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, 54 insertions, 0 deletions

diff --git a/arch/powerpc/boot/mvme7100.c b/arch/powerpc/boot/mvme7100.c
new file mode 100644
index 000000000..1e218454a
--- /dev/null
+++ b/arch/powerpc/boot/mvme7100.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Motload compatibility for the Emerson/Artesyn MVME7100
+ *
+ * Copyright 2016 Elettra-Sincrotrone Trieste S.C.p.A.
+ *
+ * Author: Alessio Igor Bogani <alessio.bogani@elettra.eu>
+ */
+
+#include "ops.h"
+#include "stdio.h"
+#include "cuboot.h"
+
+#define TARGET_86xx
+#define TARGET_HAS_ETH1
+#define TARGET_HAS_ETH2
+#define TARGET_HAS_ETH3
+#include "ppcboot.h"
+
+static bd_t bd;
+
+BSS_STACK(16384);
+
+static void mvme7100_fixups(void)
+{
+	void *devp;
+	unsigned long busfreq = bd.bi_busfreq * 1000000;
+
+	dt_fixup_cpu_clocks(bd.bi_intfreq * 1000000, busfreq / 4, busfreq);
+
+	devp = finddevice("/soc@f1000000");
+	if (devp)
+		setprop(devp, "bus-frequency", &busfreq, sizeof(busfreq));
+
+	devp = finddevice("/soc/serial@4500");
+	if (devp)
+		setprop(devp, "clock-frequency", &busfreq, sizeof(busfreq));
+
+	dt_fixup_memory(bd.bi_memstart, bd.bi_memsize);
+
+	dt_fixup_mac_address_by_alias("ethernet0", bd.bi_enetaddr);
+	dt_fixup_mac_address_by_alias("ethernet1", bd.bi_enet1addr);
+	dt_fixup_mac_address_by_alias("ethernet2", bd.bi_enet2addr);
+	dt_fixup_mac_address_by_alias("ethernet3", bd.bi_enet3addr);
+}
+
+void platform_init(unsigned long r3, unsigned long r4, unsigned long r5,
+		   unsigned long r6, unsigned long r7)
+{
+	CUBOOT_INIT();
+	fdt_init(_dtb_start);
+	serial_console_init();
+	platform_ops.fixups = mvme7100_fixups;
+}