Messages in this thread | | | Date | Tue, 4 Dec 2012 19:21:51 +0100 | From | Olaf Hering <> | Subject | Re: [PATCH] xen/blkback: do not leak mode property |
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On Tue, Dec 04, Jan Beulich wrote:
> This looks necessary but insufficient - there's nothing really > preventing backend_changed() from being called more than once > for a given device (is simply the handler of xenbus watch). Hence > I think either that function needs to be guarded against multiple > execution (e.g. by removing the watch from that function itself, > if that's permitted by xenbus), or to properly deal with the > effects this has (including but probably not limited to the leaking > of be->mode).
If another watch does really trigger after the kfree(be) in xen_blkbk_remove(), wouldnt backend_changed access stale memory? So if that can really happen in practice, shouldnt the backend_watch be a separate allocation instead being contained within backend_info?
Looking at unregister_xenbus_watch, it clears removes the watch from the list, so that process_msg will not see it anymore.
Olaf
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