[AMD Official Use Only - Internal Distribution Only]
Reviewed-by: Evan Quan <evan.quan@xxxxxxx>
-----Original Message-----
From: Horace Chen <horace.chen@xxxxxxx>
Sent: Thursday, January 14, 2021 9:37 PM
To: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: Grodzovsky, Andrey <Andrey.Grodzovsky@xxxxxxx>; Quan, Evan <Evan.Quan@xxxxxxx>; Chen, Horace <Horace.Chen@xxxxxxx>; Tuikov, Luben <Luben.Tuikov@xxxxxxx>; Koenig, Christian <Christian.Koenig@xxxxxxx>; Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Xiao, Jack <Jack.Xiao@xxxxxxx>; Zhang, Hawking <Hawking.Zhang@xxxxxxx>; Liu, Monk <Monk.Liu@xxxxxxx>; Xu, Feifei <Feifei.Xu@xxxxxxx>; Wang, Kevin(Yang) <Kevin1.Wang@xxxxxxx>; Xiaojie Yuan <xiaojie.yuan@xxxxxxx>
Subject: [PATCH 1/2] drm/amdgpu: race issue when jobs on 2 ring timeout
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.
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.
--
2.17.1
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