From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/net/hotdata.h | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 include/net/hotdata.h (limited to 'include/net/hotdata.h') diff --git a/include/net/hotdata.h b/include/net/hotdata.h new file mode 100644 index 000000000..62534d1f3 --- /dev/null +++ b/include/net/hotdata.h @@ -0,0 +1,65 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _NET_HOTDATA_H +#define _NET_HOTDATA_H + +#include +#include +#include +#include +#ifdef CONFIG_RPS +#include +#endif + +struct skb_defer_node { + struct llist_head defer_list; + atomic_long_t defer_count; +} ____cacheline_aligned_in_smp; + +/* Read mostly data used in network fast paths. */ +struct net_hotdata { +#if IS_ENABLED(CONFIG_INET) + struct packet_offload ip_packet_offload; + struct net_offload tcpv4_offload; + struct net_protocol tcp_protocol; + struct net_offload udpv4_offload; + struct net_protocol udp_protocol; + struct packet_offload ipv6_packet_offload; + struct net_offload tcpv6_offload; +#if IS_ENABLED(CONFIG_IPV6) + struct inet6_protocol tcpv6_protocol; + struct inet6_protocol udpv6_protocol; +#endif + struct net_offload udpv6_offload; +#endif + struct list_head offload_base; + struct kmem_cache *skbuff_cache; + struct kmem_cache *skbuff_fclone_cache; + struct kmem_cache *skb_small_head_cache; +#ifdef CONFIG_RPS + rps_tag_ptr rps_sock_flow_table; + u32 rps_cpu_mask; +#endif + struct skb_defer_node __percpu *skb_defer_nodes; + int gro_normal_batch; + int netdev_budget; + int netdev_budget_usecs; + int tstamp_prequeue; + int max_backlog; + int qdisc_max_burst; + int dev_tx_weight; + int dev_rx_weight; + int sysctl_max_skb_frags; + int sysctl_skb_defer_max; + int sysctl_mem_pcpu_rsv; +}; + +#define inet_ehash_secret net_hotdata.tcp_protocol.secret +#define udp_ehash_secret net_hotdata.udp_protocol.secret +#define inet6_ehash_secret net_hotdata.tcpv6_protocol.secret +#define tcp_ipv6_hash_secret net_hotdata.tcpv6_offload.secret +#define udp6_ehash_secret net_hotdata.udpv6_protocol.secret +#define udp_ipv6_hash_secret net_hotdata.udpv6_offload.secret + +extern struct net_hotdata net_hotdata; + +#endif /* _NET_HOTDATA_H */ -- cgit v1.3.1