On 2018å¹´09æ??11æ?¥ 10:51, Emily Deng wrote:
> It will ramdomly have the dead lock issue when test TDR:
> 1. amdgpu_device_handle_vram_lost gets the lock shadow_list_lock
> 2. amdgpu_bo_create locked the bo's resv lock
> 3. amdgpu_bo_create_shadow is waiting for the shadow_list_lock
> 4. amdgpu_device_recover_vram_from_shadow is waiting for the bo's resv
> lock.
>
> v2:
> Make a local copy of the list
>
> Signed-off-by: Emily Deng <Emily.Deng at amd.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 21 ++++++++++++++++++++-
> 1 file changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 2a21267..8c81404 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -3105,6 +3105,9 @@ static int amdgpu_device_handle_vram_lost(struct amdgpu_device *adev)
> long r = 1;
> int i = 0;
> long tmo;
> + struct list_head local_shadow_list;
> +
> + INIT_LIST_HEAD(&local_shadow_list);
>
> if (amdgpu_sriov_runtime(adev))
> tmo = msecs_to_jiffies(8000);
> @@ -3112,8 +3115,19 @@ static int amdgpu_device_handle_vram_lost(struct amdgpu_device *adev)
> tmo = msecs_to_jiffies(100);
>
> DRM_INFO("recover vram bo from shadow start\n");
> +
> + mutex_lock(&adev->shadow_list_lock);
> + list_splice_init(&adev->shadow_list, &local_shadow_list);
> + mutex_unlock(&adev->shadow_list_lock);
> +
> +
> mutex_lock(&adev->shadow_list_lock);
local_shadow_list is a local variable, I think it doesn't need lock at
all, no one change it. Otherwise looks good to me.
Thanks,
David Zhou
> - list_for_each_entry_safe(bo, tmp, &adev->shadow_list, shadow_list) {
> + list_for_each_entry_safe(bo, tmp, &local_shadow_list, shadow_list) {
> + mutex_unlock(&adev->shadow_list_lock);
> +
> + if (!bo)
> + continue;
> +
> next = NULL;
> amdgpu_device_recover_vram_from_shadow(adev, ring, bo, &next);
> if (fence) {
> @@ -3132,9 +3146,14 @@ static int amdgpu_device_handle_vram_lost(struct amdgpu_device *adev)
>
> dma_fence_put(fence);
> fence = next;
> + mutex_lock(&adev->shadow_list_lock);
> }
> mutex_unlock(&adev->shadow_list_lock);
>
> + mutex_lock(&adev->shadow_list_lock);
> + list_splice_init(&local_shadow_list, &adev->shadow_list);
> + mutex_unlock(&adev->shadow_list_lock);
> +
> if (fence) {
> r = dma_fence_wait_timeout(fence, false, tmo);
> if (r == 0)
