loopdev: remove an user triggerable oops (b1a66504) · Commits · 戴 / test

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:

Guo 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:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Jens Axboe <axboe@kernel.dk>

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)

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