TC_ACT_REPEAT abuse ? ===================================================== BUG: KMSAN: uninit-value in __skb_flow_dissect+0x2022/0xa1f0 net/core/flow_dissector.c:1198 __skb_flow_dissect+0x2022/0xa1f0 net/core/flow_dissector.c:1198 skb_flow_dissect_flow_keys include/linux/skbuff.h:1612 [inline] cake_hash net/sched/sch_cake.c:724 [inline] cake_classify net/sched/sch_cake.c:1747 [inline] cake_enqueue+0x1149/0xf750 net/sched/sch_cake.c:1765 dev_qdisc_enqueue net/core/dev.c:4168 [inline] __dev_xmit_skb net/core/dev.c:4283 [inline] __dev_queue_xmit+0x25ad/0x5980 net/core/dev.c:4819 dev_queue_xmit include/linux/netdevice.h:3385 [inline] packet_xmit+0x8f/0x710 net/packet/af_packet.c:275 packet_snd net/packet/af_packet.c:3076 [inline] packet_sendmsg+0x91d9/0xa320 net/packet/af_packet.c:3108 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xf37/0xfd0 net/socket.c:2592 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2681 x64_sys_call+0x1e20/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was stored to memory at: skb_data_move+0x3b4/0x4f0 include/linux/skbuff.h:-1 skb_postpush_data_move include/linux/skbuff.h:4652 [inline] __vlan_insert_inner_tag include/linux/if_vlan.h:368 [inline] __vlan_insert_tag include/linux/if_vlan.h:407 [inline] skb_vlan_push+0x647/0xb70 net/core/skbuff.c:6475 tcf_vlan_act+0xc09/0x12c0 net/sched/act_vlan.c:49 tc_act include/net/tc_wrapper.h:130 [inline] tcf_action_exec+0x21f/0x1190 net/sched/act_api.c:1152 tcf_exts_exec include/net/pkt_cls.h:349 [inline] mall_classify+0x183/0x290 net/sched/cls_matchall.c:42 tc_classify include/net/tc_wrapper.h:197 [inline] __tcf_classify net/sched/cls_api.c:1764 [inline] tcf_classify+0x855/0x1ca0 net/sched/cls_api.c:1860 cake_classify net/sched/sch_cake.c:1726 [inline] cake_enqueue+0x16b/0xf750 net/sched/sch_cake.c:1765 dev_qdisc_enqueue net/core/dev.c:4168 [inline] __dev_xmit_skb net/core/dev.c:4283 [inline] __dev_queue_xmit+0x25ad/0x5980 net/core/dev.c:4819 dev_queue_xmit include/linux/netdevice.h:3385 [inline] packet_xmit+0x8f/0x710 net/packet/af_packet.c:275 packet_snd net/packet/af_packet.c:3076 [inline] packet_sendmsg+0x91d9/0xa320 net/packet/af_packet.c:3108 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xf37/0xfd0 net/socket.c:2592 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2681 x64_sys_call+0x1e20/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was stored to memory at: skb_data_move+0x3b4/0x4f0 include/linux/skbuff.h:-1 skb_postpush_data_move include/linux/skbuff.h:4652 [inline] __vlan_insert_inner_tag include/linux/if_vlan.h:368 [inline] __vlan_insert_tag include/linux/if_vlan.h:407 [inline] skb_vlan_push+0x647/0xb70 net/core/skbuff.c:6475 tcf_vlan_act+0xc09/0x12c0 net/sched/act_vlan.c:49 tc_act include/net/tc_wrapper.h:130 [inline] tcf_action_exec+0x21f/0x1190 net/sched/act_api.c:1152 tcf_exts_exec include/net/pkt_cls.h:349 [inline] mall_classify+0x183/0x290 net/sched/cls_matchall.c:42 tc_classify include/net/tc_wrapper.h:197 [inline] __tcf_classify net/sched/cls_api.c:1764 [inline] tcf_classify+0x855/0x1ca0 net/sched/cls_api.c:1860 cake_classify net/sched/sch_cake.c:1726 [inline] cake_enqueue+0x16b/0xf750 net/sched/sch_cake.c:1765 dev_qdisc_enqueue net/core/dev.c:4168 [inline] __dev_xmit_skb net/core/dev.c:4283 [inline] __dev_queue_xmit+0x25ad/0x5980 net/core/dev.c:4819 dev_queue_xmit include/linux/netdevice.h:3385 [inline] packet_xmit+0x8f/0x710 net/packet/af_packet.c:275 packet_snd net/packet/af_packet.c:3076 [inline] packet_sendmsg+0x91d9/0xa320 net/packet/af_packet.c:3108 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xf37/0xfd0 net/socket.c:2592 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2681 x64_sys_call+0x1e20/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was stored to memory at: pskb_expand_head+0x4a0/0x1fb0 net/core/skbuff.c:2323 __skb_cow