Re: [PATCH 2/2] vhost-vdpa: set v->config_ctx to NULL if eventfd_ctx_fdget() fails

[Jason Wang]

On 2021/3/11 9:52 下午, Stefano Garzarella wrote:

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....@intel.com
Cc: sta...@vger.kernel.org
Signed-off-by: Stefano Garzarella <sgarz...@redhat.com>

Acked-by: Jason Wang <jasow...@redhat.com>

---
  drivers/vhost/vdpa.c | 8 ++++++--
  1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 00796e4ecfdf..f9ecdce5468a 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -331,8 +331,12 @@ static long vhost_vdpa_set_config_call(struct vhost_vdpa 
*v, u32 __user *argp)
        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);