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, 128 insertions, 0 deletions

diff --git a/arch/mips/ath25/devices.c b/arch/mips/ath25/devices.c
new file mode 100644
index 000000000..301a90282
--- /dev/null
+++ b/arch/mips/ath25/devices.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/serial_8250.h>
+#include <linux/platform_device.h>
+#include <asm/bootinfo.h>
+
+#include <ath25_platform.h>
+#include "devices.h"
+#include "ar5312.h"
+#include "ar2315.h"
+
+struct ar231x_board_config ath25_board;
+enum ath25_soc_type ath25_soc = ATH25_SOC_UNKNOWN;
+
+static struct resource ath25_wmac0_res[] = {
+	{
+		.name = "wmac0_membase",
+		.flags = IORESOURCE_MEM,
+	},
+	{
+		.name = "wmac0_irq",
+		.flags = IORESOURCE_IRQ,
+	}
+};
+
+static struct resource ath25_wmac1_res[] = {
+	{
+		.name = "wmac1_membase",
+		.flags = IORESOURCE_MEM,
+	},
+	{
+		.name = "wmac1_irq",
+		.flags = IORESOURCE_IRQ,
+	}
+};
+
+static struct platform_device ath25_wmac[] = {
+	{
+		.id = 0,
+		.name = "ar231x-wmac",
+		.resource = ath25_wmac0_res,
+		.num_resources = ARRAY_SIZE(ath25_wmac0_res),
+		.dev.platform_data = &ath25_board,
+	},
+	{
+		.id = 1,
+		.name = "ar231x-wmac",
+		.resource = ath25_wmac1_res,
+		.num_resources = ARRAY_SIZE(ath25_wmac1_res),
+		.dev.platform_data = &ath25_board,
+	},
+};
+
+static const char * const soc_type_strings[] = {
+	[ATH25_SOC_AR5312] = "Atheros AR5312",
+	[ATH25_SOC_AR2312] = "Atheros AR2312",
+	[ATH25_SOC_AR2313] = "Atheros AR2313",
+	[ATH25_SOC_AR2315] = "Atheros AR2315",
+	[ATH25_SOC_AR2316] = "Atheros AR2316",
+	[ATH25_SOC_AR2317] = "Atheros AR2317",
+	[ATH25_SOC_AR2318] = "Atheros AR2318",
+	[ATH25_SOC_UNKNOWN] = "Atheros (unknown)",
+};
+
+const char *get_system_type(void)
+{
+	if ((ath25_soc >= ARRAY_SIZE(soc_type_strings)) ||
+	    !soc_type_strings[ath25_soc])
+		return soc_type_strings[ATH25_SOC_UNKNOWN];
+	return soc_type_strings[ath25_soc];
+}
+
+void __init ath25_serial_setup(u32 mapbase, int irq, unsigned int uartclk)
+{
+#ifdef CONFIG_SERIAL_8250_CONSOLE
+	struct uart_port s;
+
+	memset(&s, 0, sizeof(s));
+
+	s.flags = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST | UPF_IOREMAP;
+	s.iotype = UPIO_MEM32;
+	s.irq = irq;
+	s.regshift = 2;
+	s.mapbase = mapbase;
+	s.uartclk = uartclk;
+
+	early_serial_setup(&s);
+#endif /* CONFIG_SERIAL_8250_CONSOLE */
+}
+
+int __init ath25_add_wmac(int nr, u32 base, int irq)
+{
+	struct resource *res;
+
+	ath25_wmac[nr].dev.platform_data = &ath25_board;
+	res = &ath25_wmac[nr].resource[0];
+	res->start = base;
+	res->end = base + 0x10000 - 1;
+	res++;
+	res->start = irq;
+	res->end = irq;
+	return platform_device_register(&ath25_wmac[nr]);
+}
+
+static int __init ath25_register_devices(void)
+{
+	if (is_ar5312())
+		ar5312_init_devices();
+	else
+		ar2315_init_devices();
+
+	return 0;
+}
+
+device_initcall(ath25_register_devices);
+
+static int __init ath25_arch_init(void)
+{
+	if (is_ar5312())
+		ar5312_arch_init();
+	else
+		ar2315_arch_init();
+
+	return 0;
+}
+
+arch_initcall(ath25_arch_init);