Commit 56cf6504 authored May 05, 2006 by Russell King Committed by Russell King May 05, 2006

[BLOCK] Fix oops on removal of SD/MMC card



The block layer keeps a reference (driverfs_dev) to the struct
device associated with the block device, and uses it internally
for generating uevents in block_uevent.

Block device uevents include umounting the partition, which can
occur after the backing device has been removed.

Unfortunately, this reference is not counted.  This means that
if the struct device is removed from the device tree, the block
layers reference will become stale.

Guard against this by holding a reference to the struct device
in add_disk(), and only drop the reference when we're releasing
the gendisk kobject - in other words when we can be sure that no
further uevents will be generated for this block device.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Jens Axboe <axboe@suse.de>

parent d98550e3

block/genhd.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -182,6 +182,7 @@ static int exact_lock(dev_t dev, void *data)
		*/
		void add_disk(struct gendisk *disk)
		{
		get_device(disk->driverfs_dev);
		disk->flags \|= GENHD_FL_UP;
		blk_register_region(MKDEV(disk->major, disk->first_minor),
		disk->minors, NULL, exact_match, exact_lock, disk);
		@@ -427,6 +428,7 @@ static struct attribute * default_attrs[] = {
		static void disk_release(struct kobject * kobj)
		{
		struct gendisk *disk = to_disk(kobj);
		put_device(disk->driverfs_dev);
		kfree(disk->random);
		kfree(disk->part);
		free_disk_stats(disk);

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