================================================================== BUG: KASAN: use-after-free in __nft_trace_packet+0x135/0x150 net/netfilter/nf_tables_core.c:30 Read of size 2 at addr ffff8880602956c0 by task syz.3.22/4367 CPU: 1 PID: 4367 Comm: syz.3.22 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: 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+0x1299/0x14d0 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:5551 [inline] __netif_receive_skb+0xcc/0x290 net/core/dev.c:5665 netif_receive_skb_internal net/core/dev.c:5751 [inline] netif_receive_skb+0x19e/0x700 net/core/dev.c:5810 tun_rx_batched+0x606/0x760 drivers/net/tun.c:-1 tun_get_user+0x25bf/0x3b60 drivers/net/tun.c:1989 tun_chr_write_iter+0x112/0x1e0 drivers/net/tun.c:2019 call_write_iter include/linux/fs.h:2173 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x748/0xd70 fs/read_write.c:594 ksys_write+0x153/0x260 fs/read_write.c:647 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: 0033:0x7f4b968b790e Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08 RSP: 002b:00007f4b94b4efb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f4b94b4f6c0 RCX: 00007f4b968b790e RDX: 0000000000000036 RSI: 0000200000000180 RDI: 00000000000000c8 RBP: 00007f4b9698e024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4b96b7f038 R14: 00007f4b96b7efa0 R15: 00007fffb3cf5518 Allocated by task 4367: 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+0x92/0xc0 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] slab_alloc mm/slub.c:3233 [inline] kmem_cache_alloc+0x15d/0x280 mm/slub.c:3238 __build_skb+0x26/0x2e0 net/core/skbuff.c:241 build_skb+0x1e/0x160 net/core/skbuff.c:258 __tun_build_skb+0x32/0x240 drivers/net/tun.c:1589 tun_build_skb drivers/net/tun.c:1674 [inline] tun_get_user+0x1a0e/0x3b60 drivers/net/tun.c:1797 tun_chr_write_iter+0x112/0x1e0 drivers/net/tun.c:2019 call_write_iter include/linux/fs.h:2173 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x748/0xd70 fs/read_write.c:594 ksys_write+0x153/0x260 fs/read_write.c:647 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 4367: 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+0xec/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+0x367/0x4e0 net/netfilter/nft_synproxy.c:-1 nft_synproxy_do_eval+0x32e/0x550 net/netfilter/nft_synproxy.c:140 expr_call_ops_eval net/netfilter/nf_tables_core.c:198 [inline] nft_do_chain+0x491/0x14d0 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:5551 [inline] __netif_receive_skb+0xcc/0x290 net/core/dev.c:5665 netif_receive_skb_internal net/core/dev.c:5751 [inline] netif_receive_skb+0x19e/0x700 net/core/dev.c:5810 tun_rx_batched+0x606/0x760 drivers/net/tun.c:-1 tun_get_user+0x25bf/0x3b60 drivers/net/tun.c:1989 tun_chr_write_iter+0x112/0x1e0 drivers/net/tun.c:2019 call_write_iter include/linux/fs.h:2173 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x748/0xd70 fs/read_write.c:594 ksys_write+0x153/0x260 fs/read_write.c:647 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 ffff888060295640 which belongs to the cache skbuff_head_cache of size 232 The buggy address is located 128 bytes inside of 232-byte region [ffff888060295640, ffff888060295728) The buggy address belongs to the page: page:ffffea000180a540 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x60295 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea000180a500 0000000600000006 ffff88801bbe4140 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 4190, ts 65706543239, free_ts 23139718112 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501 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+0x807/0xdd0 mm/slub.c:3013 __slab_alloc mm/slub.c:3100 [inline] slab_alloc_node mm/slub.c:3191 [inline] kmem_cache_alloc_node+0x118/0x2c0 mm/slub.c:3261 __alloc_skb+0xf4/0x750 net/core/skbuff.c:415 alloc_skb include/linux/skbuff.h:1162 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1178 [inline] netlink_sendmsg+0x654/0xbe0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:706 [inline] __sock_sendmsg net/socket.c:718 [inline] __sys_sendto+0x46d/0x620 net/socket.c:2073 __do_sys_sendto net/socket.c:2085 [inline] __se_sys_sendto net/socket.c:2081 [inline] __x64_sys_sendto+0xda/0xf0 net/socket.c:2081 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 free_contig_range+0x96/0xf0 mm/page_alloc.c:9428 destroy_args+0xef/0xa00 mm/debug_vm_pgtable.c:1018 debug_vm_pgtable+0x321/0x380 mm/debug_vm_pgtable.c:1336 do_one_initcall+0x272/0x730 init/main.c:1315 do_initcall_level+0x13d/0x1f0 init/main.c:1388 do_initcalls+0x4b/0x90 init/main.c:1404 kernel_init_freeable+0x3d5/0x560 init/main.c:1628 kernel_init+0x19/0x1b0 init/main.c:1519 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Memory state around the buggy address: ffff888060295580: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc ffff888060295600: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb >ffff888060295680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888060295700: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc ffff888060295780: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================