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, 78 insertions, 0 deletions

diff --git a/fs/udf/udfend.h b/fs/udf/udfend.h
new file mode 100644
index 000000000..a4363ac2c
--- /dev/null
+++ b/fs/udf/udfend.h
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UDF_ENDIAN_H
+#define __UDF_ENDIAN_H
+
+#include <asm/byteorder.h>
+#include <linux/string.h>
+
+static inline struct kernel_lb_addr lelb_to_cpu(struct lb_addr in)
+{
+	struct kernel_lb_addr out;
+
+	out.logicalBlockNum = le32_to_cpu(in.logicalBlockNum);
+	out.partitionReferenceNum = le16_to_cpu(in.partitionReferenceNum);
+
+	return out;
+}
+
+static inline struct lb_addr cpu_to_lelb(struct kernel_lb_addr in)
+{
+	struct lb_addr out;
+
+	out.logicalBlockNum = cpu_to_le32(in.logicalBlockNum);
+	out.partitionReferenceNum = cpu_to_le16(in.partitionReferenceNum);
+
+	return out;
+}
+
+static inline struct short_ad lesa_to_cpu(struct short_ad in)
+{
+	struct short_ad out;
+
+	out.extLength = le32_to_cpu(in.extLength);
+	out.extPosition = le32_to_cpu(in.extPosition);
+
+	return out;
+}
+
+static inline struct short_ad cpu_to_lesa(struct short_ad in)
+{
+	struct short_ad out;
+
+	out.extLength = cpu_to_le32(in.extLength);
+	out.extPosition = cpu_to_le32(in.extPosition);
+
+	return out;
+}
+
+static inline struct kernel_long_ad lela_to_cpu(struct long_ad in)
+{
+	struct kernel_long_ad out;
+
+	out.extLength = le32_to_cpu(in.extLength);
+	out.extLocation = lelb_to_cpu(in.extLocation);
+
+	return out;
+}
+
+static inline struct long_ad cpu_to_lela(struct kernel_long_ad in)
+{
+	struct long_ad out;
+
+	out.extLength = cpu_to_le32(in.extLength);
+	out.extLocation = cpu_to_lelb(in.extLocation);
+
+	return out;
+}
+
+static inline struct kernel_extent_ad leea_to_cpu(struct extent_ad in)
+{
+	struct kernel_extent_ad out;
+
+	out.extLength = le32_to_cpu(in.extLength);
+	out.extLocation = le32_to_cpu(in.extLocation);
+
+	return out;
+}
+
+#endif /* __UDF_ENDIAN_H */