include/linux/skbuff.h:3854 [inline] skb_cow_head include/linux/skbuff.h:3888 [inline] __vlan_insert_inner_tag include/linux/if_vlan.h:361 [inline] __vlan_insert_tag include/linux/if_vlan.h:407 [inline] skb_vlan_push+0x444/0xb70 net/core/skbuff.c:6475 tcf_vlan_act+0xc09/0x12c0 net/sched/act_vlan.c:49 tc_act include/net/tc_wrapper.h:130 [inline] tcf_action_exec+0x21f/0x1190 net/sched/act_api.c:1152 tcf_exts_exec include/net/pkt_cls.h:349 [inline] mall_classify+0x183/0x290 net/sched/cls_matchall.c:42 tc_classify include/net/tc_wrapper.h:197 [inline] __tcf_classify net/sched/cls_api.c:1764 [inline] tcf_classify+0x855/0x1ca0 net/sched/cls_api.c:1860 cake_classify net/sched/sch_cake.c:1726 [inline] cake_enqueue+0x16b/0xf750 net/sched/sch_cake.c:1765 dev_qdisc_enqueue net/core/dev.c:4168 [inline] __dev_xmit_skb net/core/dev.c:4283 [inline] __dev_queue_xmit+0x25ad/0x5980 net/core/dev.c:4819 dev_queue_xmit include/linux/netdevice.h:3385 [inline] packet_xmit+0x8f/0x710 net/packet/af_packet.c:275 packet_snd net/packet/af_packet.c:3076 [inline] packet_sendmsg+0x91d9/0xa320 net/packet/af_packet.c:3108 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xf37/0xfd0 net/socket.c:2592 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2681 x64_sys_call+0x1e20/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was stored to memory at: skb_data_move+0x3b4/0x4f0 include/linux/skbuff.h:-1 skb_postpush_data_move include/linux/skbuff.h:4652 [inline] __vlan_insert_inner_tag include/linux/if_vlan.h:368 [inline] __vlan_insert_tag include/linux/if_vlan.h:407 [inline] skb_vlan_push+0x647/0xb70 net/core/skbuff.c:6475 tcf_vlan_act+0xc09/0x12c0 net/sched/act_vlan.c:49 tc_act include/net/tc_wrapper.h:130 [inline] tcf_action_exec+0x21f/0x1190 net/sched/act_api.c:1152 tcf_exts_exec include/net/pkt_cls.h:349 [inline] mall_classify+0x183/0x290 net/sched/cls_matchall.c:42 tc_classify include/net/tc_wrapper.h:197 [inline] __tcf_classify net/sched/cls_api.c:1764 [inline] tcf_classify+0x855/0x1ca0 net/sched/cls_api.c:1860 cake_classify net/sched/sch_cake.c:1726 [inline] cake_enqueue+0x16b/0xf750 net/sched/sch_cake.c:1765 dev_qdisc_enqueue net/core/dev.c:4168 [inline] __dev_xmit_skb net/core/dev.c:4283 [inline] __dev_queue_xmit+0x25ad/0x5980 net/core/dev.c:4819 dev_queue_xmit include/linux/netdevice.h:3385 [inline] packet_xmit+0x8f/0x710 net/packet/af_packet.c:275 packet_snd net/packet/af_packet.c:3076 [inline] packet_sendmsg+0x91d9/0xa320 net/packet/af_packet.c:3108 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xf37/0xfd0 net/socket.c:2592 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2681 x64_sys_call+0x1e20/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was stored to memory at: skb_data_move+0x3b4/0x4f0 include/linux/skbuff.h:-1 skb_postpush_data_move include/linux/skbuff.h:4652 [inline] __vlan_insert_inner_tag include/linux/if_vlan.h:368 [inline] __vlan_insert_tag include/linux/if_vlan.h:407 [inline] skb_vlan_push+0x647/0xb70 net/core/skbuff.c:6475 tcf_vlan_act+0xc09/0x12c0 net/sched/act_vlan.c:49 tc_act include/net/tc_wrapper.h:130 [inline] tcf_action_exec+0x21f/0x1190 net/sched/act_api.c:1152 tcf_exts_exec include/net/pkt_cls.h:349 [inline] mall_classify+0x183/0x290 net/sched/cls_matchall.c:42 tc_classify include/net/tc_wrapper.h:197 [inline] __tcf_classify net/sched/cls_api.c:1764 [inline] tcf_classify+0x855/0x1ca0 net/sched/cls_api.c:1860 cake_classify net/sched/sch_cake.c:1726 [inline] cake_enqueue+0x16b/0xf750 net/sched/sch_cake.c:1765 dev_qdisc_enqueue net/core/dev.c:4168 [inline] __dev_xmit_skb net/core/dev.c:4283 [inline] __dev_queue_xmit+0x25ad/0x5980 net/core/dev.c:4819 dev_queue_xmit include/linux/netdevice.h:3385 [inline] packet_xmit+0x8f/0x710 net/packet/af_packet.c:275 packet_snd net/packet/af_packet.c:3076 [inline] packet_sendmsg+0x91d9/0xa320 net/packet/af_packet.c:3108 