> Because device_del() will put reference count of the parent, and the patch > only focuses on race between probe/release and shutdown.
Right. device_del() puts the reference count of the parent -- is it guaranteed that device_del() won't ever reassign dev->parent though (e.g., to NULL)? I don't think it is, so I think that patch should also save the pointer to the parent and use it (instead of what happens to be in than dev->parent) to release the lock and put the ref. > As far as device_move() concerned, looks it might be a problem. > The problem even exits on driver attach vs. device open/release, > if device_move is called in open() and open() happens before driver > attach completes. Yeah, the pattern of locking the parent followed by the device occurs in a few places. It looks like they were added by Alan with commit bf74ad5bc41727d5f2f1c6bedb2c1fac394de731. (And as Greg mentioned, might be occurring often enough to merit being moved into a common function.) I guess the question is whether the callee is allowed to call device_move(), if not, we're good. > Your concern on device_remove() might be correct. Also, I am wondering > if we can walk the 'dpm_list' backwards for device shutdown, which should > be simpler and more reasonable. How would that help? -- 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/
