# CVE-2021-47622: scsi: ufs: Fix a deadlock in the error handler

> A deadlock in the Linux kernel SCSI UFS error handler can cause a system hang, requiring a patch to fix the resource allocation logic.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Jul 2024
- **Updated:** 23 May 2026
- **Also known as:** DEBIAN-CVE-2021-47622, GHSA-m484-77r4-h4vf, ROOT-OS-DEBIAN-11-CVE-2021-47622, UBUNTU-CVE-2021-47622

## What is CVE-2021-47622?

CVE-2021-47622 is a medium-severity denial of service vulnerability in Linux kernel, published on 16 Jul 2024. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

scsi: ufs: Fix a deadlock in the error handler

The following deadlock has been observed on a test setup:

 - All tags allocated

 - The SCSI error handler calls ufshcd_eh_host_reset_handler()

 - ufshcd_eh_host_reset_handler() queues work that calls
   ufshcd_err_handler()

 - ufshcd_err_handler() locks up as follows:

Workqueue: ufs_eh_wq_0 ufshcd_err_handler.cfi_jt
Call trace:
 __switch_to+0x298/0x5d8
 __schedule+0x6cc/0xa94
 schedule+0x12c/0x298
 blk_mq_get_tag+0x210/0x480
 __blk_mq_alloc_request+0x1c8/0x284
 blk_get_request+0x74/0x134
 ufshcd_exec_dev_cmd+0x68/0x640
 ufshcd_verify_dev_init+0x68/0x35c
 ufshcd_probe_hba+0x12c/0x1cb8
 ufshcd_host_reset_and_restore+0x88/0x254
 ufshcd_reset_and_restore+0xd0/0x354
 ufshcd_err_handler+0x408/0xc58
 process_one_work+0x24c/0x66c
 worker_thread+0x3e8/0xa4c
 kthread+0x150/0x1b4
 ret_from_fork+0x10/0x30

Fix this lockup by making ufshcd_exec_dev_cmd() allocate a reserved
request.

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2021-47622?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-47622?

Apply the vendor's patch.

## Is CVE-2021-47622 being exploited?

There is no known exploitation of CVE-2021-47622 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-47622 and fix it if it is affected.

What it is: CVE-2021-47622 is a medium-severity denial of service vulnerability in Linux kernel, published on 16 Jul 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-47622 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-47622/ (Markdown: https://insights.sbomify.com/CVE-2021-47622/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47622
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47622
- OSV: https://osv.dev/vulnerability/CVE-2021-47622

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47622/
Summaries are generated and may contain mistakes; the official description above is the record.