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 --- fs/iomap/internal.h | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 fs/iomap/internal.h (limited to 'fs/iomap/internal.h') diff --git a/fs/iomap/internal.h b/fs/iomap/internal.h new file mode 100644 index 000000000..74e898b19 --- /dev/null +++ b/fs/iomap/internal.h @@ -0,0 +1,35 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _IOMAP_INTERNAL_H +#define _IOMAP_INTERNAL_H 1 + +#define IOEND_BATCH_SIZE 4096 + +/* + * Normally we can build bios as big as the data structure supports. + * + * But for integrity protected I/O we need to respect the maximum size of the + * single contiguous allocation for the integrity buffer. + */ +static inline size_t iomap_max_bio_size(const struct iomap *iomap) +{ + if (iomap->flags & IOMAP_F_INTEGRITY) + return max_integrity_io_size(bdev_limits(iomap->bdev)); + return BIO_MAX_SIZE; +} + +u32 iomap_finish_ioend_buffered_read(struct iomap_ioend *ioend); +u32 iomap_finish_ioend_direct(struct iomap_ioend *ioend); + +#ifdef CONFIG_BLOCK +int iomap_bio_read_folio_range_sync(const struct iomap_iter *iter, + struct folio *folio, loff_t pos, size_t len); +#else +static inline int iomap_bio_read_folio_range_sync(const struct iomap_iter *iter, + struct folio *folio, loff_t pos, size_t len) +{ + WARN_ON_ONCE(1); + return -EIO; +} +#endif /* CONFIG_BLOCK */ + +#endif /* _IOMAP_INTERNAL_H */ -- cgit v1.3.1