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, 52 insertions, 0 deletions

diff --git a/arch/mips/loongson64/pm.c b/arch/mips/loongson64/pm.c
new file mode 100644
index 000000000..5f0604af8
--- /dev/null
+++ b/arch/mips/loongson64/pm.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * loongson-specific suspend support
+ *
+ *  Copyright (C) 2009 Lemote Inc.
+ *  Author: Wu Zhangjin <wuzhangjin@gmail.com>
+ */
+#include <linux/suspend.h>
+#include <linux/pm.h>
+
+#include <asm/mipsregs.h>
+
+#include <loongson.h>
+
+asmlinkage void loongson_lefi_sleep(unsigned long sleep_addr);
+
+static int lefi_pm_enter(suspend_state_t state)
+{
+	switch (state) {
+	case PM_SUSPEND_MEM:
+		pm_set_suspend_via_firmware();
+		loongson_lefi_sleep(loongson_sysconf.suspend_addr);
+		pm_set_resume_via_firmware();
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int lefi_pm_valid_state(suspend_state_t state)
+{
+	switch (state) {
+	case PM_SUSPEND_MEM:
+		return !!loongson_sysconf.suspend_addr;
+	default:
+		return 0;
+	}
+}
+
+static const struct platform_suspend_ops lefi_pm_ops = {
+	.valid	= lefi_pm_valid_state,
+	.enter	= lefi_pm_enter,
+};
+
+static int __init loongson_pm_init(void)
+{
+	if (loongson_sysconf.fw_interface == LOONGSON_LEFI)
+		suspend_set_ops(&lefi_pm_ops);
+
+	return 0;
+}
+arch_initcall(loongson_pm_init);