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, 40 insertions, 0 deletions

diff --git a/drivers/leds/trigger/ledtrig-disk.c b/drivers/leds/trigger/ledtrig-disk.c
new file mode 100644
index 000000000..e9b87ee94
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-disk.c
@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * LED Disk Activity Trigger
+ *
+ * Copyright 2006 Openedhand Ltd.
+ *
+ * Author: Richard Purdie <rpurdie@openedhand.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/leds.h>
+
+#define BLINK_DELAY 30
+
+DEFINE_LED_TRIGGER(ledtrig_disk);
+DEFINE_LED_TRIGGER(ledtrig_disk_read);
+DEFINE_LED_TRIGGER(ledtrig_disk_write);
+
+void ledtrig_disk_activity(bool write)
+{
+	led_trigger_blink_oneshot(ledtrig_disk, BLINK_DELAY, BLINK_DELAY, 0);
+	if (write)
+		led_trigger_blink_oneshot(ledtrig_disk_write,
+					  BLINK_DELAY, BLINK_DELAY, 0);
+	else
+		led_trigger_blink_oneshot(ledtrig_disk_read,
+					  BLINK_DELAY, BLINK_DELAY, 0);
+}
+EXPORT_SYMBOL(ledtrig_disk_activity);
+
+static int __init ledtrig_disk_init(void)
+{
+	led_trigger_register_simple("disk-activity", &ledtrig_disk);
+	led_trigger_register_simple("disk-read", &ledtrig_disk_read);
+	led_trigger_register_simple("disk-write", &ledtrig_disk_write);
+
+	return 0;
+}
+device_initcall(ledtrig_disk_init);