On Mon, 19 Nov 2007 10:53:40 -0500 (EST) Alan Stern <[EMAIL PROTECTED]> wrote:
> This patch (as1015) reverts changes that were made to the driver core > about four years ago. The intent back then was to avoid certain kinds > of invalid memory accesses by leaving kernel objects allocated as long > as any of their children were still allocated. The original and > correct approach was to wait only as long as any children were still > _registered_; that's what this patch reinstates. What happened with this? > This fixes a problem in the SCSI core made visible by the class_device > to regular device conversion: A reference loop (scsi_device holds > reference to request_queue, which is the child of a gendisk, which is > the child of the scsi_device) prevents the data structures from being > released, even though they are deregistered okay. > > It's possible that this change will cause a few bugs to surface, > things that have been hidden for several years. They can be fixed > easily enough by having the child device take an explicit reference to > the parent whenever needed. > How will such bugs manifest? Ideally via a nice printk and a stack trace followed by damage avoidance. If it's via a mysterious crash or something similarly obscure then can we improve that? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/