[PATCH 6.18 264/277] kallsyms: clean up modname and modbuildid initialization in kallsyms_lookup_buildid()

Greg Kroah-Hartman
2026-04-08T18:38:38Z

From: Petr Mladek <pmladek@suse.com>

commit fda024fb64769e9d6b3916d013c78d6b189129f8 upstream.

The @modname and @modbuildid optional return parameters are set only when
the symbol is in a module.

Always initialize them so that they do not need to be cleared when the
module is not in a module. It simplifies the logic and makes the code
even slightly more safe.

Note that bpf_address_lookup() function will get updated in a separate
patch.

Link: https://lkml.kernel.org/r/20251128135920.217303-3-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Aaron Tomlin <atomlin@atomlin.com>
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>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/kallsyms.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -362,6 +362,14 @@ static int kallsyms_lookup_buildid(unsig
* or empty string.
*/
namebuf[0] = 0;
+ /*
+ * Initialize the module-related return values. They are not set
+ * when the symbol is in vmlinux or it is a bpf address.
+ */
+ if (modname)
+ *modname = NULL;
+ if (modbuildid)
+ *modbuildid = NULL;

if (is_ksym_addr(addr)) {
unsigned long pos;
@@ -370,10 +378,6 @@ static int kallsyms_lookup_buildid(unsig
/* Grab name */
kallsyms_expand_symbol(get_symbol_offset(pos),
namebuf, KSYM_NAME_LEN);
- if (modname)
- *modname = NULL;
- if (modbuildid)
- *modbuildid = NULL;

return strlen(namebuf);
}