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xen/blkback: don't free be structure too early 

The be structure must not be freed when freeing the blkif structure
isn't done. Otherwise a use-after-free of be when unmapping the ring
used for communicating with the frontend will occur in case of a
late call of xenblk_disconnect() (e.g. due to an I/O still active
when trying to disconnect).

Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Steven Haigh <netwiz@crc.id.au>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Juergen Gross 2017-05-18 17:28:48 +02:00 committed by Konrad Rzeszutek Wilk
parent 4646441130
commit 71df1d7cca
1 changed files with 3 additions and 4 deletions
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7
drivers/block/xen-blkback/xenbus.c
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@ -315,9 +315,10 @@ static int xen_blkif_disconnect(struct xen_blkif *blkif)
static void xen_blkif_free(struct xen_blkif *blkif)
{
xen_blkif_disconnect(blkif);
WARN_ON(xen_blkif_disconnect(blkif));
xen_vbd_free(&blkif->vbd);
kfree(blkif->be->mode);
kfree(blkif->be);
/* Make sure everything is drained before shutting down */
kmem_cache_free(xen_blkif_cachep, blkif);
@ -514,8 +515,6 @@ static int xen_blkbk_remove(struct xenbus_device *dev)
xen_blkif_put(be->blkif);
}
kfree(be->mode);
kfree(be);
return 0;
}