[PATCH 5.10 022/157] vhost-vdpa: set v->config_ctx to NULL if eventfd_ctx_fdget() fails

Greg Kroah-Hartman
2021-03-22T12:41:56Z

From: Stefano Garzarella <sgarzare@redhat.com>

commit 0bde59c1723a29e294765c96dbe5c7fb639c2f96 upstream.

In vhost_vdpa_set_config_call() if eventfd_ctx_fdget() fails the
'v->config_ctx' contains an error instead of a valid pointer.

Since we consider 'v->config_ctx' valid if it is not NULL, we should
set it to NULL in this case to avoid to use an invalid pointer in
other functions such as vhost_vdpa_config_put().

Fixes: 776f395004d8 ("vhost_vdpa: Support config interrupt in vdpa")
Cc: lingshan.zhu@intel.com
Cc: stable@vger.kernel.org
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20210311135257.109460-3-sgarzare@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/vhost/vdpa.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -335,8 +335,12 @@ static long vhost_vdpa_set_config_call(s
if (!IS_ERR_OR_NULL(ctx))
eventfd_ctx_put(ctx);

- if (IS_ERR(v->config_ctx))
- return PTR_ERR(v->config_ctx);
+ if (IS_ERR(v->config_ctx)) {
+ long ret = PTR_ERR(v->config_ctx);
+
+ v->config_ctx = NULL;
+ return ret;
+ }

v->vdpa->config->set_config_cb(v->vdpa, &cb);