# CVE-2021-47577: linux: In the Linux kernel, the following vulnerability has been resolved:  io-wq: check for wq exit after adding new worker...

CVE-2021-47577 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47577, released June 19, 2024. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-47577
- Priority: Routine
- CVSS: 4.7 (medium)
- EPSS: 0.0015
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 19, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  io-wq: check for wq exit after adding new worker task_work  We check IO_WQ_BIT_EXIT before attempting to create a new worker, and wq exit cancels pending work if we have any. But it's possible to have a race between the two, where creation checks exit finding it not set, but we're in the process of exiting. The exit side will cancel pending creation task_work, but there's a gap where we add task_work after we've canceled existing creations at exit time.  Fix this by checking the EXIT bit post adding the creation task_work. If it's set, run the same cancelation that exit does.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.15.15-1 | [DEBIAN-CVE-2021-47577](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47577.md) | Jun 19, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.15.15-1 | [DEBIAN-CVE-2021-47577](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47577.md) | Jun 19, 2024 |
| Linux | linux Debian 14 | 5.15.15-1 | [DEBIAN-CVE-2021-47577](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47577.md) | Jun 19, 2024 |

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