selftests/bpf: Reject graph kptr use after RCU unlockgrafted

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 <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 88 insertions, 0 deletions

diff --git a/fs/ocfs2/xattr.h b/fs/ocfs2/xattr.h
new file mode 100644
index 000000000..65e9aa743
--- /dev/null
+++ b/fs/ocfs2/xattr.h
@@ -0,0 +1,88 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * xattr.h
+ *
+ * Copyright (C) 2004, 2008 Oracle.  All rights reserved.
+ */
+
+#ifndef OCFS2_XATTR_H
+#define OCFS2_XATTR_H
+
+#include <linux/init.h>
+#include <linux/xattr.h>
+
+enum ocfs2_xattr_type {
+	OCFS2_XATTR_INDEX_USER = 1,
+	OCFS2_XATTR_INDEX_POSIX_ACL_ACCESS,
+	OCFS2_XATTR_INDEX_POSIX_ACL_DEFAULT,
+	OCFS2_XATTR_INDEX_TRUSTED,
+	OCFS2_XATTR_INDEX_SECURITY,
+	OCFS2_XATTR_MAX
+};
+
+struct ocfs2_security_xattr_info {
+	int enable;
+	const char *name;
+	void *value;
+	size_t value_len;
+};
+
+extern const struct xattr_handler ocfs2_xattr_user_handler;
+extern const struct xattr_handler ocfs2_xattr_trusted_handler;
+extern const struct xattr_handler ocfs2_xattr_security_handler;
+extern const struct xattr_handler * const ocfs2_xattr_handlers[];
+
+ssize_t ocfs2_listxattr(struct dentry *, char *, size_t);
+int ocfs2_xattr_get_nolock(struct inode *, struct buffer_head *, int,
+			   const char *, void *, size_t);
+int ocfs2_xattr_set(struct inode *, int, const char *, const void *,
+		    size_t, int);
+int ocfs2_xattr_set_handle(handle_t *, struct inode *, struct buffer_head *,
+			   int, const char *, const void *, size_t, int,
+			   struct ocfs2_alloc_context *,
+			   struct ocfs2_alloc_context *);
+int ocfs2_has_inline_xattr_value_outside(struct inode *inode,
+					 struct ocfs2_dinode *di);
+int ocfs2_xattr_remove(struct inode *, struct buffer_head *);
+int ocfs2_init_security_get(struct inode *, struct inode *,
+			    const struct qstr *,
+			    struct ocfs2_security_xattr_info *);
+int ocfs2_init_security_set(handle_t *, struct inode *,
+			    struct buffer_head *,
+			    struct ocfs2_security_xattr_info *,
+			    struct ocfs2_alloc_context *,
+			    struct ocfs2_alloc_context *);
+int ocfs2_calc_security_init(struct inode *,
+			     struct ocfs2_security_xattr_info *,
+			     int *, int *, struct ocfs2_alloc_context **);
+int ocfs2_calc_xattr_init(struct inode *, struct buffer_head *,
+			  umode_t, struct ocfs2_security_xattr_info *,
+			  int *, int *, int *);
+
+/*
+ * xattrs can live inside an inode, as part of an external xattr block,
+ * or inside an xattr bucket, which is the leaf of a tree rooted in an
+ * xattr block.  Some of the xattr calls, especially the value setting
+ * functions, want to treat each of these locations as equal.  Let's wrap
+ * them in a structure that we can pass around instead of raw buffer_heads.
+ */
+struct ocfs2_xattr_value_buf {
+	struct buffer_head		*vb_bh;
+	ocfs2_journal_access_func	vb_access;
+	struct ocfs2_xattr_value_root	*vb_xv;
+};
+
+int ocfs2_xattr_attach_refcount_tree(struct inode *inode,
+				     struct buffer_head *fe_bh,
+				     struct ocfs2_caching_info *ref_ci,
+				     struct buffer_head *ref_root_bh,
+				     struct ocfs2_cached_dealloc_ctxt *dealloc);
+int ocfs2_reflink_xattrs(struct inode *old_inode,
+			 struct buffer_head *old_bh,
+			 struct inode *new_inode,
+			 struct buffer_head *new_bh,
+			 bool preserve_security);
+int ocfs2_init_security_and_acl(struct inode *dir,
+				struct inode *inode,
+				const struct qstr *qstr);
+#endif /* OCFS2_XATTR_H */