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 --- drivers/md/dm-vdo/int-map.h | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 drivers/md/dm-vdo/int-map.h (limited to 'drivers/md/dm-vdo/int-map.h') diff --git a/drivers/md/dm-vdo/int-map.h b/drivers/md/dm-vdo/int-map.h new file mode 100644 index 000000000..1858ad799 --- /dev/null +++ b/drivers/md/dm-vdo/int-map.h @@ -0,0 +1,39 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright 2023 Red Hat + */ + +#ifndef VDO_INT_MAP_H +#define VDO_INT_MAP_H + +#include +#include + +/** + * DOC: int_map + * + * An int_map associates pointers (void *) with integer keys (u64). NULL pointer values are + * not supported. + * + * The map is implemented as hash table, which should provide constant-time insert, query, and + * remove operations, although the insert may occasionally grow the table, which is linear in the + * number of entries in the map. The table will grow as needed to hold new entries, but will not + * shrink as entries are removed. + */ + +struct int_map; + +int __must_check vdo_int_map_create(size_t initial_capacity, struct int_map **map_ptr); + +void vdo_int_map_free(struct int_map *map); + +size_t vdo_int_map_size(const struct int_map *map); + +void *vdo_int_map_get(struct int_map *map, u64 key); + +int __must_check vdo_int_map_put(struct int_map *map, u64 key, void *new_value, + bool update, void **old_value_ptr); + +void *vdo_int_map_remove(struct int_map *map, u64 key); + +#endif /* VDO_INT_MAP_H */ -- cgit v1.3.1