CVE-2021-47577 io-wq: check for wq exit after adding new worker task_work

2024-06-1914:53:45

Linux

github.com

linux kernel

vulnerability

io-wq

6.8 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

9.1%

JSON

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.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "fs/io-wq.c"
    ],
    "versions": [
      {
        "version": "1da177e4c3f4",
        "lessThan": "4b4e5bbf9386",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "71a85387546e",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "fs/io-wq.c"
    ],
    "versions": [
      {
        "version": "5.15.11",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.16",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]