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floppy: fix calling platform_device_unregister() on invalid drives

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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: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20210927220302.1073499-5-mcgrof@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Luis Chamberlain 2021-09-27 15:02:52 -07:00 committed by Jens Axboe
parent 3776339ae7
commit 662167e59d
1 changed files with 7 additions and 2 deletions
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9
drivers/block/floppy.c
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@ -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);
}
@ -4704,7 +4707,8 @@ out_remove_drives:
while (drive--) {
if (floppy_available(drive)) {
del_gendisk(disks[drive][0]);
platform_device_unregister(&floppy_device[drive]);
if (registered[drive])
platform_device_unregister(&floppy_device[drive]);
}
}
out_release_dma:
@ -4947,7 +4951,8 @@ static void __exit floppy_module_exit(void)
if (disks[drive][i])
del_gendisk(disks[drive][i]);
}
platform_device_unregister(&floppy_device[drive]);
if (registered[drive])
platform_device_unregister(&floppy_device[drive]);
}
for (i = 0; i < ARRAY_SIZE(floppy_type); i++) {
if (disks[drive][i])