GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
==================================================================
BUG: KASAN: use-after-free in __nft_trace_packet+0x135/0x150 net/netfilter/nf_tables_core.c:30
Read of size 2 at addr ffff88801fb64300 by task syz.5.1149/7702

CPU: 1 PID: 7702 Comm: syz.5.1149 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 __nft_trace_packet+0x135/0x150 net/netfilter/nf_tables_core.c:30
 nft_trace_verdict net/netfilter/nf_tables_core.c:110 [inline]
 nft_do_chain+0x12a5/0x14f0 net/netfilter/nf_tables_core.c:256
 nft_do_chain_inet+0x25c/0x340 net/netfilter/nft_chain_filter.c:161
 nf_hook_entry_hookfn include/linux/netfilter.h:142 [inline]
 nf_hook_slow+0xb9/0x200 net/netfilter/core.c:584
 nf_hook include/linux/netfilter.h:257 [inline]
 NF_HOOK+0x1f2/0x390 include/linux/netfilter.h:300
 NF_HOOK+0x303/0x390 include/linux/netfilter.h:302
 __netif_receive_skb_one_core net/core/dev.c:5525 [inline]
 __netif_receive_skb+0xcc/0x290 net/core/dev.c:5639
 process_backlog+0x370/0x790 net/core/dev.c:6516
 __napi_poll+0xc0/0x430 net/core/dev.c:7075
 napi_poll net/core/dev.c:7142 [inline]
 net_rx_action+0x4d4/0xa10 net/core/dev.c:7232
 handle_softirqs+0x339/0x830 kernel/softirq.c:576
 do_softirq+0x142/0x210 kernel/softirq.c:477
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x180/0x1c0 kernel/softirq.c:401
 rcu_read_unlock_bh include/linux/rcupdate.h:810 [inline]
 ip6_finish_output2+0x1127/0x1510 net/ipv6/ip6_output.c:131
 dst_output include/net/dst.h:452 [inline]
 NF_HOOK include/linux/netfilter.h:302 [inline]
 ip6_xmit+0x109b/0x16d0 net/ipv6/ip6_output.c:338
 inet6_csk_xmit+0x405/0x680 net/ipv6/inet6_connection_sock.c:135
 __tcp_transmit_skb+0x1d11/0x3200 net/ipv4/tcp_output.c:1404
 tcp_transmit_skb net/ipv4/tcp_output.c:1422 [inline]
 tcp_connect+0x21ac/0x4970 net/ipv4/tcp_output.c:3904
 tcp_v6_connect+0x1224/0x1a30 net/ipv6/tcp_ipv6.c:337
 __inet_stream_connect+0x244/0xd70 net/ipv4/af_inet.c:672
 inet_stream_connect+0x62/0xa0 net/ipv4/af_inet.c:736
 mptcp_stream_connect+0x674/0x950 net/mptcp/protocol.c:3481
 __sys_connect_file net/socket.c:1932 [inline]
 __sys_connect+0x3cb/0x450 net/socket.c:1949
 __do_sys_connect net/socket.c:1959 [inline]
 __se_sys_connect net/socket.c:1956 [inline]
 __x64_sys_connect+0x76/0x80 net/socket.c:1956
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fe2c6f3feb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe2c519b028 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007fe2c71bafa0 RCX: 00007fe2c6f3feb9
RDX: 000000000000001c RSI: 0000200000000040 RDI: 0000000000000003
RBP: 00007fe2c6fadc1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe2c71bb038 R14: 00007fe2c71bafa0 R15: 00007ffe32d50ce8
 </TASK>

Allocated by task 7702:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 __kasan_slab_alloc+0x9c/0xd0 mm/kasan/common.c:467
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3225 [inline]
 kmem_cache_alloc_node+0x12d/0x2d0 mm/slub.c:3261
 __alloc_skb+0xf4/0x750 net/core/skbuff.c:415
 alloc_skb include/linux/skbuff.h:1162 [inline]
 synproxy_send_client_synack_ipv6+0x161/0xc60 net/netfilter/nf_synproxy_core.c:895
 nft_synproxy_eval_v6+0x347/0x4e0 net/netfilter/nft_synproxy.c:90
 nft_synproxy_do_eval+0x3c9/0x570 net/netfilter/nft_synproxy.c:145
 expr_call_ops_eval net/netfilter/nf_tables_core.c:198 [inline]
 nft_do_chain+0x48c/0x14f0 net/netfilter/nf_tables_core.c:238
