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/xfs/scrub/dabtree.h | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 fs/xfs/scrub/dabtree.h (limited to 'fs/xfs/scrub/dabtree.h') diff --git a/fs/xfs/scrub/dabtree.h b/fs/xfs/scrub/dabtree.h new file mode 100644 index 000000000..de291e3b7 --- /dev/null +++ b/fs/xfs/scrub/dabtree.h @@ -0,0 +1,46 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2017-2023 Oracle. All Rights Reserved. + * Author: Darrick J. Wong + */ +#ifndef __XFS_SCRUB_DABTREE_H__ +#define __XFS_SCRUB_DABTREE_H__ + +/* dir/attr btree */ + +struct xchk_da_btree { + struct xfs_da_args dargs; + xfs_dahash_t hashes[XFS_DA_NODE_MAXDEPTH]; + int maxrecs[XFS_DA_NODE_MAXDEPTH]; + struct xfs_da_state *state; + struct xfs_scrub *sc; + void *private; + + /* + * Lowest and highest directory block address in which we expect + * to find dir/attr btree node blocks. For a directory this + * (presumably) means between LEAF_OFFSET and FREE_OFFSET; for + * attributes there is no limit. + */ + xfs_dablk_t lowest; + xfs_dablk_t highest; + + int tree_level; +}; + +typedef int (*xchk_da_btree_rec_fn)(struct xchk_da_btree *ds, int level); + +/* Check for da btree operation errors. */ +bool xchk_da_process_error(struct xchk_da_btree *ds, int level, int *error); + +/* Check for da btree corruption. */ +void xchk_da_set_corrupt(struct xchk_da_btree *ds, int level); +void xchk_da_set_preen(struct xchk_da_btree *ds, int level); + +void xchk_da_set_preen(struct xchk_da_btree *ds, int level); + +int xchk_da_btree_hash(struct xchk_da_btree *ds, int level, __be32 *hashp); +int xchk_da_btree(struct xfs_scrub *sc, int whichfork, + xchk_da_btree_rec_fn scrub_fn, void *private); + +#endif /* __XFS_SCRUB_DABTREE_H__ */ -- cgit v1.3.1