CVE-2022-50335 9p: set req refcount to zero to avoid uninitialized usage

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/9p/client.c"
    ],
    "versions": [
      {
        "version": "728356dedeff8ef999cb436c71333ef4ac51a81c",
        "lessThan": "1cabce56626a61f4f02452cba61ad4332a4b73f8",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "728356dedeff8ef999cb436c71333ef4ac51a81c",
        "lessThan": "73c47b3123b351de2d3714a72a336c0f72f203af",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "728356dedeff8ef999cb436c71333ef4ac51a81c",
        "lessThan": "967fc34f297e40fd2e068cf6b0c3eb4916228539",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "728356dedeff8ef999cb436c71333ef4ac51a81c",
        "lessThan": "26273ade77f54716e30dfd40ac6e85ceb54ac0f9",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "3665a4d9dca1bd06bc34afb72e637fe01b2776ee",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "4.19.57",
        "lessThan": "4.20",
        "status": "affected",
        "versionType": "semver"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/9p/client.c"
    ],
    "versions": [
      {
        "version": "4.20",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "4.20",
        "status": "unaffected",
        "versionType": "semver"
      },
      {
        "version": "5.15.86",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "semver"
      },
      {
        "version": "6.0.16",
        "lessThanOrEqual": "6.0.*",
        "status": "unaffected",
        "versionType": "semver"
      },
      {
        "version": "6.1.2",
        "lessThanOrEqual": "6.1.*",
        "status": "unaffected",
        "versionType": "semver"
      },
      {
        "version": "6.2",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]