floppy: fix another use-after-free

While scanning the floopy code due to c093ee4f07f4 ("floppy: fix
use-after-free in module load failure path"), I found one more instance
of trying to access disk->queue pointer after doing put_disk() on
gendisk.  For some reason , floppy moule still loads/unloads fine.  The
object is probably still around with right pointer values.

 o There seems to be one more instance of trying to cleanup the request
   queue after we have called put_disk() on associated gendisk.

 o This fix is more out of code inspection.  Even without this fix for
   some reason I am able to load/unload floppy module without any
   issues.

 o Floppy module loads/unloads fine after the fix.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 8f19b38..3951020 100644 (file)
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -4573,8 +4573,8 @@ static void __exit floppy_module_exit(void)
                        device_remove_file(&floppy_device[drive].dev, &dev_attr_cmos);
                        platform_device_unregister(&floppy_device[drive]);
                }
-               put_disk(disks[drive]);
                blk_cleanup_queue(disks[drive]->queue);
+               put_disk(disks[drive]);
        }
 
        del_timer_sync(&fd_timeout);