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/ocfs2/dcache.h | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 fs/ocfs2/dcache.h (limited to 'fs/ocfs2/dcache.h') diff --git a/fs/ocfs2/dcache.h b/fs/ocfs2/dcache.h new file mode 100644 index 000000000..7f246c569 --- /dev/null +++ b/fs/ocfs2/dcache.h @@ -0,0 +1,43 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * dcache.h + * + * Function prototypes + * + * Copyright (C) 2002, 2004 Oracle. All rights reserved. + */ + +#ifndef OCFS2_DCACHE_H +#define OCFS2_DCACHE_H + +extern const struct dentry_operations ocfs2_dentry_ops; + +struct ocfs2_dentry_lock { + unsigned int dl_count; + u64 dl_parent_blkno; + + /* + * The ocfs2_dentry_lock keeps an inode reference until + * dl_lockres has been destroyed. This is usually done in + * ->d_iput() anyway, so there should be minimal impact. + */ + struct inode *dl_inode; + struct ocfs2_lock_res dl_lockres; +}; + +int ocfs2_dentry_attach_lock(struct dentry *dentry, struct inode *inode, + u64 parent_blkno); + +void ocfs2_dentry_lock_put(struct ocfs2_super *osb, + struct ocfs2_dentry_lock *dl); + +struct dentry *ocfs2_find_local_alias(struct inode *inode, u64 parent_blkno, + int skip_unhashed); + +void ocfs2_dentry_move(struct dentry *dentry, struct dentry *target, + struct inode *old_dir, struct inode *new_dir); + +extern spinlock_t dentry_attach_lock; +void ocfs2_dentry_attach_gen(struct dentry *dentry); + +#endif /* OCFS2_DCACHE_H */ -- cgit v1.3.1