| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2021-47421: drm/amdgpu: handle the case of pci_channel_io_frozen only in amdgpu_pci_resume |
| |
| 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. |
| |
| The Linux kernel CVE team has assigned CVE-2021-47421 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.10 with commit c9a6b82f45e261d247b980a7949aaa6a9bfffe01 and fixed in 5.14.12 with commit 72e9a1bf9b722628c28092e0c2cd8717edd201dc |
| Issue introduced in 5.10 with commit c9a6b82f45e261d247b980a7949aaa6a9bfffe01 and fixed in 5.15 with commit 248b061689a40f4fed05252ee2c89f87cf26d7d8 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2021-47421 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| drivers/gpu/drm/amd/amdgpu/amdgpu.h |
| drivers/gpu/drm/amd/amdgpu/amdgpu_device.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/72e9a1bf9b722628c28092e0c2cd8717edd201dc |
| https://git.kernel.org/stable/c/248b061689a40f4fed05252ee2c89f87cf26d7d8 |
