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@xxxxxxxx> Tested-by: Steven Haigh <netwiz@xxxxxxxxx> Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> --- This is a backport of upstream commit 71df1d7ccad1c3. --- drivers/block/xen-blkback/xenbus.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index dcabf52425ff..31046c2c39f1 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -316,8 +316,10 @@ 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); @@ -512,8 +514,6 @@ static int xen_blkbk_remove(struct xenbus_device *dev) /* Put the reference we set in xen_blkif_alloc(). */ xen_blkif_put(be->blkif); - kfree(be->mode); - kfree(be); return 0; } -- 2.12.3