Commit a01b49a9 authored Feb 15, 2021 by Jan Beulich Committed by Greg Kroah-Hartman Feb 23, 2021

xen-blkback: don't "handle" error by BUG()



commit 5a264285ed1cd32e26d9de4f3c8c6855e467fd63 upstream.

In particular -ENOMEM may come back here, from set_foreign_p2m_mapping().
Don't make problems worse, the more that handling elsewhere (together
with map's status fields now indicating whether a mapping wasn't even
attempted, and hence has to be considered failed) doesn't require this
odd way of dealing with errors.

This is part of XSA-362.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 271a3984

drivers/block/xen-blkback/blkback.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -867,10 +867,8 @@ static int xen_blkbk_map(struct xen_blkif_ring *ring,
		break;
		}

		if (segs_to_map) {
		if (segs_to_map)
		ret = gnttab_map_refs(map, NULL, pages_to_gnt, segs_to_map);
		BUG_ON(ret);
		}

		/*
		* Now swizzle the MFN in our domain with the MFN from the other domain
		@@ -885,7 +883,7 @@ static int xen_blkbk_map(struct xen_blkif_ring *ring,
		pr_debug("invalid buffer -- could not remap it\n");
		put_free_pages(ring, &pages[seg_idx]->page, 1);
		pages[seg_idx]->handle = BLKBACK_INVALID_HANDLE;
		ret \|= 1;
		ret \|= !ret;
		goto next;
		}
		pages[seg_idx]->handle = map[new_map_idx].handle;