kallsyms/ftrace: set module buildid in ftrace_mod_address_lookup()

[ Upstream commit e8a1e7e ]

__sprint_symbol() might access an invalid pointer when
kallsyms_lookup_buildid() returns a symbol found by
ftrace_mod_address_lookup().

The ftrace lookup function must set both @modname and @modbuildid the same
way as module_address_lookup().

Link: https://lkml.kernel.org/r/20251128135920.217303-7-pmladek@suse.com
Fixes: 9294523 ("module: add printk formats to add module build ID to stacktraces")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Aaron Tomlin <atomlin@atomlin.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkman <daniel@iogearbox.net>
Cc: Daniel Gomez <da.gomez@samsung.com>
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: Petr Pavlu <petr.pavlu@suse.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: pmladek

include/linux/ftrace.h

@@ -89,11 +89,13 @@ struct ftrace_direct_func;
 	defined(CONFIG_DYNAMIC_FTRACE)
 const char *
 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
-		   unsigned long *off, char **modname, char *sym);
+			  unsigned long *off, char **modname,
+			  const unsigned char **modbuildid, char *sym);
 #else
 static inline const char *
 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
-		   unsigned long *off, char **modname, char *sym)
+			  unsigned long *off, char **modname,
+			  const unsigned char **modbuildid, char *sym)
 {
 	return NULL;
 }

kernel/kallsyms.c

@@ -431,8 +431,8 @@ static const char *kallsyms_lookup_buildid(unsigned long addr,
 					 offset, modname, namebuf);
 
 	if (!ret)
-		ret = ftrace_mod_address_lookup(addr, symbolsize,
-						offset, modname, namebuf);
+		ret = ftrace_mod_address_lookup(addr, symbolsize, offset,
+						modname, modbuildid, namebuf);
 
 found:
 	cleanup_symbol_name(namebuf);

kernel/trace/ftrace.c

@@ -7046,7 +7046,8 @@ ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
 
 const char *
 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
-		   unsigned long *off, char **modname, char *sym)
+			  unsigned long *off, char **modname,
+			  const unsigned char **modbuildid, char *sym)
 {
 	struct ftrace_mod_map *mod_map;
 	const char *ret = NULL;
@@ -7058,6 +7059,8 @@ ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
 		if (ret) {
 			if (modname)
 				*modname = mod_map->mod->name;
+			if (modbuildid)
+				*modbuildid = module_buildid(mod_map->mod);
 			break;
 		}
 	}