[PATCH 4.4 38/96] fix a page leak in vhost_scsi_iov_to_sgl() error recovery

Greg Kroah-Hartman
2017-11-28T10:29:42Z

From: Al Viro <viro@zeniv.linux.org.uk>

commit 11d49e9d089ccec81be87c2386dfdd010d7f7f6e upstream.

we are advancing sg as we go, so the pages we need to drop in
case of error are *before* the current sg.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/vhost/scsi.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -703,6 +703,7 @@ vhost_scsi_iov_to_sgl(struct vhost_scsi_
struct scatterlist *sg, int sg_count)
{
size_t off = iter->iov_offset;
+ struct scatterlist *p = sg;
int i, ret;

for (i = 0; i < iter->nr_segs; i++) {
@@ -711,8 +712,8 @@ vhost_scsi_iov_to_sgl(struct vhost_scsi_

ret = vhost_scsi_map_to_sgl(cmd, base, len, sg, write);
if (ret < 0) {
- for (i = 0; i < sg_count; i++) {
- struct page *page = sg_page(&sg[i]);
+ while (p < sg) {
+ struct page *page = sg_page(p++);
if (page)
put_page(page);
}