==================================================================
BUG: KASAN: use-after-free in __nft_trace_packet+0x135/0x150 net/netfilter/nf_tables_core.c:30
Read of size 2 at addr ffff888074d601c0 by task syz.2.140/4748

CPU: 1 PID: 4748 Comm: syz.2.140 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]
 ip_finish_output2+0xd50/0x10a0 net/ipv4/ip_output.c:229
 dst_output include/net/dst.h:452 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 __ip_queue_xmit+0x11c1/0x1c00 net/ipv4/ip_output.c:532
 __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_v4_connect+0x103e/0x1a80 net/ipv4/tcp_ipv4.c:323
 __inet_stream_connect+0x244/0xd70 net/ipv4/af_inet.c:672
 inet_stream_connect+0x62/0xa0 net/ipv4/af_inet.c:736
 __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: 0033:0x7f87a71d6eb9
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:00007f87a5432028 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f87a7451fa0 RCX: 00007f87a71d6eb9
RDX: 0000000000000010 RSI: 0000200000000180 RDI: 0000000000000003
RBP: 00007f87a7244c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f87a7452038 R14: 00007f87a7451fa0 R15: 00007fffb712cd18
 </TASK>

Allocated by task 4748:
 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+0x16f/0xde0 net/netfilter/nf_synproxy_core.c:482
 nft_synproxy_eval_v4+0x347/0x4e0 net/netfilter/nft_synproxy.c:59
 nft_synproxy_do_eval+0x304/0x570 net/netfilter/nft_synproxy.c:141
 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]
 ip_finish_output2+0xd50/0x10a0 net/ipv4/ip_output.c:229
 dst_output include/net/dst.h:452 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 __ip_queue_xmit+0x11c1/0x1c00 net/ipv4/ip_output.c:532
 __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_v4_connect+0x103e/0x1a80 net/ipv4/tcp_ipv4.c:323
 __inet_stream_connect+0x244/0xd70 net/ipv4/af_inet.c:672
 inet_stream_connect+0x62/0xa0 net/ipv4/af_inet.c:736
 __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 4748:
 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_v4+0x34f/0x4e0 net/netfilter/nft_synproxy.c:60
 nft_synproxy_do_eval+0x304/0x570 net/netfilter/nft_synproxy.c:141
 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]
 ip_finish_output2+0xd50/0x10a0 net/ipv4/ip_output.c:229
 dst_output include/net/dst.h:452 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 __ip_queue_xmit+0x11c1/0x1c00 net/ipv4/ip_output.c:532
 __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_v4_connect+0x103e/0x1a80 net/ipv4/tcp_ipv4.c:323
 __inet_stream_connect+0x244/0xd70 net/ipv4/af_inet.c:672
 inet_stream_connect+0x62/0xa0 net/ipv4/af_inet.c:736
 __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 ffff888074d60140
 which belongs to the cache skbuff_head_cache of size 232
The buggy address is located 128 bytes inside of
 232-byte region [ffff888074d60140, ffff888074d60228)
The buggy address belongs to the page:
page:ffffea0001d35800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x74d60
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea00007ecd80 0000000b00000002 ffff888144bf0140
raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 4194, ts 71852372906, free_ts 71756445456
 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]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:664 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:721 [inline]
 nsim_dev_trap_report_work+0x2a1/0xb40 drivers/net/netdevsim/dev.c:762
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
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_list+0x119/0x820 mm/page_alloc.c:3433
 release_pages+0x186c/0x1be0 mm/swap.c:963
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu mm/mmu_gather.c:247 [inline]
 tlb_finish_mmu+0x176/0x300 mm/mmu_gather.c:338
 exit_mmap+0x3d0/0x640 mm/mmap.c:3218
 __mmput+0x115/0x3b0 kernel/fork.c:1127
 exit_mm+0x588/0x6e0 kernel/exit.c:550
 do_exit+0x5a9/0x20c0 kernel/exit.c:870
 do_group_exit+0x12e/0x300 kernel/exit.c:997
 get_signal+0x6ca/0x12c0 kernel/signal.c:2900
 arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff888074d60080: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc
 ffff888074d60100: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
>ffff888074d60180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888074d60200: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
 ffff888074d60280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================