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| author | Luis Chamberlain <mcgrof@kernel.org> | 2021-09-28 01:02:52 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-11-18 21:16:16 +0300 |
| commit | 22b68b015d44e249b04b7c77b269991922d46bc4 (patch) | |
| tree | 8129082b3d8975959b83840c3f1d751f5e5c2bd2 | |
| parent | 396c9e834d6981164fa112c4bcf97283cf2410e0 (diff) | |
| download | linux-22b68b015d44e249b04b7c77b269991922d46bc4.tar.xz | |
floppy: fix calling platform_device_unregister() on invalid drives
[ 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>
| -rw-r--r-- | drivers/block/floppy.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index fef79ea52e3e..fb2aafabfebc 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]) |