x380 net/core/skbuff.c:678
 alloc_skb include/linux/skbuff.h:1331 [inline]
 alloc_skb_with_frags+0xe4/0x850 net/core/skbuff.c:6612
 sock_alloc_send_pskb+0x7f1/0x980 net/core/sock.c:2897
 packet_alloc_skb net/packet/af_packet.c:2981 [inline]
 packet_snd net/packet/af_packet.c:3075 [inline]
 packet_sendmsg+0x1fd3/0x56c0 net/packet/af_packet.c:3164
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:733 [inline]
 __sys_sendto+0x488/0x4f0 net/socket.c:2187
 __do_sys_sendto net/socket.c:2194 [inline]
 __se_sys_sendto net/socket.c:2190 [inline]
 __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2190
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 10952:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 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:4609 [inline]
 kmem_cache_free+0x2e2/0x4d0 mm/slub.c:4711
 skb_kfree_head net/core/skbuff.c:1084 [inline]
 skb_kfree_head net/core/skbuff.c:1081 [inline]
 skb_free_head+0x18a/0x1d0 net/core/skbuff.c:1098
 skb_release_data+0x560/0x730 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+0x129/0x1a0 net/core/skbuff.c:1242
 packet_rcv+0x16c/0x15a0 net/packet/af_packet.c:2277
 dev_queue_xmit_nit+0x89f/0xbc0 net/core/dev.c:2492
 xmit_one net/core/dev.c:3731 [inline]
 dev_hard_start_xmit+0x283/0x7b0 net/core/dev.c:3751
 sch_direct_xmit+0x1ae/0xc30 net/sched/sch_generic.c:343
 __dev_xmit_skb net/core/dev.c:3974 [inline]
 __dev_queue_xmit+0x13d4/0x43e0 net/core/dev.c:4550
 dev_queue_xmit include/linux/netdevice.h:3311 [inline]
 packet_xmit+0x23e/0x360 net/packet/af_packet.c:276
 packet_snd net/packet/af_packet.c:3132 [inline]
 packet_sendmsg+0x272b/0x56c0 net/packet/af_packet.c:3164
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:733 [inline]
 __sys_sendto+0x488/0x4f0 net/socket.c:2187
 __do_sys_sendto net/socket.c:2194 [inline]
 __se_sys_sendto net/socket.c:2190 [inline]
 __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2190
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88804b8fcf00
 which belongs to the cache skbuff_small_head of size 640
The buggy address is located 220 bytes inside of
 freed 640-byte region [ffff88804b8fcf00, ffff88804b8fd180)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4b8fc
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801bfb4b40 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080150015 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801bfb4b40 dead000000000100 dead000000000122
head: 0000000000000000 0000000080150015 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea00012e3f01 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 10767, tgid 10766 (syz.2.2317), ts 87339163195, free_ts 56062643167
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1551
 prep_new_page mm/page_alloc.c:1559 [inline]
 get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3477
 __alloc_frozen_pages_noprof+0x221/0x2470 mm/page_alloc.c:4739
 alloc_pages_mpol+0x1fc/0x540 mm/mempolicy.c:2270
 alloc_slab_page mm/slub.c:2423 [inline]
 allocate_slab mm/slub.c:2587 [inline]
 new_slab+0x23d/0x330 mm/slub.c:2640
 ___slab_alloc+0xc5d/0x1720 mm/slub.c:3826
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3916
 __slab_alloc_node mm/slub.c:3991 [inline]
 slab_alloc_node mm/slub.c:4152 [inline]
 kmem_cache_alloc_node_noprof+0xfc/0x3c0 mm/slub.c:4216
 kmalloc_reserve+0x18b/0x2c0 net/core/skbuff.c:587
 __alloc_skb+0x164/0x380 net/core/skbuff.c:678
 alloc_skb include/linux/skbuff.h:1331 [inline]
 alloc_skb_with_frags+0xe4/0x850 net/core/skbuff.c:6612
 sock_alloc_send_pskb+0x7f1/0x980 net/core/sock.c:2897
 packet_alloc_skb net/packet/af_packet.c:2981 [inline]
 packet_snd net/packet/af_packet.c:3075 [inline]
 packet_sendmsg+0x1fd3/0x56c0 net/packet/af_packet.c:3164
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:733 [inline]
 __sys_sendto+0x488/0x4f0 net/socket.c:2187
 __do_sys_sendto net/socket.c:2194 [inline]
 __se_sys_sendto net/socket.c:2190 [inline]
 __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2190
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
page last free pid 6023 tgid 6023 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_frozen_pages+0x6db/0xfb0 mm/page_alloc.c:2660
 vfree+0x174/0x950 mm/vmalloc.c:3383
 kcov_put kernel/kcov.c:439 [inline]
 kcov_put+0x2a/0x40 kernel/kcov.c:435
 kcov_close+0xd/0x20 kernel/kcov.c:535
 __fput+0x3ff/0xb70 fs/file_table.c:464
 task_work_run+0x14e/0x250 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0xad8/0x2d70 kernel/exit.c:938
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1087
 get_signal+0x24ed/0x26c0 kernel/signal.c:3036
 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88804b8fce80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88804b8fcf00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88804b8fcf80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff88804b8fd000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88804b8fd080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================