[PATCH] 2.5.44 Fix uninitialized device struct w/ add_disk()

From: Andres Salomon (dilinger@mp3revolution.net)
Date: Sat Oct 19 2002 - 03:11:01 EST


This occurs w/ 2.5 device-mapper; add_disk() is called (w/ a possibly
invalid gendisk). add_disk() calls register_disk(), which constructs
the device struct (gendisk::disk_dev). First, the bus_id field is
initialized, and then device_add() is called. However, device_add()
does no initialization of the device struct. So, since the
gendisk::disk_dev::parent list is NULL, the gendisk::disk_dev::node
field is never initialized. Later on in device_add(), if an error has
occurred, list_del_init(&dev->node) is called; dev->node is {NULL,NULL},
and an oops occurs.

Instead of calling device_add(), my patch makes register_disk() call
device_register(). This appear to do the same thing as device_add(),
but initializes the device struct before calling device_add().

-- 
It's not denial.  I'm just selective about the reality I accept.
	-- Bill Watterson


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