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xf37/0xfd0 net/socket.c:2592 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2681 x64_sys_call+0x1e20/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was stored to memory at: skb_data_move+0x3b4/0x4f0 include/linux/skbuff.h:-1 skb_postpush_data_move include/linux/skbuff.h:4652 [inline] __vlan_insert_inner_tag include/linux/if_vlan.h:368 [inline] __vlan_insert_tag include/linux/if_vlan.h:407 [inline] skb_vlan_push+0x647/0xb70 net/core/skbuff.c:6475 tcf_vlan_act+0xc09/0x12c0 net/sched/act_vlan.c:49 tc_act include/net/tc_wrapper.h:130 [inline] tcf_action_exec+0x21f/0x1190 net/sched/act_api.c:1152 tcf_exts_exec include/net/pkt_cls.h:349 [inline] mall_classify+0x183/0x290 net/sched/cls_matchall.c:42 tc_classify include/net/tc_wrapper.h:197 [inline] __tcf_classify net/sched/cls_api.c:1764 [inline] tcf_classify+0x855/0x1ca0 net/sched/cls_api.c:1860 cake_classify net/sched/sch_cake.c:1726 [inline] cake_enqueue+0x16b/0xf750 net/sched/sch_cake.c:1765 dev_qdisc_enqueue net/core/dev.c:4168 [inline] __dev_xmit_skb net/core/dev.c:4283 [inline] __dev_queue_xmit+0x25ad/0x5980 net/core/dev.c:4819 dev_queue_xmit include/linux/netdevice.h:3385 [inline] packet_xmit+0x8f/0x710 net/packet/af_packet.c:275 packet_snd net/packet/af_packet.c:3076 [inline] packet_sendmsg+0x91d9/0xa320 net/packet/af_packet.c:3108 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xf37/0xfd0 net/socket.c:2592 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2681 x64_sys_call+0x1e20/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was stored to memory at: skb_data_move+0x3b4/0x4f0 include/linux/skbuff.h:-1 skb_postpush_data_move include/linux/skbuff.h:4652 [inline] __vlan_insert_inner_tag include/linux/if_vlan.h:368 [inline] __vlan_insert_tag include/linux/if_vlan.h:407 [inline] skb_vlan_push+0x647/0xb70 net/core/skbuff.c:6475 tcf_vlan_act+0xc09/0x12c0 net/sched/act_vlan.c:49 tc_act include/net/tc_wrapper.h:130 [inline] tcf_action_exec+0x21f/0x1190 net/sched/act_api.c:1152 tcf_exts_exec include/net/pkt_cls.h:349 [inline] mall_classify+0x183/0x290 net/sched/cls_matchall.c:42 tc_classify include/net/tc_wrapper.h:197 [inline] __tcf_classify net/sched/cls_api.c:1764 [inline] tcf_classify+0x855/0x1ca0 net/sched/cls_api.c:1860 cake_classify net/sched/sch_cake.c:1726 [inline] cake_enqueue+0x16b/0xf750 net/sched/sch_cake.c:1765 dev_qdisc_enqueue net/core/dev.c:4168 [inline] __dev_xmit_skb net/core/dev.c:4283 [inline] __dev_queue_xmit+0x25ad/0x5980 net/core/dev.c:4819 dev_queue_xmit include/linux/netdevice.h:3385 [inline] packet_xmit+0x8f/0x710 net/packet/af_packet.c:275 packet_snd net/packet/af_packet.c:3076 [inline] packet_sendmsg+0x91d9/0xa320 net/packet/af_packet.c:3108 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xf37/0xfd0 net/socket.c:2592 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2681 x64_sys_call+0x1e20/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was created at: slab_post_alloc_hook mm/slub.c:4545 [inline] slab_alloc_node mm/slub.c:4866 [inline] kmem_cache_alloc_node_noprof+0x3cd/0x12d0 mm/slub.c:4918 kmalloc_reserve net/core/skbuff.c:613 [inline] __alloc_skb+0x855/0x1190 net/core/skbuff.c:713 alloc_skb include/linux/skbuff.h:1383 [inline] alloc_skb_with_frags+0xc5/0xa60 net/core/skbuff.c:6763 sock_alloc_send_pskb+0xacb/0xc60 net/core/sock.c:2995 packet_alloc_skb net/packet/af_packet.c:2926 [inline] packet_snd net/packet/af_packet.c:3019 [inline] packet_sendmsg+0x7477/0xa320 net/packet/af_packet.c:3108 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xf37/0xfd0 net/socket.c:2592 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2681 x64_sys_call+0x1e20/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 0 UID: 0 PID: 6044 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 =====================================================