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/coda/coda_cache.h | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) create mode 100644 fs/coda/coda_cache.h (limited to 'fs/coda/coda_cache.h') diff --git a/fs/coda/coda_cache.h b/fs/coda/coda_cache.h new file mode 100644 index 000000000..c9f7a77c0 --- /dev/null +++ b/fs/coda/coda_cache.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Coda filesystem -- Linux Minicache + * + * Copyright (C) 1989 - 1997 Carnegie Mellon University + * + * Carnegie Mellon University encourages users of this software to + * contribute improvements to the Coda project. Contact Peter Braam + * + */ + +#ifndef _CFSNC_HEADER_ +#define _CFSNC_HEADER_ + +/* credential cache */ +void coda_cache_enter(struct inode *inode, int mask); +void coda_cache_clear_inode(struct inode *); +void coda_cache_clear_all(struct super_block *sb); +int coda_cache_check(struct inode *inode, int mask); + +/* for downcalls and attributes and lookups */ +void coda_flag_inode_children(struct inode *inode, int flag); + +#endif /* _CFSNC_HEADER_ */ -- cgit v1.3.1