On Thu, 17 Mar 2022, Lee Jones wrote:
> Presently the Client can be freed whilst still in use.
>
> Use the already provided lock to prevent this.
>
> Cc: Felix Kuehling <[email protected]>
> Cc: Alex Deucher <[email protected]>
> Cc: "Christian König" <[email protected]>
> Cc: "Pan, Xinhui" <[email protected]>
> Cc: David Airlie <[email protected]>
> Cc: Daniel Vetter <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Lee Jones <[email protected]>
> ---
I should have clarified here, that:
This patch has only been *build* tested.
Since I have no way to run this on real H/W.
Please ensure this is tested on real H/W before it gets applied, since
it *may* have some undesired side-effects. For instance, I have no
idea if client->lock plays nicely with dev->smi_lock or whether this
may well end up in deadlock.
TIA.
> drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
> b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
> index e4beebb1c80a2..3b9ac1e87231f 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
> @@ -145,8 +145,11 @@ static int kfd_smi_ev_release(struct inode *inode,
> struct file *filep)
> spin_unlock(&dev->smi_lock);
>
> synchronize_rcu();
> +
> + spin_lock(&client->lock);
> kfifo_free(&client->fifo);
> kfree(client);
> + spin_unlock(&client->lock);
>
> return 0;
> }
> @@ -247,11 +250,13 @@ int kfd_smi_event_open(struct kfd_dev *dev, uint32_t
> *fd)
> return ret;
> }
>
> + spin_lock(&client->lock);
> ret = anon_inode_getfd(kfd_smi_name, &kfd_smi_ev_fops, (void *)client,
> O_RDWR);
> if (ret < 0) {
> kfifo_free(&client->fifo);
> kfree(client);
> + spin_unlock(&client->lock);
> return ret;
> }
> *fd = ret;
> @@ -264,6 +269,7 @@ int kfd_smi_event_open(struct kfd_dev *dev, uint32_t *fd)
> spin_lock(&dev->smi_lock);
> list_add_rcu(&client->list, &dev->smi_clients);
> spin_unlock(&dev->smi_lock);
> + spin_unlock(&client->lock);
>
> return 0;
> }
--
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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