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sched/fair: Fix overflow in update_tg_cfs_runnable()

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: sched/fair: Fix overflow in update_tg_cfs_runnable() A divide-by-zero crash is observed when running hackbench: [14697.488452] CPU: 112 UID: 0 PID: 124791 Comm: hackbench Not tainted 7.1.0-rc2+ [14697.492627] RIP: 0010:propagate_entity_load_avg+0x35f/0x3e0 [14697.506799] [14697.507411] __dequeue_task+0x2b4/0xc70 [14697.508677] dequeue_task_fair+0x36/0x370 [14697.509047] dequeue_task+0x101/0x2f0 [14697.509426] __schedule+0x1b1/0x1a00 [14697.510868] anon_pipe_read+0x3da/0x450 [14697.511400] vfs_read+0x361/0x390 [14697.512053] __x64_sys_read+0x19/0x30 The divide-by-zero happens here: if (scale_load_down(gcfs_rq->load.weight)) { load_sum = div_u64(gcfs_rq->avg.load_sum, scale_load_down(gcfs_rq->load.weight)); } gcfs_rq->load.weight is an insane large value and is truncated to the lower 32 bits by div_u64, which happen to be 0. Using AI for investigation, the cause is a u32 overflow in update_tg_cfs_runnable(), and flat pickup became a victim when using tg_tasks(): u32 new_sum, divider; ... new_sum = se->avg.runnable_avg * divider; <-- boom The following sequence shows how this triggers the crash: propagate_entity_load_avg() update_tg_cfs_runnable() # u32 overflow corrupts runnable_sum __update_load_avg_cfs_rq() ___update_load_avg() # computes insane runnable_avg update_tg_load_avg() # propagates to tg->runnable_avg update_cfs_group() calc_concur_shares() tg_tasks() # long-to-int truncation, negative nr reweight_e

Announced Source revision 1
Original source ↗

CVE-2026-93182

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-2026-93182

Linux

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

Affected versions
Not stated in this record
Fixed versions
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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": "95246d1ec80b8d19d882cd8eb7ad094e63b41bb8",
        "lessThan": "39d707097a0820c6e87eff4195f0940e8ff1147e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "95246d1ec80b8d19d882cd8eb7ad094e63b41bb8",
        "lessThan": "69fafae4eb2c9fc9bcff1bcbfcccf5d197434d75",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "95246d1ec80b8d19d882cd8eb7ad094e63b41bb8",
        "lessThan": "7cc237e3bc1733928313d2462b413ae441b0eef3",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "95246d1ec80b8d19d882cd8eb7ad094e63b41bb8",
        "lessThan": "18fdd0978ec3dda0ff6865cd273e47e022180710",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "95246d1ec80b8d19d882cd8eb7ad094e63b41bb8",
        "lessThan": "f94e62d21faad5e244d0874598a4d0ebbc0ea405",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "95246d1ec80b8d19d882cd8eb7ad094e63b41bb8",
        "lessThan": "4f166adb5cb0525d9e32d45729fd8f28c80acbee",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "kernel/sched/fair.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.17"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.17",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.1.188",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.157",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.110",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.52",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.6",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "kernel/sched/fair.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-93182

Source reference: /cveMetadata/cveId

Publisher severity

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Event
#37892 · Revision 1
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