lib/test_lockup.c: fix return value of test_lockup_init()

Since filp_open() returns an error pointer, we should use IS_ERR() to
check the return value and then return PTR_ERR() if failed to get the
actual return value instead of always -EINVAL.

E.g. without this patch:

[root@localhost loongson]# ls no_such_file
ls: cannot access no_such_file: No such file or directory
[root@localhost loongson]# modprobe test_lockup file_path=no_such_file lock_sb_umount time_secs=60 state=S
modprobe: ERROR: could not insert 'test_lockup': Invalid argument
[root@localhost loongson]# dmesg | tail -1
[  126.100596] test_lockup: cannot find file_path

With this patch:

[root@localhost loongson]# ls no_such_file
ls: cannot access no_such_file: No such file or directory
[root@localhost loongson]# modprobe test_lockup file_path=no_such_file lock_sb_umount time_secs=60 state=S
modprobe: ERROR: could not insert 'test_lockup': Unknown symbol in module, or unknown parameter (see dmesg)
[root@localhost loongson]# dmesg | tail -1
[   95.134362] test_lockup: failed to open no_such_file: -2

Fixes: 5908688da884 ("lib/test_lockup.c: add parameters for locking generic vfs locks")
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/1595555407-29875-2-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/test_lockup.c b/lib/test_lockup.c
index 0f81252837b9ca7ae1ea3790d6a1b7703e0fd9e7..f1a020bcc763ed593b583229b39e42f7028e439a 100644 (file)
--- a/lib/test_lockup.c
+++ b/lib/test_lockup.c
@@ -512,8 +512,8 @@ static int __init test_lockup_init(void)
        if (test_file_path[0]) {
                test_file = filp_open(test_file_path, O_RDONLY, 0);
                if (IS_ERR(test_file)) {
-                       pr_err("cannot find file_path\n");
-                       return -EINVAL;
+                       pr_err("failed to open %s: %ld\n", test_file_path, PTR_ERR(test_file));
+                       return PTR_ERR(test_file);
                }
                test_inode = file_inode(test_file);
        } else if (test_lock_inode ||