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/gen_stats.h | 84 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 include/net/gen_stats.h (limited to 'include/net/gen_stats.h') diff --git a/include/net/gen_stats.h b/include/net/gen_stats.h new file mode 100644 index 000000000..856b5e90f --- /dev/null +++ b/include/net/gen_stats.h @@ -0,0 +1,84 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __NET_GEN_STATS_H +#define __NET_GEN_STATS_H + +#include +#include +#include +#include + +/* Throughput stats. + * Must be initialized beforehand with gnet_stats_basic_sync_init(). + * + * If no reads can ever occur parallel to writes (e.g. stack-allocated + * bstats), then the internal stat values can be written to and read + * from directly. Otherwise, use _bstats_set/update() for writes and + * gnet_stats_add_basic() for reads. + */ +struct gnet_stats_basic_sync { + u64_stats_t bytes; + u64_stats_t packets; + struct u64_stats_sync syncp; +} __aligned(2 * sizeof(u64)); + +struct net_rate_estimator; + +struct gnet_dump { + spinlock_t * lock; + struct sk_buff * skb; + struct nlattr * tail; + + /* Backward compatibility */ + int compat_tc_stats; + int compat_xstats; + int padattr; + void * xstats; + int xstats_len; + struct tc_stats tc_stats; +}; + +void gnet_stats_basic_sync_init(struct gnet_stats_basic_sync *b); +int gnet_stats_start_copy(struct sk_buff *skb, int type, spinlock_t *lock, + struct gnet_dump *d, int padattr); + +int gnet_stats_start_copy_compat(struct sk_buff *skb, int type, + int tc_stats_type, int xstats_type, + spinlock_t *lock, struct gnet_dump *d, + int padattr); + +int gnet_stats_copy_basic(struct gnet_dump *d, + const struct gnet_stats_basic_sync __percpu *cpu, + const struct gnet_stats_basic_sync *b, bool running); +void gnet_stats_add_basic(struct gnet_stats_basic_sync *bstats, + const struct gnet_stats_basic_sync __percpu *cpu, + const struct gnet_stats_basic_sync *b, bool running); +int gnet_stats_copy_basic_hw(struct gnet_dump *d, + const struct gnet_stats_basic_sync __percpu *cpu, + const struct gnet_stats_basic_sync *b, bool running); +int gnet_stats_copy_rate_est(struct gnet_dump *d, + struct net_rate_estimator __rcu **ptr); +int gnet_stats_copy_queue(struct gnet_dump *d, + const struct gnet_stats_queue __percpu *cpu_q, + const struct gnet_stats_queue *q, __u32 qlen); +void gnet_stats_add_queue(struct gnet_stats_queue *qstats, + const struct gnet_stats_queue __percpu *cpu_q, + const struct gnet_stats_queue *q); +int gnet_stats_copy_app(struct gnet_dump *d, void *st, int len); + +int gnet_stats_finish_copy(struct gnet_dump *d); + +int gen_new_estimator(struct gnet_stats_basic_sync *bstats, + struct gnet_stats_basic_sync __percpu *cpu_bstats, + struct net_rate_estimator __rcu **rate_est, + spinlock_t *lock, + bool running, struct nlattr *opt); +void gen_kill_estimator(struct net_rate_estimator __rcu **ptr); +int gen_replace_estimator(struct gnet_stats_basic_sync *bstats, + struct gnet_stats_basic_sync __percpu *cpu_bstats, + struct net_rate_estimator __rcu **ptr, + spinlock_t *lock, + bool running, struct nlattr *opt); +bool gen_estimator_active(struct net_rate_estimator __rcu **ptr); +bool gen_estimator_read(struct net_rate_estimator __rcu **ptr, + struct gnet_stats_rate_est64 *sample); +#endif -- cgit v1.3.1