[PATCH 1/3] Xen/gntdev: don't ignore kernel unmapping error

Demi Marie Obenour
2022-10-30T07:13:28Z

From: Jan Beulich <jbeulich@suse.com>

commit f28347cc66395e96712f5c2db0a302ee75bafce6 upstream.

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: Demi Marie Obenour <demi@invisiblethingslab.com>
Co-authored-by: Demi Marie Obenour <demi@invisiblethingslab.com>
---
drivers/xen/gntdev.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 54fee4087bf1078803c230ad2081aafa8415cf53..8cf9f2074c5d57bff81364d7d6a70b0007a85e44 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -407,6 +407,14 @@ static void __unmap_grant_pages_done(int result,
map->unmap_ops[offset+i].handle,
map->unmap_ops[offset+i].status);
map->unmap_ops[offset+i].handle = -1;
+ if (use_ptemod) {
+ WARN_ON(map->kunmap_ops[offset+i].status &&
+ map->kunmap_ops[offset+i].handle != -1);
+ 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 = -1;
+ }
}
/*
* Decrease the live-grant counter. This must happen after the loop to
--
2.38.1