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/befs/btree.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) create mode 100644 fs/befs/btree.h (limited to 'fs/befs/btree.h') diff --git a/fs/befs/btree.h b/fs/befs/btree.h new file mode 100644 index 000000000..a253a6276 --- /dev/null +++ b/fs/befs/btree.h @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * btree.h + * + */ + +int befs_btree_find(struct super_block *sb, const befs_data_stream *ds, + const char *key, befs_off_t *value); + +int befs_btree_read(struct super_block *sb, const befs_data_stream *ds, + loff_t key_no, size_t bufsize, char *keybuf, + size_t *keysize, befs_off_t *value); -- cgit v1.3.1