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/rdma/restrack.h | 183 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 183 insertions(+) create mode 100644 include/rdma/restrack.h (limited to 'include/rdma/restrack.h') diff --git a/include/rdma/restrack.h b/include/rdma/restrack.h new file mode 100644 index 000000000..451f99e37 --- /dev/null +++ b/include/rdma/restrack.h @@ -0,0 +1,183 @@ +/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */ +/* + * Copyright (c) 2017-2018 Mellanox Technologies. All rights reserved. + */ + +#ifndef _RDMA_RESTRACK_H_ +#define _RDMA_RESTRACK_H_ + +#include +#include +#include +#include +#include +#include +#include + +/* Mark entry as containing driver specific details, it is used to provide QP subtype for now */ +#define RESTRACK_DD XA_MARK_1 + +struct ib_device; +struct sk_buff; + +/** + * enum rdma_restrack_type - HW objects to track + */ +enum rdma_restrack_type { + /** + * @RDMA_RESTRACK_PD: Protection domain (PD) + */ + RDMA_RESTRACK_PD, + /** + * @RDMA_RESTRACK_CQ: Completion queue (CQ) + */ + RDMA_RESTRACK_CQ, + /** + * @RDMA_RESTRACK_QP: Queue pair (QP) + */ + RDMA_RESTRACK_QP, + /** + * @RDMA_RESTRACK_CM_ID: Connection Manager ID (CM_ID) + */ + RDMA_RESTRACK_CM_ID, + /** + * @RDMA_RESTRACK_MR: Memory Region (MR) + */ + RDMA_RESTRACK_MR, + /** + * @RDMA_RESTRACK_CTX: Verbs contexts (CTX) + */ + RDMA_RESTRACK_CTX, + /** + * @RDMA_RESTRACK_COUNTER: Statistic Counter + */ + RDMA_RESTRACK_COUNTER, + /** + * @RDMA_RESTRACK_SRQ: Shared receive queue (SRQ) + */ + RDMA_RESTRACK_SRQ, + /** + * @RDMA_RESTRACK_DMAH: DMA handle + */ + RDMA_RESTRACK_DMAH, + /** + * @RDMA_RESTRACK_MAX: Last entry, used for array dclarations + */ + RDMA_RESTRACK_MAX +}; + +/** + * struct rdma_restrack_entry - metadata per-entry + */ +struct rdma_restrack_entry { + /** + * @valid: validity indicator + * + * The entries are filled during rdma_restrack_add, + * can be attempted to be free during rdma_restrack_del. + * + * As an example for that, see mlx5 QPs with type MLX5_IB_QPT_HW_GSI + */ + bool valid; + /** + * @no_track: don't add this entry to restrack DB + * + * This field is used to mark an entry that doesn't need to be added to + * internal restrack DB and presented later to the users at the nldev + * query stage. + */ + u8 no_track : 1; + /** + * @kref: Protect destroy of the resource + */ + struct kref kref; + /** + * @comp: Signal that all consumers of resource are completed their work + */ + struct completion comp; + /** + * @task: owner of resource tracking entity + * + * There are two types of entities: created by user and created + * by kernel. + * + * This is relevant for the entities created by users. + * For the entities created by kernel, this pointer will be NULL. + */ + struct task_struct *task; + /** + * @kern_name: name of owner for the kernel created entities. + */ + const char *kern_name; + /** + * @type: various objects in restrack database + */ + enum rdma_restrack_type type; + /** + * @user: user resource + */ + bool user; + /** + * @id: ID to expose to users + */ + u32 id; +}; + +int rdma_restrack_count(struct ib_device *dev, enum rdma_restrack_type type, + bool show_details); +/** + * rdma_is_kernel_res() - check the owner of resource + * @res: resource entry + */ +static inline bool rdma_is_kernel_res(const struct rdma_restrack_entry *res) +{ + return !res->user; +} + +/** + * rdma_restrack_get() - grab to protect resource from release + * @res: resource entry + */ +int __must_check rdma_restrack_get(struct rdma_restrack_entry *res); + +/** + * rdma_restrack_put() - release resource + * @res: resource entry + */ +int rdma_restrack_put(struct rdma_restrack_entry *res); + +/* + * Helper functions for rdma drivers when filling out + * nldev driver attributes. + */ +int rdma_nl_put_driver_u32(struct sk_buff *msg, const char *name, u32 value); +int rdma_nl_put_driver_u32_hex(struct sk_buff *msg, const char *name, + u32 value); +int rdma_nl_put_driver_u64(struct sk_buff *msg, const char *name, u64 value); +int rdma_nl_put_driver_u64_hex(struct sk_buff *msg, const char *name, + u64 value); +int rdma_nl_put_driver_string(struct sk_buff *msg, const char *name, + const char *str); +int rdma_nl_stat_hwcounter_entry(struct sk_buff *msg, const char *name, + u64 value); + +struct rdma_restrack_entry *rdma_restrack_get_byid(struct ib_device *dev, + enum rdma_restrack_type type, + u32 id); + +/** + * rdma_restrack_no_track() - don't add resource to the DB + * @res: resource entry + * + * Every user of this API should be cross examined. + * Probably you don't need to use this function. + */ +static inline void rdma_restrack_no_track(struct rdma_restrack_entry *res) +{ + res->no_track = true; +} +static inline bool rdma_restrack_is_tracked(struct rdma_restrack_entry *res) +{ + return !res->no_track; +} +#endif /* _RDMA_RESTRACK_H_ */ -- cgit v1.3.1