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, 36 insertions, 0 deletions

diff --git a/fs/ntfs/collate.h b/fs/ntfs/collate.h
new file mode 100644
index 000000000..8ad1f04be
--- /dev/null
+++ b/fs/ntfs/collate.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Defines for NTFS kernel collation handling.
+ *
+ * Copyright (c) 2004 Anton Altaparmakov
+ *
+ * Part of this file is based on code from the NTFS-3G.
+ * and is copyrighted by the respective authors below:
+ * Copyright (c) 2004 Anton Altaparmakov
+ * Copyright (c) 2005 Yura Pakhuchiy
+ */
+
+#ifndef _LINUX_NTFS_COLLATE_H
+#define _LINUX_NTFS_COLLATE_H
+
+#include "volume.h"
+
+static inline bool ntfs_is_collation_rule_supported(__le32 cr)
+{
+	int i;
+
+	if (unlikely(cr != COLLATION_BINARY && cr != COLLATION_NTOFS_ULONG &&
+		     cr != COLLATION_FILE_NAME) && cr != COLLATION_NTOFS_ULONGS)
+		return false;
+	i = le32_to_cpu(cr);
+	if (likely(((i >= 0) && (i <= 0x02)) ||
+			((i >= 0x10) && (i <= 0x13))))
+		return true;
+	return false;
+}
+
+int ntfs_collate(struct ntfs_volume *vol, __le32 cr,
+		const void *data1, const u32 data1_len,
+		const void *data2, const u32 data2_len);
+
+#endif /* _LINUX_NTFS_COLLATE_H */