CVE-2021-47421: linux kernel — Fix

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.

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-667 CWE-667

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.10 — 5.10.241
linux	linux_kernel	5.11 — 5.14.12
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/248b061689a40f4fed05252ee2c89f87cf26d7d8 https://git.kernel.org/stable/c/72e9a1bf9b722628c28092e0c2cd8717edd201dc https://git.kernel.org/stable/c/785cc093b6b5a93cc350421a55f3f1eda6585156 https://git.kernel.org/stable/c/248b061689a40f4fed05252ee2c89f87cf26d7d8 https://git.kernel.org/stable/c/72e9a1bf9b722628c28092e0c2cd8717edd201dc

Other References

https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html

Frequently Asked Questions

What is CVE-2021-47421? +

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. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-47421? +

CVE-2021-47421 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2021-47421? +

CVE-2021-47421 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2021-47421? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2021-47421