 nft_do_chain_inet+0x25c/0x340 net/netfilter/nft_chain_filter.c:161
 nf_hook_entry_hookfn include/linux/netfilter.h:142 [inline]
 nf_hook_slow+0xb9/0x200 net/netfilter/core.c:584
 nf_hook include/linux/netfilter.h:257 [inline]
 NF_HOOK+0x1f2/0x390 include/linux/netfilter.h:300
 NF_HOOK+0x303/0x390 include/linux/netfilter.h:302
 __netif_receive_skb_one_core net/core/dev.c:5525 [inline]
 __netif_receive_skb+0xcc/0x290 net/core/dev.c:5639
 process_backlog+0x370/0x790 net/core/dev.c:6516
 __napi_poll+0xc0/0x430 net/core/dev.c:7075
 napi_poll net/core/dev.c:7142 [inline]
 net_rx_action+0x4d4/0xa10 net/core/dev.c:7232
 handle_softirqs+0x339/0x830 kernel/softirq.c:576
 do_softirq+0x142/0x210 kernel/softirq.c:477
 __local_bh_enable_ip+0x180/0x1c0 kernel/softirq.c:401
 rcu_read_unlock_bh include/linux/rcupdate.h:810 [inline]
 ip6_finish_output2+0x1127/0x1510 net/ipv6/ip6_output.c:131
 dst_output include/net/dst.h:452 [inline]
 NF_HOOK include/linux/netfilter.h:302 [inline]
 ip6_xmit+0x109b/0x16d0 net/ipv6/ip6_output.c:338
 inet6_csk_xmit+0x405/0x680 net/ipv6/inet6_connection_sock.c:135
 __tcp_transmit_skb+0x1d11/0x3200 net/ipv4/tcp_output.c:1404
 tcp_transmit_skb net/ipv4/tcp_output.c:1422 [inline]
 tcp_connect+0x21ac/0x4970 net/ipv4/tcp_output.c:3904
 tcp_v6_connect+0x1224/0x1a30 net/ipv6/tcp_ipv6.c:337
 __inet_stream_connect+0x244/0xd70 net/ipv4/af_inet.c:672
 inet_stream_connect+0x62/0xa0 net/ipv4/af_inet.c:736
 mptcp_stream_connect+0x674/0x950 net/mptcp/protocol.c:3481
 __sys_connect_file net/socket.c:1932 [inline]
 __sys_connect+0x3cb/0x450 net/socket.c:1949
 __do_sys_connect net/socket.c:1959 [inline]
 __se_sys_connect net/socket.c:1956 [inline]
 __x64_sys_connect+0x76/0x80 net/socket.c:1956
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Freed by task 7702:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kmem_cache_free+0x8f/0x210 mm/slub.c:3520
 nft_synproxy_eval_v6+0x34f/0x4e0 net/netfilter/nft_synproxy.c:91
 nft_synproxy_do_eval+0x3c9/0x570 net/netfilter/nft_synproxy.c:145
 expr_call_ops_eval net/netfilter/nf_tables_core.c:198 [inline]
 nft_do_chain+0x48c/0x14f0 net/netfilter/nf_tables_core.c:238
 nft_do_chain_inet+0x25c/0x340 net/netfilter/nft_chain_filter.c:161
 nf_hook_entry_hookfn include/linux/netfilter.h:142 [inline]
 nf_hook_slow+0xb9/0x200 net/netfilter/core.c:584
 nf_hook include/linux/netfilter.h:257 [inline]
 NF_HOOK+0x1f2/0x390 include/linux/netfilter.h:300
 NF_HOOK+0x303/0x390 include/linux/netfilter.h:302
 __netif_receive_skb_one_core net/core/dev.c:5525 [inline]
 __netif_receive_skb+0xcc/0x290 net/core/dev.c:5639
 process_backlog+0x370/0x790 net/core/dev.c:6516
 __napi_poll+0xc0/0x430 net/core/dev.c:7075
 napi_poll net/core/dev.c:7142 [inline]
 net_rx_action+0x4d4/0xa10 net/core/dev.c:7232
 handle_softirqs+0x339/0x830 kernel/softirq.c:576
 do_softirq+0x142/0x210 kernel/softirq.c:477
 __local_bh_enable_ip+0x180/0x1c0 kernel/softirq.c:401
 rcu_read_unlock_bh include/linux/rcupdate.h:810 [inline]
 ip6_finish_output2+0x1127/0x1510 net/ipv6/ip6_output.c:131
 dst_output include/net/dst.h:452 [inline]
 NF_HOOK include/linux/netfilter.h:302 [inline]
 ip6_xmit+0x109b/0x16d0 net/ipv6/ip6_output.c:338
 inet6_csk_xmit+0x405/0x680 net/ipv6/inet6_connection_sock.c:135
 __tcp_transmit_skb+0x1d11/0x3200 net/ipv4/tcp_output.c:1404
 tcp_transmit_skb net/ipv4/tcp_output.c:1422 [inline]
