From: Luis Chamberlain mcgrof@kernel.org
[ Upstream commit 662167e59d2f3c15a44a88088fc6c1a67c8a3650 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/block/floppy.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 9538146e520e0..3592a6277d0bb 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -4478,6 +4478,7 @@ 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) { @@ -4693,6 +4694,8 @@ 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); } @@ -4703,7 +4706,8 @@ 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: @@ -4946,7 +4950,8 @@ 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])