[PATCH 5.16 257/285] drm/amdkfd: Create file descriptor after client is added to smi_clients list

Greg Kroah-Hartman
2022-04-12T08:25:57Z

From: Lee Jones <lee.jones@linaro.org>

commit e79a2398e1b2d47060474dca291542368183bc0f upstream.

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>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c | 24 +++++++++++++++---------
1 file changed, 15 insertions(+), 9 deletions(-)

--- a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
@@ -270,15 +270,6 @@ int kfd_smi_event_open(struct kfd_dev *d
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;
@@ -288,5 +279,20 @@ int kfd_smi_event_open(struct kfd_dev *d
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;
}