selftests/bpf: Check that JMP32 pointer vs zero jumps are not predictedgrafted

Add jmp32_ptr_vs_zero_jne: the fall-through of the 32-bit compare, which
the verifier used to skip, contains an out of bounds map value access,
hence w/o the previous patch the program is accepted. See previous patch
for detailed description.

Reported-by: Nicholas Carlini <npc@anthropic.com>
Suggested-by: Nicholas Carlini <npc@anthropic.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20260904083325.2083493-6-eddyz87@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 87 insertions, 0 deletions

diff --git a/tools/include/nolibc/err.h b/tools/include/nolibc/err.h
new file mode 100644
index 000000000..e22ae87a7
--- /dev/null
+++ b/tools/include/nolibc/err.h
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * formatted error message for NOLIBC
+ * Copyright (C) 2026 Thomas Weißschuh <linux@weissschuh.net>
+ */
+
+/* make sure to include all global symbols */
+#include "nolibc.h"
+
+#ifndef _NOLIBC_ERR_H
+#define _NOLIBC_ERR_H
+
+#include "errno.h"
+#include "stdarg.h"
+#include "sys.h"
+
+static __attribute__((unused))
+void vwarn(const char *fmt, va_list args)
+{
+	fprintf(stderr, "%s: ", program_invocation_short_name);
+	vfprintf(stderr, fmt, args);
+	fprintf(stderr, ": %m\n");
+}
+
+static __attribute__((unused))
+void vwarnx(const char *fmt, va_list args)
+{
+	fprintf(stderr, "%s: ", program_invocation_short_name);
+	vfprintf(stderr, fmt, args);
+	fprintf(stderr, "\n");
+}
+
+static __attribute__((unused))
+void warn(const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	vwarn(fmt, args);
+	va_end(args);
+}
+
+static __attribute__((unused))
+void warnx(const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	vwarnx(fmt, args);
+	va_end(args);
+}
+
+static __attribute__((noreturn, unused))
+void verr(int eval, const char *fmt, va_list args)
+{
+	vwarn(fmt, args);
+	exit(eval);
+}
+
+static __attribute__((noreturn, unused))
+void verrx(int eval, const char *fmt, va_list args)
+{
+	warnx(fmt, args);
+	exit(eval);
+}
+
+static __attribute__((noreturn, unused))
+void err(int eval, const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	verr(eval, fmt, args);
+	va_end(args);
+}
+
+static __attribute__((noreturn, unused))
+void errx(int eval, const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	verrx(eval, fmt, args);
+	va_end(args);
+}
+
+#endif /* _NOLIBC_ERR_H */