[PATCH 5.14 27/48] Xen/gntdev: dont ignore kernel unmapping error

Greg Kroah-Hartman
2021-10-08T11:38:08Z

From: Jan Beulich <jbeulich@suse.com>

[ Upstream commit f28347cc66395e96712f5c2db0a302ee75bafce6 ]

While working on XSA-361 and its follow-ups, I failed to spot another
place where the kernel mapping part of an operation was not treated the
same as the user space part. Detect and propagate errors and add a 2nd
pr_debug().

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/c2513395-74dc-aea3-9192-fd265aa44e35@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/xen/gntdev.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index a3e7be96527d..23fd09a9bbaf 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -396,6 +396,14 @@ static int __unmap_grant_pages(struct gntdev_grant_map *map, int offset,
map->unmap_ops[offset+i].handle,
map->unmap_ops[offset+i].status);
map->unmap_ops[offset+i].handle = INVALID_GRANT_HANDLE;
+ if (use_ptemod) {
+ if (map->kunmap_ops[offset+i].status)
+ err = -EINVAL;
+ pr_debug("kunmap handle=%u st=%d\n",
+ map->kunmap_ops[offset+i].handle,
+ map->kunmap_ops[offset+i].status);
+ map->kunmap_ops[offset+i].handle = INVALID_GRANT_HANDLE;
+ }
}
return err;
}
--
2.33.0