[PATCH 4.4 32/35] xen-scsiback: dont "handle" error by BUG()

Greg Kroah-Hartman
2021-02-22T13:39:26Z

From: Jan Beulich <jbeulich@suse.com>

commit 7c77474b2d22176d2bfb592ec74e0f2cb71352c9 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>

---
drivers/xen/xen-scsiback.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/xen/xen-scsiback.c
+++ b/drivers/xen/xen-scsiback.c
@@ -415,12 +415,12 @@ static int scsiback_gnttab_data_map_batc
return 0;

err = gnttab_map_refs(map, NULL, pg, cnt);
- BUG_ON(err);
for (i = 0; i < cnt; i++) {
if (unlikely(map[i].status != GNTST_okay)) {
pr_err("invalid buffer -- could not remap it\n");
map[i].handle = SCSIBACK_INVALID_HANDLE;
- err = -ENOMEM;
+ if (!err)
+ err = -ENOMEM;
} else {
get_page(pg[i]);
}