On 1/14/21 8:37 AM, Horace Chen wrote:
Fix a racing issue when jobs on 2 rings timeout simultaneously.
If 2 rings timed out at the same time, the
amdgpu_device_gpu_recover will be reentered. Then the
adev->gmc.xgmi.head will be grabbed by 2 local linked list,
which may cause wild pointer issue in iterating.
lock the device earily to prevent the node be added to 2
different lists.
for xgmi there is a hive lock which can promise there won't have
2 devices on same hive reenter the interation. So xgmi doesn't
need to lock the device.
Note that amdgpu_device_lock_adev does bunch of other stuff besides taking
the lock and I don't think we want to skip them for the other devices in case of
XGMI.
Andrey
Signed-off-by: Horace Chen <horace.chen@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 4d434803fb49..a28e138ac72c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -4591,19 +4591,20 @@ int amdgpu_device_gpu_recover(struct amdgpu_device *adev,
list_rotate_to_front(&adev->gmc.xgmi.head, &hive->device_list);
device_list_handle = &hive->device_list;
} else {
+ /* if current dev is already in reset, skip adding list to prevent race issue */
+ if (!amdgpu_device_lock_adev(adev, hive)) {
+ dev_info(adev->dev, "Bailing on TDR for s_job:%llx, as another already in progress",
+ job ? job->base.id : -1);
+ r = 0;
+ goto skip_recovery;
+ }
+
list_add_tail(&adev->gmc.xgmi.head, &device_list);
device_list_handle = &device_list;
}
/* block all schedulers and reset given job's ring */
list_for_each_entry(tmp_adev, device_list_handle, gmc.xgmi.head) {
- if (!amdgpu_device_lock_adev(tmp_adev, hive)) {
- dev_info(tmp_adev->dev, "Bailing on TDR for s_job:%llx, as another already in progress",
- job ? job->base.id : -1);
- r = 0;
- goto skip_recovery;
- }
-
/*
* Try to put the audio codec into suspend state
* before gpu reset started.
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