GHSA-2R8M-GP54-6G6C

Vulnerability from github – Published: 2026-08-10 15:33 – Updated: 2026-08-10 15:33
VLAI
Details

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

sched_ext: Preserve rq tracking across local DSQ dispatch

dispatch_to_local_dsq() can run from scx_bpf_dsq_move_to_local() while ops.dispatch() has recorded the current rq. Moving a task to a local DSQ may switch to the source or destination rq before synchronously invoking ops.dequeue() through the following path:

SCX_CALL_OP(dispatch, rq) ops.dispatch() scx_bpf_dsq_move_to_local() scx_flush_dispatch_buf() finish_dispatch() dispatch_to_local_dsq() scx_dispatch_enqueue() local_dsq_post_enq() call_task_dequeue() SCX_CALL_OP_TASK(dequeue, locked_rq, ...)

The nested callback saves the recorded rq and restores it on return. If the rq tracking does not follow the lock switch, update_locked_rq() can trigger the following lockdep assertion while restoring an rq which is no longer held:

WARNING: kernel/sched/sched.h:1641 at call_task_dequeue+0x160/0x170 Call Trace: scx_dispatch_enqueue+0x2b0/0x460 dispatch_to_local_dsq+0x138/0x230 scx_flush_dispatch_buf+0x1af/0x220 scx_bpf_dsq_move_to_localv2+0xe2/0x1c0 bpf_sched_ext_ops_dispatch+0x4b/0xa7 do_pick_task_scx+0x3b6/0x910 pick_next_task+0x105/0x1f0 __schedule+0x3e7/0x1980

Introduce switch_rq_lock() to update the tracking state together with each rq lock handoff. Use it in dispatch_to_local_dsq(), move_remote_task_to_local_dsq() and the in-balance paths of scx_dsq_move(), ensuring that scx_locked_rq() consistently refers to the rq whose lock is actually held throughout the lock dance.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-68094"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-10T13:19:53Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Preserve rq tracking across local DSQ dispatch\n\ndispatch_to_local_dsq() can run from scx_bpf_dsq_move_to_local() while\nops.dispatch() has recorded the current rq. Moving a task to a local DSQ\nmay switch to the source or destination rq before synchronously invoking\nops.dequeue() through the following path:\n\n  SCX_CALL_OP(dispatch, rq)\n    ops.dispatch()\n      scx_bpf_dsq_move_to_local()\n        scx_flush_dispatch_buf()\n          finish_dispatch()\n            dispatch_to_local_dsq()\n              scx_dispatch_enqueue()\n                local_dsq_post_enq()\n                  call_task_dequeue()\n                    SCX_CALL_OP_TASK(dequeue, locked_rq, ...)\n\nThe nested callback saves the recorded rq and restores it on return. If\nthe rq tracking does not follow the lock switch, update_locked_rq() can\ntrigger the following lockdep assertion while restoring an rq which is\nno longer held:\n\n  WARNING: kernel/sched/sched.h:1641 at call_task_dequeue+0x160/0x170\n  Call Trace:\n    scx_dispatch_enqueue+0x2b0/0x460\n    dispatch_to_local_dsq+0x138/0x230\n    scx_flush_dispatch_buf+0x1af/0x220\n    scx_bpf_dsq_move_to_local___v2+0xe2/0x1c0\n    bpf__sched_ext_ops_dispatch+0x4b/0xa7\n    do_pick_task_scx+0x3b6/0x910\n    __pick_next_task+0x105/0x1f0\n    __schedule+0x3e7/0x1980\n\nIntroduce switch_rq_lock() to update the tracking state together with\neach rq lock handoff. Use it in dispatch_to_local_dsq(),\nmove_remote_task_to_local_dsq() and the in-balance paths of\nscx_dsq_move(), ensuring that scx_locked_rq() consistently refers to the\nrq whose lock is actually held throughout the lock dance.",
  "id": "GHSA-2r8m-gp54-6g6c",
  "modified": "2026-08-10T15:33:35Z",
  "published": "2026-08-10T15:33:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68094"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/18d62044cda7a2b40f59d910659c0b0d6accad37"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/97c09c9f5739b8757ee29dabb0af30069137e286"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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