[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PULL 1/2] xen_disk: mark ioreq as mapped before unmapping in error case
From: Matthew Daley <mattjd@xxxxxxxxx> Commit 4472beae modified the semantics of ioreq_{un,}map so that they are idempotent if called when they're not needed (ie., twice in a row). However, it neglected to handle the case where batch mapping is not being used (the default), and one of the grants fails to map. In this case, ioreq_unmap will be called to unwind and unmap any mappings already performed, but ioreq_unmap simply returns due to the aforementioned change (the ioreq has not already been marked as mapped). The frontend user can therefore force xen_disk to leak grant mappings, a per-domain limited resource. Fix by marking the ioreq as mapped before calling ioreq_unmap in this situation. Signed-off-by: Matthew Daley <mattjd@xxxxxxxxx> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> CC: qemu-stable@xxxxxxxxxx --- hw/block/xen_disk.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c index f35fc59..8742294 100644 --- a/hw/block/xen_disk.c +++ b/hw/block/xen_disk.c @@ -405,6 +405,7 @@ static int ioreq_map(struct ioreq *ioreq) xen_be_printf(&ioreq->blkdev->xendev, 0, "can't map grant ref %d (%s, %d maps)\n", refs[i], strerror(errno), ioreq->blkdev->cnt_map); + ioreq->mapped = 1; ioreq_unmap(ioreq); return -1; } -- 1.7.2.5 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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