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, 36 insertions, 0 deletions

diff --git a/net/batman-adv/log.c b/net/batman-adv/log.c
new file mode 100644
index 000000000..c19d07eeb
--- /dev/null
+++ b/net/batman-adv/log.c
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) B.A.T.M.A.N. contributors:
+ *
+ * Marek Lindner
+ */
+
+#include "log.h"
+#include "main.h"
+
+#include <linux/stdarg.h>
+
+#include "trace.h"
+
+/**
+ * batadv_debug_log() - Add debug log entry
+ * @bat_priv: the bat priv with all the mesh interface information
+ * @fmt: format string
+ *
+ * Return: 0 on success or negative error number in case of failure
+ */
+int batadv_debug_log(struct batadv_priv *bat_priv, const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	trace_batadv_dbg(bat_priv, &vaf);
+
+	va_end(args);
+
+	return 0;
+}