On 2021-10-02 11:18 a.m., Guchun Chen wrote:
In current code, when a PCI error state pci_channel_io_normal is detectd,
it will report PCI_ERS_RESULT_CAN_RECOVER status to PCI driver, and PCI
driver will continue the execution of PCI resume callback report_resume by
pci_walk_bridge, and the callback will go into amdgpu_pci_resume
finally, where write lock is releasd unconditionally without acquiring
such lock first. In this case, a deadlock will happen when other threads
start to acquire the read lock.
To fix this, add a member in amdgpu_device strucutre to cache
pci_channel_state, and only continue the execution in amdgpu_pci_resume
when it's pci_channel_io_frozen.
Fixes: c9a6b82f45e2("drm/amdgpu: Implement DPC recovery")
Suggested-by: Andrey Grodzovsky <andrey.grodzovsky@xxxxxxx>
Signed-off-by: Guchun Chen <guchun.chen@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu.h | 1 +
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 6 ++++++
2 files changed, 7 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index f4bceb2624fb..720d0ccecfe0 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1094,6 +1094,7 @@ struct amdgpu_device {
bool no_hw_access;
struct pci_saved_state *pci_state;
+ pci_channel_state_t cached_state;
I would give a more descriptive name to this (e.g. pci_channel_state)
Other then that Reviewed-by: Andrey Grodzovsky <andrey.grodzovsky@xxxxxxx>
Andrey
struct amdgpu_reset_control *reset_cntl;
uint32_t ip_versions[HW_ID_MAX][HWIP_MAX_INSTANCE];
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index bb5ad2b6ca13..1aaeb4b30edc 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -5368,6 +5368,8 @@ pci_ers_result_t amdgpu_pci_error_detected(struct pci_dev *pdev, pci_channel_sta
return PCI_ERS_RESULT_DISCONNECT;
}
+ adev->cached_state = state;
+
switch (state) {
case pci_channel_io_normal:
return PCI_ERS_RESULT_CAN_RECOVER;
@@ -5510,6 +5512,10 @@ void amdgpu_pci_resume(struct pci_dev *pdev)
DRM_INFO("PCI error: resume callback!!\n");
+ /* Only continue execution for the case of pci_channel_io_frozen */
+ if (adev->cached_state != pci_channel_io_frozen)
+ return;
+
for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
struct amdgpu_ring *ring = adev->rings[i];
