Commit 662167e5 authored by Luis Chamberlain's avatar Luis Chamberlain Committed by Jens Axboe
Browse files

floppy: fix calling platform_device_unregister() on invalid drives 



platform_device_unregister() should only be called when
a respective platform_device_register() is called. However
the floppy driver currently allows failures when registring
a drive and a bail out could easily cause an invalid call
to platform_device_unregister() where it was not intended.

Fix this by adding a bool to keep track of when the platform
device was registered for a drive.

This does not fix any known panic / bug. This issue was found
through code inspection while preparing the driver to use the
up and coming support for device_add_disk() error handling.
From what I can tell from code inspection, chances of this
ever happening should be insanely small, perhaps OOM.

Signed-off-by: default avatarLuis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20210927220302.1073499-5-mcgrof@kernel.org


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 3776339a

drivers/block/floppy.c

+7 −2
Original line number Diff line number Diff line
@@ -4479,6 +4479,7 @@ static const struct blk_mq_ops floppy_mq_ops = { 
};



static struct platform_device floppy_device[N_DRIVE];

static bool registered[N_DRIVE];



static bool floppy_available(int drive)

{
@@ -4694,6 +4695,8 @@ static int __init do_floppy_init(void) 
		if (err)

			goto out_remove_drives;



		registered[drive] = true;



		device_add_disk(&floppy_device[drive].dev, disks[drive][0],

				NULL);

	}
@@ -4704,6 +4707,7 @@ static int __init do_floppy_init(void) 
	while (drive--) {

		if (floppy_available(drive)) {

			del_gendisk(disks[drive][0]);

			if (registered[drive])

				platform_device_unregister(&floppy_device[drive]);

		}

	}
@@ -4947,6 +4951,7 @@ static void __exit floppy_module_exit(void) 
				if (disks[drive][i])

					del_gendisk(disks[drive][i]);

			}

			if (registered[drive])

				platform_device_unregister(&floppy_device[drive]);

		}

		for (i = 0; i < ARRAY_SIZE(floppy_type); i++) {