[PATCH] tty: vt: keyboard: Fix uninitialized variables in vt_do_kdgkb_ioctl

[Purva Yeshi]

Fix Smatch-detected issue:

drivers/tty/vt/keyboard.c:2106 vt_do_kdgkb_ioctl() error:
uninitialized symbol 'kbs'.
drivers/tty/vt/keyboard.c:2108 vt_do_kdgkb_ioctl() error:
uninitialized symbol 'ret'.

Fix uninitialized variable warnings reported by Smatch in
vt_do_kdgkb_ioctl(). The variables kbs and ret were used in the kfree
and return statements without guaranteed initialization paths, leading to
potential undefined behavior or false positives during static analysis.

Initialize char *kbs to NULL and int ret to -EINVAL at declaration.
This ensures safe use of kfree(kbs) and return ret regardless of control
flow. Also add a default case in the switch to preserve fallback behavior.

Signed-off-by: Purva Yeshi <purvayeshi550@xxxxxxxxx>
---
 drivers/tty/vt/keyboard.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
index ae92e6a50a65..d476c2e3f3d3 100644
--- a/drivers/tty/vt/keyboard.c
+++ b/drivers/tty/vt/keyboard.c
@@ -2057,8 +2057,8 @@ int vt_do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm)
 {
 	unsigned char kb_func;
 	unsigned long flags;
-	char *kbs;
-	int ret;
+	char *kbs = NULL;
+	int ret = -EINVAL;
 
 	if (get_user(kb_func, &user_kdgkb->kb_func))
 		return -EFAULT;
@@ -2101,6 +2101,10 @@ int vt_do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm)
 
 		ret = 0;
 		break;
+
+	default:
+		/* unknown command, ret already set to -EINVAL */
+		break;
 	}
 
 	kfree(kbs);
-- 
2.34.1