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/numeric.h | 78 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100644 drivers/md/dm-vdo/numeric.h (limited to 'drivers/md/dm-vdo/numeric.h') diff --git a/drivers/md/dm-vdo/numeric.h b/drivers/md/dm-vdo/numeric.h new file mode 100644 index 000000000..f568dc59e --- /dev/null +++ b/drivers/md/dm-vdo/numeric.h @@ -0,0 +1,78 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright 2023 Red Hat + */ + +#ifndef UDS_NUMERIC_H +#define UDS_NUMERIC_H + +#include +#include +#include + +/* + * These utilities encode or decode a number from an offset in a larger data buffer and then + * advance the offset pointer to the next field in the buffer. + */ + +static inline void decode_s64_le(const u8 *buffer, size_t *offset, s64 *decoded) +{ + *decoded = get_unaligned_le64(buffer + *offset); + *offset += sizeof(s64); +} + +static inline void encode_s64_le(u8 *data, size_t *offset, s64 to_encode) +{ + put_unaligned_le64(to_encode, data + *offset); + *offset += sizeof(s64); +} + +static inline void decode_u64_le(const u8 *buffer, size_t *offset, u64 *decoded) +{ + *decoded = get_unaligned_le64(buffer + *offset); + *offset += sizeof(u64); +} + +static inline void encode_u64_le(u8 *data, size_t *offset, u64 to_encode) +{ + put_unaligned_le64(to_encode, data + *offset); + *offset += sizeof(u64); +} + +static inline void decode_s32_le(const u8 *buffer, size_t *offset, s32 *decoded) +{ + *decoded = get_unaligned_le32(buffer + *offset); + *offset += sizeof(s32); +} + +static inline void encode_s32_le(u8 *data, size_t *offset, s32 to_encode) +{ + put_unaligned_le32(to_encode, data + *offset); + *offset += sizeof(s32); +} + +static inline void decode_u32_le(const u8 *buffer, size_t *offset, u32 *decoded) +{ + *decoded = get_unaligned_le32(buffer + *offset); + *offset += sizeof(u32); +} + +static inline void encode_u32_le(u8 *data, size_t *offset, u32 to_encode) +{ + put_unaligned_le32(to_encode, data + *offset); + *offset += sizeof(u32); +} + +static inline void decode_u16_le(const u8 *buffer, size_t *offset, u16 *decoded) +{ + *decoded = get_unaligned_le16(buffer + *offset); + *offset += sizeof(u16); +} + +static inline void encode_u16_le(u8 *data, size_t *offset, u16 to_encode) +{ + put_unaligned_le16(to_encode, data + *offset); + *offset += sizeof(u16); +} + +#endif /* UDS_NUMERIC_H */ -- cgit v1.3.1