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, 27 insertions, 0 deletions

diff --git a/include/net/firewire.h b/include/net/firewire.h
new file mode 100644
index 000000000..8fbff8d77
--- /dev/null
+++ b/include/net/firewire.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _NET_FIREWIRE_H
+#define _NET_FIREWIRE_H
+
+#include <linux/types.h>
+
+/* Pseudo L2 address */
+#define FWNET_ALEN	16
+union fwnet_hwaddr {
+	u8 u[FWNET_ALEN];
+	/* "Hardware address" defined in RFC2734/RF3146 */
+	struct {
+		__be64 uniq_id;		/* EUI-64			*/
+		u8 max_rec;		/* max packet size		*/
+		u8 sspd;		/* max speed			*/
+		u8 fifo[6];		/* FIFO addr			*/
+	} __packed uc;
+};
+
+/* Pseudo L2 Header */
+#define FWNET_HLEN	18
+struct fwnet_header {
+	u8 h_dest[FWNET_ALEN];	/* destination address */
+	__be16 h_proto;		/* packet type ID field */
+} __packed;
+
+#endif