CVE-2025-21959: In the Linux kernel, the following vulnerability has been resolved:  netfilter: nf_conncount: Fully initialize struct nf_conncount_tuple in insert_tree()  Since commit b36e4523d4d5 ("netfilter: nf_conncount: fix garbage collection confirm race"), `cpu` and `jiffies32` were introduced to the struct nf_conncount_tuple.  The commit made nf_conncount_add() initialize `conn->cpu` and `conn->jiffies32` when allocating the struct. In contrast, count_tree() was not changed to initialize them.  By commit 34848d5c896e ("netfilter: nf_conncount: Split insert and traversal"), count_tree() was split and the relevant allocation code now resides in insert_tree(). Initialize `conn->cpu` and `conn->jiffies32` in insert_tree().  BUG: KMSAN: uninit-value in find_or_evict net/netfilter/nf_conncount.c:117 [inline] BUG: KMSAN: uninit-value in __nf_conncount_add+0xd9c/0x2850 net/netfilter/nf_conncount.c:143  find_or_evict net/netfilter/nf_conncount.c:117 [inline]  __nf_conncount_add+0xd9c/0x2850 net/netfilter/nf_conncount.c:143  count_tree net/netfilter/nf_conncount.c:438 [inline]  nf_conncount_count+0x82f/0x1e80 net/netfilter/nf_conncount.c:521  connlimit_mt+0x7f6/0xbd0 net/netfilter/xt_connlimit.c:72  __nft_match_eval net/netfilter/nft_compat.c:403 [inline]  nft_match_eval+0x1a5/0x300 net/netfilter/nft_compat.c:433  expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline]  nft_do_chain+0x426/0x2290 net/netfilter/nf_tables_core.c:288  nft_do_chain_ipv4+0x1a5/0x230 net/netfilter/nft_chain_filter.c:23  nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]  nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626  nf_hook_slow_list+0x24d/0x860 net/netfilter/core.c:663  NF_HOOK_LIST include/linux/netfilter.h:350 [inline]  ip_sublist_rcv+0x17b7/0x17f0 net/ipv4/ip_input.c:633  ip_list_rcv+0x9ef/0xa40 net/ipv4/ip_input.c:669  __netif_receive_skb_list_ptype net/core/dev.c:5936 [inline]  __netif_receive_skb_list_core+0x15c5/0x1670 net/core/dev.c:5983  __netif_receive_skb_list net/core/dev.c:6035 [inline]  netif_receive_skb_list_internal+0x1085/0x1700 net/core/dev.c:6126  netif_receive_skb_list+0x5a/0x460 net/core/dev.c:6178  xdp_recv_frames net/bpf/test_run.c:280 [inline]  xdp_test_run_batch net/bpf/test_run.c:361 [inline]  bpf_test_run_xdp_live+0x2e86/0x3480 net/bpf/test_run.c:390  bpf_prog_test_run_xdp+0xf1d/0x1ae0 net/bpf/test_run.c:1316  bpf_prog_test_run+0x5e5/0xa30 kernel/bpf/syscall.c:4407  __sys_bpf+0x6aa/0xd90 kernel/bpf/syscall.c:5813  __do_sys_bpf kernel/bpf/syscall.c:5902 [inline]  __se_sys_bpf kernel/bpf/syscall.c:5900 [inline]  __ia32_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5900  ia32_sys_call+0x394d/0x4180 arch/x86/include/generated/asm/syscalls_32.h:358  do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]  __do_fast_syscall_32+0xb0/0x110 arch/x86/entry/common.c:387  do_fast_syscall_32+0x38/0x80 arch/x86/entry/common.c:412  do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:450  entry_SYSENTER_compat_after_hwframe+0x84/0x8e  Uninit was created at:  slab_post_alloc_hook mm/slub.c:4121 [inline]  slab_alloc_node mm/slub.c:4164 [inline]  kmem_cache_alloc_noprof+0x915/0xe10 mm/slub.c:4171  insert_tree net/netfilter/nf_conncount.c:372 [inline]  count_tree net/netfilter/nf_conncount.c:450 [inline]  nf_conncount_count+0x1415/0x1e80 net/netfilter/nf_conncount.c:521  connlimit_mt+0x7f6/0xbd0 net/netfilter/xt_connlimit.c:72  __nft_match_eval net/netfilter/nft_compat.c:403 [inline]  nft_match_eval+0x1a5/0x300 net/netfilter/nft_compat.c:433  expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline]  nft_do_chain+0x426/0x2290 net/netfilter/nf_tables_core.c:288  nft_do_chain_ipv4+0x1a5/0x230 net/netfilter/nft_chain_filter.c:23  nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]  nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626  nf_hook_slow_list+0x24d/0x860 net/netfilter/core.c:663  NF_HOOK_LIST include/linux/netfilter.h:350 [inline]  ip_sublist_rcv+0x17b7/0x17f0 net/ipv4/ip_input.c:633  ip_list_rcv+0x9ef/0xa40 net/ip ---truncated---