 tcp_connect+0x21ac/0x4970 net/ipv4/tcp_output.c:3904
 tcp_v6_connect+0x1224/0x1a30 net/ipv6/tcp_ipv6.c:337
 __inet_stream_connect+0x244/0xd70 net/ipv4/af_inet.c:672
 inet_stream_connect+0x62/0xa0 net/ipv4/af_inet.c:736
 mptcp_stream_connect+0x674/0x950 net/mptcp/protocol.c:3481
 __sys_connect_file net/socket.c:1932 [inline]
 __sys_connect+0x3cb/0x450 net/socket.c:1949
 __do_sys_connect net/socket.c:1959 [inline]
 __se_sys_connect net/socket.c:1956 [inline]
 __x64_sys_connect+0x76/0x80 net/socket.c:1956
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff88801fb64280
 which belongs to the cache skbuff_head_cache of size 232
The buggy address is located 128 bytes inside of
 232-byte region [ffff88801fb64280, ffff88801fb64368)
The buggy address belongs to the page:
page:ffffea00007ed900 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1fb64
memcg:ffff888022752181
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 dead000000000100 dead000000000122 ffff88801bbe5140
raw: 0000000000000000 00000000800c000c 00000001ffffffff ffff888022752181
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 3854, ts 42966412804, free_ts 42938718994
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1bbd/0x1ca0 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5487
 alloc_slab_page mm/slub.c:1780 [inline]
 allocate_slab mm/slub.c:1917 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1980
 ___slab_alloc+0x80a/0xdd0 mm/slub.c:3013
 __slab_alloc mm/slub.c:3100 [inline]
 slab_alloc_node mm/slub.c:3191 [inline]
 kmem_cache_alloc_node+0x1c3/0x2d0 mm/slub.c:3261
 __alloc_skb+0xf4/0x750 net/core/skbuff.c:415
 alloc_skb include/linux/skbuff.h:1162 [inline]
 alloc_skb_with_frags+0xa7/0x730 net/core/skbuff.c:6170
 sock_alloc_send_pskb+0x87f/0x9a0 net/core/sock.c:2536
 unix_dgram_sendmsg+0x5fc/0x18a0 net/unix/af_unix.c:1809
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 sock_write_iter+0x2a6/0x3a0 net/socket.c:1089
 do_iter_readv_writev+0x47e/0x5f0 fs/read_write.c:-1
 do_iter_write+0x205/0x7b0 fs/read_write.c:855
 vfs_writev fs/read_write.c:928 [inline]
 do_writev+0x281/0x480 fs/read_write.c:971
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page+0x8f/0x2a0 mm/page_alloc.c:3396
 mm_free_pgd kernel/fork.c:653 [inline]
 __mmdrop+0xaa/0x3e0 kernel/fork.c:704
 mmdrop include/linux/sched/mm.h:49 [inline]
 finish_task_switch+0x215/0x640 kernel/sched/core.c:4948
 context_switch kernel/sched/core.c:5052 [inline]
 __schedule+0x11f7/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:1890
 __skb_wait_for_more_packets+0x3a8/0x590 net/core/datagram.c:122
 __unix_dgram_recvmsg+0x2ad/0xd90 net/unix/af_unix.c:2328
 sock_recvmsg_nosec net/socket.c:968 [inline]
 sock_recvmsg net/socket.c:986 [inline]
 sock_read_iter+0x2b8/0x380 net/socket.c:1067
 call_read_iter include/linux/fs.h:2167 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x759/0xd60 fs/read_write.c:485
 ksys_read+0x152/0x260 fs/read_write.c:623
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff88801fb64200: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
 ffff88801fb64280: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801fb64300: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
                   ^
 ffff88801fb64380: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff88801fb64400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================