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/smc.h | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 106 insertions(+) create mode 100644 include/net/smc.h (limited to 'include/net/smc.h') diff --git a/include/net/smc.h b/include/net/smc.h new file mode 100644 index 000000000..a2bc3ab88 --- /dev/null +++ b/include/net/smc.h @@ -0,0 +1,106 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Shared Memory Communications over RDMA (SMC-R) and RoCE + * + * Definitions for the SMC module (socket related) + * + * Copyright IBM Corp. 2016 + * + * Author(s): Ursula Braun + */ +#ifndef _SMC_H +#define _SMC_H + +#include +#include +#include +#include +#include + +struct tcp_sock; +struct inet_request_sock; +struct sock; + +#define SMC_MAX_PNETID_LEN 16 /* Max. length of PNET id */ + +struct smc_hashinfo { + rwlock_t lock; + struct hlist_head ht; +}; + +/* SMCD/ISM device driver interface */ +#define ISM_RESERVED_VLANID 0x1FFF + +struct smcd_gid { + u64 gid; + u64 gid_ext; +}; + +struct smcd_dev { + struct dibs_dev *dibs; + struct list_head list; + spinlock_t lock; + struct list_head vlan; + struct workqueue_struct *event_wq; + u8 pnetid[SMC_MAX_PNETID_LEN]; + bool pnetid_by_user; + struct list_head lgr_list; + spinlock_t lgr_lock; + atomic_t lgr_cnt; + wait_queue_head_t lgrs_deleted; + u8 going_away : 1; + struct smc_connection *conn[]; +}; + +#define SMC_HS_CTRL_NAME_MAX 16 + +enum { + /* ops can be inherit from init_net */ + SMC_HS_CTRL_FLAG_INHERITABLE = 0x1, + + SMC_HS_CTRL_ALL_FLAGS = SMC_HS_CTRL_FLAG_INHERITABLE, +}; + +struct smc_hs_ctrl { + /* private */ + + struct list_head list; + struct module *owner; + + /* public */ + + /* unique name */ + char name[SMC_HS_CTRL_NAME_MAX]; + int flags; + + /* Invoked before computing SMC option for SYN packets. + * We can control whether to set SMC options by returning various value. + * Return 0 to disable SMC, or return any other value to enable it. + */ + int (*syn_option)(struct tcp_sock *tp); + + /* Invoked before Set up SMC options for SYN-ACK packets + * We can control whether to respond SMC options by returning various + * value. Return 0 to disable SMC, or return any other value to enable + * it. + */ + int (*synack_option)(const struct tcp_sock *tp, + struct inet_request_sock *ireq); +}; + +#if IS_ENABLED(CONFIG_SMC_HS_CTRL_BPF) +#define smc_call_hsbpf(init_val, tp, func, ...) ({ \ + typeof(init_val) __ret = (init_val); \ + struct smc_hs_ctrl *ctrl; \ + rcu_read_lock(); \ + ctrl = rcu_dereference(sock_net((struct sock *)(tp))->smc.hs_ctrl); \ + if (ctrl && ctrl->func) \ + __ret = ctrl->func(tp, ##__VA_ARGS__); \ + rcu_read_unlock(); \ + __ret; \ +}) +#else +#define smc_call_hsbpf(init_val, tp, ...) ({ (void)(tp); (init_val); }) +#endif /* CONFIG_SMC_HS_CTRL_BPF */ + +#endif /* _SMC_H */ -- cgit v1.3.1