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, 77 insertions, 0 deletions

diff --git a/net/mac80211/trace.c b/net/mac80211/trace.c
new file mode 100644
index 000000000..837857261
--- /dev/null
+++ b/net/mac80211/trace.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0
+/* bug in tracepoint.h, it should include this */
+#include <linux/module.h>
+
+/* sparse isn't too happy with all macros... */
+#ifndef __CHECKER__
+#include <net/cfg80211.h>
+#include "driver-ops.h"
+#include "debug.h"
+#define CREATE_TRACE_POINTS
+#include "trace.h"
+#include "trace_msg.h"
+
+#ifdef CONFIG_MAC80211_MESSAGE_TRACING
+void __sdata_info(const char *fmt, ...)
+{
+	struct va_format vaf = {
+		.fmt = fmt,
+	};
+	va_list args;
+
+	va_start(args, fmt);
+	vaf.va = &args;
+
+	pr_info("%pV", &vaf);
+	trace_mac80211_info(&vaf);
+	va_end(args);
+}
+
+void __sdata_dbg(bool print, const char *fmt, ...)
+{
+	struct va_format vaf = {
+		.fmt = fmt,
+	};
+	va_list args;
+
+	va_start(args, fmt);
+	vaf.va = &args;
+
+	if (print)
+		pr_debug("%pV", &vaf);
+	trace_mac80211_dbg(&vaf);
+	va_end(args);
+}
+
+void __sdata_err(const char *fmt, ...)
+{
+	struct va_format vaf = {
+		.fmt = fmt,
+	};
+	va_list args;
+
+	va_start(args, fmt);
+	vaf.va = &args;
+
+	pr_err("%pV", &vaf);
+	trace_mac80211_err(&vaf);
+	va_end(args);
+}
+
+void __wiphy_dbg(struct wiphy *wiphy, bool print, const char *fmt, ...)
+{
+	struct va_format vaf = {
+		.fmt = fmt,
+	};
+	va_list args;
+
+	va_start(args, fmt);
+	vaf.va = &args;
+
+	if (print)
+		wiphy_dbg(wiphy, "%pV", &vaf);
+	trace_mac80211_dbg(&vaf);
+	va_end(args);
+}
+#endif
+#endif