GHSA-4GJP-M56Q-X3CM

Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-22 18:30
VLAI
Details

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

samples/damon/mtier: error out for zero quota goal target values

Patch series "mm/damon: avoid division by zero from damos_quota_score()".

DAMON_SAMPLE_MTIER and DAMON_LRU_SORT allow the user to trigger division by zero in damos_quota_score(). Avoid it by adding parameters validation checks.

This patch (of 2):

damos_quota_score() can trigger division by zero if the target_value is zero. DAMON_SAMPLE_MTIER lets users set the target_value via node0_mem_{used,free}bp parameters. It doesn't guard zero value case, though. As a result, users can trigger division by zero. Fix the issue by returning an error when the user tries to start DAMON with zero node0_mem{used,free}_bp parameter values.

DAMON_SAMPLE_MTIER is just a sample module, but the consequence is quite bad. Also the zero node0_mem_free_bp parameter might look like a reasonable setup to some users. Hence, the issue might really happen in the real world.

One reliable way to reproduce the issue is like below:

# cd /sys/module/damon_sample_mtier/parameters
# echo 4096 > node0_start_addr
# echo 8192 > node0_end_addr
# echo 8192 > node1_start_addr
# echo 81920 > node1_end_addr
# echo 0 > node0_mem_free_bp
# echo Y > enabled
# dmesg -w
[...]
[18792.235916] Oops: divide error: 0000 [#1] SMP NOPTI
[...]
[18792.242787] RIP: 0010:damos_quota_score+0x6f/0x480
[...]

This issue was discovered [1] by Sashiko.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-74643"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-22T16:16:37Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsamples/damon/mtier: error out for zero quota goal target values\n\nPatch series \"mm/damon: avoid division by zero from damos_quota_score()\".\n\nDAMON_SAMPLE_MTIER and DAMON_LRU_SORT allow the user to trigger division\nby zero in damos_quota_score().  Avoid it by adding parameters validation\nchecks.\n\n\nThis patch (of 2):\n\ndamos_quota_score() can trigger division by zero if the target_value is\nzero.  DAMON_SAMPLE_MTIER lets users set the target_value via\nnode0_mem_{used,free}_bp parameters.  It doesn\u0027t guard zero value case,\nthough.  As a result, users can trigger division by zero.  Fix the issue\nby returning an error when the user tries to start DAMON with zero\nnode0_mem_{used,free}_bp parameter values.\n\nDAMON_SAMPLE_MTIER is just a sample module, but the consequence is quite\nbad.  Also the zero node0_mem_free_bp parameter might look like a\nreasonable setup to some users.  Hence, the issue might really happen in\nthe real world.\n\nOne reliable way to reproduce the issue is like below:\n\n    # cd /sys/module/damon_sample_mtier/parameters\n    # echo 4096 \u003e node0_start_addr\n    # echo 8192 \u003e node0_end_addr\n    # echo 8192 \u003e node1_start_addr\n    # echo 81920 \u003e node1_end_addr\n    # echo 0 \u003e node0_mem_free_bp\n    # echo Y \u003e enabled\n    # dmesg -w\n    [...]\n    [18792.235916] Oops: divide error: 0000 [#1] SMP NOPTI\n    [...]\n    [18792.242787] RIP: 0010:damos_quota_score+0x6f/0x480\n    [...]\n\nThis issue was discovered [1] by Sashiko.",
  "id": "GHSA-4gjp-m56q-x3cm",
  "modified": "2026-08-22T18:30:27Z",
  "published": "2026-08-22T18:30:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74643"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/684f271210becd7b8c4088f06c442499e48a43a0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a16fd3ad9d89b05475864da97327870464611736"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e16b8d640ec99b28bc827560edcf9706e610c3aa"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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