[PATCH v2] modpost: prevent leak when early return no suffix .o in read_symbols()

[Robertus Diawan Chris <robertusdchris@gmail.com>]

The allocation for elf info symsearch and hdr from parse_elf() haven't
been released when return because of modname didn't have suffix ".o".
And it seems like the suffix ".o" check did not depends on parse_elf()
to succeed first. So, move the suffix ".o" check before checking
parse_elf() result to prevent resource leak when the modname didn't have
suffix ".o" and return early.

This is reported by Coverity Scan as "Resource leak".

Fixes: 8c9ce89c5b63 ("modpost: simplify mod->name allocation")
Signed-off-by: Robertus Diawan Chris <robertusdchris@gmail.com>
---
v1 -> v2:
- Move the suffix ".o" check before parse_elf() instead of adding
  parse_elf_finish() in the suffix ".o" check because the suffix ".o"
  check did not depends on parse_elf() and to minimize overhead handling
  the check (suggested by Nathan Chancellor).
- To make the subject title represents the new change better, change the
  subject title from "modpost: release allocation when early return no
  suffix .o in read_symbols()" to "modpost: prevent leak when early
  return no suffix .o in read_symbols()".

v1:
https://lore.kernel.org/all/20260610052550.187006-1-robertusdchris@gmail.com/

 scripts/mod/modpost.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index abbcd3fc1394..6eb2714521a7 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1580,14 +1580,14 @@ static void read_symbols(const char *modname)
 	struct elf_info info = { };
 	Elf_Sym *sym;
 
-	if (!parse_elf(&info, modname))
-		return;
-
 	if (!strends(modname, ".o")) {
 		error("%s: filename must be suffixed with .o\n", modname);
 		return;
 	}
 
+	if (!parse_elf(&info, modname))
+		return;
+
 	/* strip trailing .o */
 	mod = new_module(modname, strlen(modname) - strlen(".o"));
 

base-commit: 8cd9520d35a6c38db6567e97dd93b1f11f185dc6
-- 
2.54.0