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Commit b1a66504 authored by Guo Chao's avatar Guo Chao Committed by Jens Axboe
Browse files

loopdev: remove an user triggerable oops 



When loopdev is built as module and we pass an invalid parameter,
loop_init() will return directly without deregister misc device, which
will cause an oops when insert loop module next time because we left some
garbage in the misc device list.

Test case:
sudo modprobe loop max_part=1024
(failed due to invalid parameter)
sudo modprobe loop
(oops)

Clean up nicely to avoid such oops.

Signed-off-by: default avatarGuo Chao <yan@linux.vnet.ibm.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Guo Chao <yan@linux.vnet.ibm.com>
Cc: M. Hindess <hindessm@uk.ibm.com>
Cc: Nikanth Karthikesan <knikanth@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 7b0576a3

drivers/block/loop.c

+16 −6
Original line number Diff line number Diff line
@@ -1844,11 +1844,15 @@ static int __init loop_init(void) 
		max_part = (1UL << part_shift) - 1;

	}



	if ((1UL << part_shift) > DISK_MAX_PARTS)

		return -EINVAL;

	if ((1UL << part_shift) > DISK_MAX_PARTS) {

		err = -EINVAL;

		goto misc_out;

	}



	if (max_loop > 1UL << (MINORBITS - part_shift))

		return -EINVAL;

	if (max_loop > 1UL << (MINORBITS - part_shift)) {

		err = -EINVAL;

		goto misc_out;

	}



	/*

	 * If max_loop is specified, create that many devices upfront.
@@ -1866,8 +1870,10 @@ static int __init loop_init(void) 
		range = 1UL << MINORBITS;

	}



	if (register_blkdev(LOOP_MAJOR, "loop"))

		return -EIO;

	if (register_blkdev(LOOP_MAJOR, "loop")) {

		err = -EIO;

		goto misc_out;

	}



	blk_register_region(MKDEV(LOOP_MAJOR, 0), range,

				  THIS_MODULE, loop_probe, NULL, NULL);
@@ -1880,6 +1886,10 @@ static int __init loop_init(void) 


	printk(KERN_INFO "loop: module loaded\n");

	return 0;



misc_out:

	misc_deregister(&loop_misc);

	return err;

}



static int loop_exit_cb(int id, void *ptr, void *data)