drm/amdkfd: Create file descriptor after client is added to smi_clients list

This ensures userspace cannot prematurely clean-up the client before
it is fully initialised which has been proven to cause issues in the
past.

Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
index e4beebb1c80a21ed62b5c0abca0a373aed9bce35..f2e1d506ba211f04c35104e692d5bb197dc0df10 100644 (file)
--- a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
@@ -247,15 +247,6 @@ int kfd_smi_event_open(struct kfd_dev *dev, uint32_t *fd)
                return ret;
        }
 
-       ret = anon_inode_getfd(kfd_smi_name, &kfd_smi_ev_fops, (void *)client,
-                              O_RDWR);
-       if (ret < 0) {
-               kfifo_free(&client->fifo);
-               kfree(client);
-               return ret;
-       }
-       *fd = ret;
-
        init_waitqueue_head(&client->wait_queue);
        spin_lock_init(&client->lock);
        client->events = 0;
@@ -265,5 +256,20 @@ int kfd_smi_event_open(struct kfd_dev *dev, uint32_t *fd)
        list_add_rcu(&client->list, &dev->smi_clients);
        spin_unlock(&dev->smi_lock);
 
+       ret = anon_inode_getfd(kfd_smi_name, &kfd_smi_ev_fops, (void *)client,
+                              O_RDWR);
+       if (ret < 0) {
+               spin_lock(&dev->smi_lock);
+               list_del_rcu(&client->list);
+               spin_unlock(&dev->smi_lock);
+
+               synchronize_rcu();
+
+               kfifo_free(&client->fifo);
+               kfree(client);
+               return ret;
+       }
+       *fd = ret;
+
        return 0;
 }