gdrom: fix a memory leak bug

BugLink: https://bugs.launchpad.net/bugs/1818813

[ Upstream commit 093c4821 ]

In probe_gdrom(), the buffer pointed by 'gd.cd_info' is allocated through
kzalloc() and is used to hold the information of the gdrom device. To
register and unregister the device, the pointer 'gd.cd_info' is passed to
the functions register_cdrom() and unregister_cdrom(), respectively.
However, this buffer is not freed after it is used, which can cause a
memory leak bug.

This patch simply frees the buffer 'gd.cd_info' in exit_gdrom() to fix the
above issue.
Signed-off-by: Wenwen Wang <wang6495@umn.edu>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

drivers/cdrom/gdrom.c

@@ -882,6 +882,7 @@ static void __exit exit_gdrom(void)
 	platform_device_unregister(pd);
 	platform_driver_unregister(&gdrom_driver);
 	kfree(gd.toc);
+	kfree(gd.cd_info);
 }
 
 module_init(init_gdrom);