[PATCH] floppy: fix reference leak on platform_device_register() failure

[Guangshuo Li <lgs201920130244@gmail.com>]

When platform_device_register() fails in do_floppy_init(), the embedded
struct device in floppy_device[drive] has already been initialized by
device_initialize(), but the failure path jumps to out_remove_drives
without dropping the device reference for the current drive.

Previously registered floppy devices are cleaned up in out_remove_drives,
but the device for the drive that fails registration is not, leading to
a reference leak.

The issue was identified by a static analysis tool I developed and
confirmed by manual review. Fix this by calling put_device() for the
current floppy device before jumping to the common cleanup path.

Fixes: 94fd0db7bfb4a ("[PATCH] Floppy: Add cmos attribute to floppy driver")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/block/floppy.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index c28786e0fe1c..d9afe495d5c2 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -4724,8 +4724,10 @@ static int __init do_floppy_init(void)
 		floppy_device[drive].dev.groups = floppy_dev_groups;
 
 		err = platform_device_register(&floppy_device[drive]);
-		if (err)
+		if (err) {
+			put_device(&floppy_device[drive].dev);
 			goto out_remove_drives;
+		}
 
 		registered[drive] = true;
 
-- 
2.43.0