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>
This commit is contained in:
Jan Beulich 2021-02-15 08:54:51 +01:00 committed by Greg Kroah-Hartman
parent 0462dbbe2c
commit 8f8ebd6b1c

View File

@ -811,10 +811,8 @@ 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
@ -830,7 +828,7 @@ static int xen_blkbk_map(struct xen_blkif_ring *ring,
gnttab_page_cache_put(&ring->free_pages,
&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;