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, 72 insertions, 0 deletions

diff --git a/include/soc/tegra/pm.h b/include/soc/tegra/pm.h
new file mode 100644
index 000000000..ce4d0b1bd
--- /dev/null
+++ b/include/soc/tegra/pm.h
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2014 NVIDIA Corporation
+ */
+
+#ifndef __SOC_TEGRA_PM_H__
+#define __SOC_TEGRA_PM_H__
+
+#include <linux/errno.h>
+
+enum tegra_suspend_mode {
+	TEGRA_SUSPEND_NONE = 0,
+	TEGRA_SUSPEND_LP2, /* CPU voltage off */
+	TEGRA_SUSPEND_LP1, /* CPU voltage off, DRAM self-refresh */
+	TEGRA_SUSPEND_LP0, /* CPU + core voltage off, DRAM self-refresh */
+	TEGRA_MAX_SUSPEND_MODE,
+	TEGRA_SUSPEND_NOT_READY,
+};
+
+#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_ARM) && defined(CONFIG_ARCH_TEGRA)
+enum tegra_suspend_mode
+tegra_pm_validate_suspend_mode(enum tegra_suspend_mode mode);
+
+/* low-level resume entry point */
+void tegra_resume(void);
+
+int tegra30_pm_secondary_cpu_suspend(unsigned long arg);
+void tegra_pm_clear_cpu_in_lp2(void);
+void tegra_pm_set_cpu_in_lp2(void);
+int tegra_pm_enter_lp2(void);
+int tegra_pm_park_secondary_cpu(unsigned long cpu);
+void tegra_pm_init_suspend(void);
+#else
+static inline enum tegra_suspend_mode
+tegra_pm_validate_suspend_mode(enum tegra_suspend_mode mode)
+{
+	return TEGRA_SUSPEND_NONE;
+}
+
+static inline void tegra_resume(void)
+{
+}
+
+static inline int tegra30_pm_secondary_cpu_suspend(unsigned long arg)
+{
+	return -ENOTSUPP;
+}
+
+static inline void tegra_pm_clear_cpu_in_lp2(void)
+{
+}
+
+static inline void tegra_pm_set_cpu_in_lp2(void)
+{
+}
+
+static inline int tegra_pm_enter_lp2(void)
+{
+	return -ENOTSUPP;
+}
+
+static inline int tegra_pm_park_secondary_cpu(unsigned long cpu)
+{
+	return -ENOTSUPP;
+}
+
+static inline void tegra_pm_init_suspend(void)
+{
+}
+#endif /* CONFIG_PM_SLEEP */
+
+#endif /* __SOC_TEGRA_PM_H__ */