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, 59 insertions, 0 deletions

diff --git a/drivers/iommu/irq_remapping.h b/drivers/iommu/irq_remapping.h
new file mode 100644
index 000000000..0d6f140b5
--- /dev/null
+++ b/drivers/iommu/irq_remapping.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2012 Advanced Micro Devices, Inc.
+ * Author: Joerg Roedel <jroedel@suse.de>
+ *
+ * This header file contains stuff that is shared between different interrupt
+ * remapping drivers but with no need to be visible outside of the IOMMU layer.
+ */
+
+#ifndef __IRQ_REMAPPING_H
+#define __IRQ_REMAPPING_H
+
+#ifdef CONFIG_IRQ_REMAP
+
+struct irq_data;
+struct msi_msg;
+struct irq_domain;
+struct irq_alloc_info;
+
+extern int irq_remap_broken;
+extern int disable_sourceid_checking;
+extern int no_x2apic_optout;
+extern int irq_remapping_enabled;
+
+extern int disable_irq_post;
+
+struct irq_remap_ops {
+	/* The supported capabilities */
+	int capability;
+
+	/* Initializes hardware and makes it ready for remapping interrupts */
+	int  (*prepare)(void);
+
+	/* Enables the remapping hardware */
+	int  (*enable)(void);
+
+	/* Disables the remapping hardware */
+	void (*disable)(void);
+
+	/* Reenables the remapping hardware */
+	int  (*reenable)(int);
+
+	/* Enable fault handling */
+	int  (*enable_faulting)(unsigned int);
+};
+
+extern struct irq_remap_ops intel_irq_remap_ops;
+extern struct irq_remap_ops amd_iommu_irq_ops;
+extern struct irq_remap_ops hyperv_irq_remap_ops;
+
+#else  /* CONFIG_IRQ_REMAP */
+
+#define irq_remapping_enabled 0
+#define irq_remap_broken      0
+#define disable_irq_post      1
+
+#endif /* CONFIG_IRQ_REMAP */
+
+#endif /* __IRQ_REMAPPING_H */