This is a note to let you know that I've just added the patch titled drm/amdgpu: handle the case of pci_channel_io_frozen only in amdgpu_pci_resume to the 5.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-amdgpu-handle-the-case-of-pci_channel_io_frozen-.patch and it can be found in the queue-5.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 136be2316eaac907a905eaa428f5571e61a638ba Author: Guchun Chen <guchun.chen@xxxxxxx> Date: Fri Oct 1 09:48:50 2021 +0800 drm/amdgpu: handle the case of pci_channel_io_frozen only in amdgpu_pci_resume [ Upstream commit 248b061689a40f4fed05252ee2c89f87cf26d7d8 ] 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> Reviewed-by: Andrey Grodzovsky <andrey.grodzovsky@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h index 177a663a6a69..a1c5bd2859fc 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h @@ -1082,6 +1082,7 @@ struct amdgpu_device { bool no_hw_access; struct pci_saved_state *pci_state; + pci_channel_state_t pci_channel_state; struct amdgpu_reset_control *reset_cntl; }; diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c index d3247a5cceb4..d60096b3b2c2 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c @@ -5329,6 +5329,8 @@ pci_ers_result_t amdgpu_pci_error_detected(struct pci_dev *pdev, pci_channel_sta return PCI_ERS_RESULT_DISCONNECT; } + adev->pci_channel_state = state; + switch (state) { case pci_channel_io_normal: return PCI_ERS_RESULT_CAN_RECOVER; @@ -5471,6 +5473,10 @@ 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->pci_channel_state != pci_channel_io_frozen) + return; + for (i = 0; i < AMDGPU_MAX_RINGS; ++i) { struct amdgpu_ring *ring = adev->rings[i];