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btrfs: do not strictly require dirty metadata threshold for metadata writepages

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: btrfs: do not strictly require dirty metadata threshold for metadata writepages [BUG] There is an internal report that over 1000 processes are waiting at the io_schedule_timeout() of balance_dirty_pages(), causing a system hang and trigger a kernel coredump. The kernel is v6.4 kernel based, but the root problem still applies to any upstream kernel before v6.18. [CAUSE] From Jan Kara for his wisdom on the dirty page balance behavior first. This cgroup dirty limit was what was actually playing the role here because the cgroup had only a small amount of memory and so the dirty limit for it was something like 16MB. Dirty throttling is responsible for enforcing that nobody can dirty (significantly) more dirty memory than there's dirty limit. Thus when a task is dirtying pages it periodically enters into balance_dirty_pages() and we let it sleep there to slow down the dirtying. When the system is over dirty limit already (either globally or within a cgroup of the running task), we will not let the task exit from balance_dirty_pages() until the number of dirty pages drops below the limit. So in this particular case, as I already mentioned, there was a cgroup with relatively small amount of memory and as a result with dirty limit set at 16MB. A task from that cgroup has dirtied about 28MB worth of pages in btrfs btree inode and these were practically the only dirty pages in that cgroup. So that means the only way to

Announced Source revision 1
Original source ↗

CVE-2026-23157

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-23157

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "793955bca66c99defdffc857ae6eb7e8431d6bbe",
        "lessThan": "6a8b6242eaa1dd7a0de2d6de6420d10ffe68db90",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "793955bca66c99defdffc857ae6eb7e8431d6bbe",
        "lessThan": "bb9be3f713652e330df00f3724c18c7a5469e7ac",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "793955bca66c99defdffc857ae6eb7e8431d6bbe",
        "lessThan": "4357e02cafabe01c2d737ceb4c4c6382fc2ee10a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "793955bca66c99defdffc857ae6eb7e8431d6bbe",
        "lessThan": "0c3666ec188640c20e254011e7adf4464c32ee58",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "793955bca66c99defdffc857ae6eb7e8431d6bbe",
        "lessThan": "629666d20c7dcd740e193ec0631fdff035b1f7d6",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "793955bca66c99defdffc857ae6eb7e8431d6bbe",
        "lessThan": "4e159150a9a56d66d247f4b5510bed46fe58aa1c",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "fs/btrfs/disk-io.c",
      "fs/btrfs/extent_io.c",
      "fs/btrfs/extent_io.h"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "2.6.29"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "2.6.29",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.15.209",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.167",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.130",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.78",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.9",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "6.19",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/btrfs/disk-io.c",
      "fs/btrfs/extent_io.c",
      "fs/btrfs/extent_io.h"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-23157

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#27201 · Revision 1
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