CVE-2021-47192

Medium

In the Linux kernel, the following vulnerability has been resolved: scsi: core: sysfs: Fix hang when device state is set via sysfs This fixes a regression added with: commit f0f82e2476f6 ("scsi: core: Fix capacity set to zero after offlinining device") The problem is that after iSCSI recovery, iscsid will call into the kernel to set the dev's state to running, and with that patch we now call scsi_rescan_device() with the state_mutex held. If the SCSI error handler thread is just starting to test the device in scsi_send_eh_cmnd() then it's going to try to grab the state_mutex. We are then stuck, because when scsi_rescan_device() tries to send its I/O scsi_queue_rq() calls -> scsi_host_queue_ready() -> scsi_host_in_recovery() which will return true (the host state is still in recovery) and I/O will just be requeued. scsi_send_eh_cmnd() will then never be able to grab the state_mutex to finish error handling. To prevent the deadlock move the rescan-related code to after we drop the state_mutex. This also adds a check for if we are already in the running state. This prevents extra scans and helps the iscsid case where if the transport class has already onlined the device during its recovery process then we don't need userspace to do it again plus possibly block that daemon.

Package Linux Kernel
Published 2024-04-10
Last modified 2025-04-30
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

5.3

out of 10
Medium
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Weakness type

CWE-667

CVE-2021-47192 is a Improper Locking vulnerability

What is Improper Locking?

The product does not properly acquire or release a lock, which can lead to unexpected behaviour. Learn more on MITRE CWE

Affected versions

Linux kernel versions 5.4.143, 5.10.61, 5.13.13, 5.14 and later are affected. Fixed in 5.4.162, 5.10.82, 5.15.5, 5.16 and their respective stable series.

Affected from
≥ 5.4.143 ≥ 5.10.61 ≥ 5.13.13 ≥ 5.14
Fixed in
✓ 5.4.162 5.4.x ✓ 5.10.82 5.10.x ✓ 5.15.5 5.15.x ✓ 5.16

References

4 total

Frequently asked questions

  • What is CVE-2021-47192?

    CVE-2021-47192 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.3 out of 10 , classified as an Improper Locking flaw (CWE-667) . It affects Linux kernel versions from 5.4.143 onward and has been patched in 5.4.162, 5.10.82, 5.15.5 and others. CVE-2021-47192 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2021-47192?

    CVE-2021-47192 has a CVSS score of 5.3 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N .

  • Is there a patch available for CVE-2021-47192?

    Yes. CVE-2021-47192 has been patched. Fixed versions include 5.4.162, 5.10.82, 5.15.5 and others. If you are running Linux kernel 5.4.143 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2021-47192 actively exploited?

    No. CVE-2021-47192 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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