CVE ID:	CVE-2021-47421
Description:	In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: handle the case of pci_channel_io_frozen only in amdgpu_pci_resume 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.
Test IDs:	None available
Cross References:	Common Vulnerability Exposure (CVE) ID: CVE-2021-47421 https://git.kernel.org/stable/c/248b061689a40f4fed05252ee2c89f87cf26d7d8 https://git.kernel.org/stable/c/248b061689a40f4fed05252ee2c89f87cf26d7d8 https://git.kernel.org/stable/c/72e9a1bf9b722628c28092e0c2cd8717edd201dc https://git.kernel.org/stable/c/72e9a1bf9b722628c28092e0c2cd8717edd201dc