bpf: mark a NULL kfunc argument precisegrafted

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/arch/mips/cobalt/reset.c b/arch/mips/cobalt/reset.c
new file mode 100644
index 000000000..4eedd481d
--- /dev/null
+++ b/arch/mips/cobalt/reset.c
@@ -0,0 +1,52 @@
+/*
+ * Cobalt Reset operations
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1995, 1996, 1997 by Ralf Baechle
+ * Copyright (C) 2001 by Liam Davies (ldavies@agile.tv)
+ */
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/leds.h>
+
+#include <asm/idle.h>
+#include <asm/processor.h>
+
+#include <cobalt.h>
+
+#define RESET_PORT	((void __iomem *)CKSEG1ADDR(0x1c000000))
+#define RESET		0x0f
+
+DEFINE_LED_TRIGGER(power_off_led_trigger);
+
+static int __init ledtrig_power_off_init(void)
+{
+	led_trigger_register_simple("power-off", &power_off_led_trigger);
+	return 0;
+}
+device_initcall(ledtrig_power_off_init);
+
+void cobalt_machine_halt(void)
+{
+	/*
+	 * turn on power off LED on RaQ
+	 */
+	led_trigger_event(power_off_led_trigger, LED_FULL);
+
+	local_irq_disable();
+	while (1) {
+		if (cpu_wait)
+			cpu_wait();
+	}
+}
+
+void cobalt_machine_restart(char *command)
+{
+	writeb(RESET, RESET_PORT);
+
+	/* we should never get here */
+	cobalt_machine_halt();
+}