From 0bdc4b1ad694293390ffddbb86c0aabc6330e8ba Mon Sep 17 00:00:00 2001
From: Petr Mladek <pmladek@suse.com>
Date: Fri, 28 Nov 2025 14:59:16 +0100
Subject: [PATCH] module: add helper function for reading module_buildid()

[ Upstream commit acfdbb4ab2910ff6f03becb569c23ac7b2223913 ]

Add a helper function for reading the optional "build_id" member of struct
module.  It is going to be used also in ftrace_mod_address_lookup().

Use "#ifdef" instead of "#if IS_ENABLED()" to match the declaration of the
optional field in struct module.

Link: https://lkml.kernel.org/r/20251128135920.217303-4-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Daniel Gomez <da.gomez@samsung.com>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
Cc: Aaron Tomlin <atomlin@atomlin.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkman <daniel@iogearbox.net>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Luis Chamberalin <mcgrof@kernel.org>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: e8a1e7eaa19d ("kallsyms/ftrace: set module buildid in ftrace_mod_address_lookup()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/module.h   | 9 +++++++++
 kernel/module/kallsyms.c | 9 ++-------
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 7886217c9988..1cb6f80e1b48 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -750,6 +750,15 @@ static inline void __module_get(struct module *module)
 	__mod ? __mod->name : "kernel";		\
 })
 
+static inline const unsigned char *module_buildid(struct module *mod)
+{
+#ifdef CONFIG_STACKTRACE_BUILD_ID
+	return mod->build_id;
+#else
+	return NULL;
+#endif
+}
+
 /* Dereference module function descriptor */
 void *dereference_module_function_descriptor(struct module *mod, void *ptr);
 
diff --git a/kernel/module/kallsyms.c b/kernel/module/kallsyms.c
index bf65e0c3c86f..30d0798f114f 100644
--- a/kernel/module/kallsyms.c
+++ b/kernel/module/kallsyms.c
@@ -337,13 +337,8 @@ int module_address_lookup(unsigned long addr,
 	if (mod) {
 		if (modname)
 			*modname = mod->name;
-		if (modbuildid) {
-#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
-			*modbuildid = mod->build_id;
-#else
-			*modbuildid = NULL;
-#endif
-		}
+		if (modbuildid)
+			*modbuildid = module_buildid(mod);
 
 		sym = find_kallsyms_symbol(mod, addr, size, offset);