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, 38 insertions, 0 deletions

diff --git a/tools/perf/util/pfm.h b/tools/perf/util/pfm.h
new file mode 100644
index 000000000..fb25c2749
--- /dev/null
+++ b/tools/perf/util/pfm.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Support for libpfm4 event encoding.
+ *
+ * Copyright 2020 Google LLC.
+ */
+#ifndef __PERF_PFM_H
+#define __PERF_PFM_H
+
+#include "print-events.h"
+#include <subcmd/parse-options.h>
+
+#ifdef HAVE_LIBPFM
+int parse_libpfm_events_option(const struct option *opt, const char *str,
+			int unset);
+
+void print_libpfm_events(const struct print_callbacks *print_cb, void *print_state);
+
+#else
+#include <linux/compiler.h>
+
+static inline int parse_libpfm_events_option(
+	const struct option *opt __maybe_unused,
+	const char *str __maybe_unused,
+	int unset __maybe_unused)
+{
+	return 0;
+}
+
+static inline void print_libpfm_events(const struct print_callbacks *print_cb __maybe_unused,
+				       void *print_state __maybe_unused)
+{
+}
+
+#endif
+
+
+#endif /* __PERF_PFM_H */