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, 32 insertions, 0 deletions

diff --git a/drivers/mfd/simple-mfd-i2c.h b/drivers/mfd/simple-mfd-i2c.h
new file mode 100644
index 000000000..7cb2bdd34
--- /dev/null
+++ b/drivers/mfd/simple-mfd-i2c.h
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Simple MFD - I2C
+ *
+ * Author: Lee Jones <lee.jones@linaro.org>
+ *
+ * This driver creates a single register map with the intention for it to be
+ * shared by all sub-devices.  Children can use their parent's device structure
+ * (dev.parent) in order to reference it.
+ *
+ * This driver creates a single register map with the intention for it to be
+ * shared by all sub-devices.  Children can use their parent's device structure
+ * (dev.parent) in order to reference it.
+ *
+ * Once the register map has been successfully initialised, any sub-devices
+ * represented by child nodes in Device Tree or via the MFD cells in the
+ * associated C file will be subsequently registered.
+ */
+
+#ifndef __MFD_SIMPLE_MFD_I2C_H
+#define __MFD_SIMPLE_MFD_I2C_H
+
+#include <linux/mfd/core.h>
+#include <linux/regmap.h>
+
+struct simple_mfd_data {
+	const struct regmap_config *regmap_config;
+	const struct mfd_cell *mfd_cell;
+	size_t mfd_cell_size;
+};
+
+#endif /* __MFD_SIMPLE_MFD_I2C_H */