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, 39 insertions, 0 deletions

diff --git a/drivers/interconnect/qcom/icc-common.c b/drivers/interconnect/qcom/icc-common.c
new file mode 100644
index 000000000..a25564fe1
--- /dev/null
+++ b/drivers/interconnect/qcom/icc-common.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022 Linaro Ltd.
+ */
+
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+
+#include "icc-common.h"
+
+struct icc_node_data *qcom_icc_xlate_extended(const struct of_phandle_args *spec,
+					      void *data)
+{
+	struct icc_node_data *ndata;
+	struct icc_node *node;
+
+	node = of_icc_xlate_onecell(spec, data);
+	if (IS_ERR(node))
+		return ERR_CAST(node);
+
+	ndata = kzalloc_obj(*ndata);
+	if (!ndata)
+		return ERR_PTR(-ENOMEM);
+
+	ndata->node = node;
+
+	if (spec->args_count == 2)
+		ndata->tag = spec->args[1];
+
+	if (spec->args_count > 2)
+		pr_warn("%pOF: Too many arguments, path tag is not parsed\n", spec->np);
+
+	return ndata;
+}
+EXPORT_SYMBOL_GPL(qcom_icc_xlate_extended);
+
+MODULE_DESCRIPTION("Qualcomm interconnect common functions");
+MODULE_LICENSE("GPL");