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, 15 insertions, 0 deletions

diff --git a/drivers/dpll/zl3073x/devlink.h b/drivers/dpll/zl3073x/devlink.h
new file mode 100644
index 000000000..63dfd6fa1
--- /dev/null
+++ b/drivers/dpll/zl3073x/devlink.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _ZL3073X_DEVLINK_H
+#define _ZL3073X_DEVLINK_H
+
+struct zl3073x_dev;
+
+struct zl3073x_dev *zl3073x_devm_alloc(struct device *dev);
+
+int zl3073x_devlink_register(struct zl3073x_dev *zldev);
+
+void zl3073x_devlink_flash_notify(struct zl3073x_dev *zldev, const char *msg,
+				  const char *component, u32 done, u32 total);
+
+#endif /* _ZL3073X_DEVLINK_H */