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, 29 insertions, 0 deletions

diff --git a/drivers/crypto/caam/debugfs.h b/drivers/crypto/caam/debugfs.h
new file mode 100644
index 000000000..ef238c71f
--- /dev/null
+++ b/drivers/crypto/caam/debugfs.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause) */
+/* Copyright 2019, 2023 NXP */
+
+#ifndef CAAM_DEBUGFS_H
+#define CAAM_DEBUGFS_H
+
+struct dentry;
+struct caam_drv_private;
+struct caam_perfmon;
+
+#ifdef CONFIG_DEBUG_FS
+void caam_debugfs_init(struct caam_drv_private *ctrlpriv,
+		       struct caam_perfmon __force *perfmon, struct dentry *root);
+#else
+static inline void caam_debugfs_init(struct caam_drv_private *ctrlpriv,
+				     struct caam_perfmon __force *perfmon,
+				     struct dentry *root)
+{}
+#endif
+
+#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_CRYPTO_DEV_FSL_CAAM_CRYPTO_API_QI)
+void caam_debugfs_qi_congested(void);
+void caam_debugfs_qi_init(struct caam_drv_private *ctrlpriv);
+#else
+static inline void caam_debugfs_qi_congested(void) {}
+static inline void caam_debugfs_qi_init(struct caam_drv_private *ctrlpriv) {}
+#endif
+
+#endif /* CAAM_DEBUGFS_H */