GHSA-3VVP-54WC-F6JR
Vulnerability from github – Published: 2026-05-08 15:31 – Updated: 2026-05-15 18:30In the Linux kernel, the following vulnerability has been resolved:
sched_ext: Fix SCX_KICK_WAIT deadlock by deferring wait to balance callback
SCX_KICK_WAIT busy-waits in kick_cpus_irq_workfn() using smp_cond_load_acquire() until the target CPU's kick_sync advances. Because the irq_work runs in hardirq context, the waiting CPU cannot reschedule and its own kick_sync never advances. If multiple CPUs form a wait cycle, all CPUs deadlock.
Replace the busy-wait in kick_cpus_irq_workfn() with resched_curr() to force the CPU through do_pick_task_scx(), which queues a balance callback to perform the wait. The balance callback drops the rq lock and enables IRQs following the sched_core_balance() pattern, so the CPU can process IPIs while waiting. The local CPU's kick_sync is advanced on entry to do_pick_task_scx() and continuously during the wait, ensuring any CPU that starts waiting for us sees the advancement and cannot form cyclic dependencies.
{
"affected": [],
"aliases": [
"CVE-2026-43326"
],
"database_specific": {
"cwe_ids": [
"CWE-667"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-05-08T14:16:42Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Fix SCX_KICK_WAIT deadlock by deferring wait to balance callback\n\nSCX_KICK_WAIT busy-waits in kick_cpus_irq_workfn() using\nsmp_cond_load_acquire() until the target CPU\u0027s kick_sync advances. Because\nthe irq_work runs in hardirq context, the waiting CPU cannot reschedule and\nits own kick_sync never advances. If multiple CPUs form a wait cycle, all\nCPUs deadlock.\n\nReplace the busy-wait in kick_cpus_irq_workfn() with resched_curr() to\nforce the CPU through do_pick_task_scx(), which queues a balance callback\nto perform the wait. The balance callback drops the rq lock and enables\nIRQs following the sched_core_balance() pattern, so the CPU can process\nIPIs while waiting. The local CPU\u0027s kick_sync is advanced on entry to\ndo_pick_task_scx() and continuously during the wait, ensuring any CPU that\nstarts waiting for us sees the advancement and cannot form cyclic\ndependencies.",
"id": "GHSA-3vvp-54wc-f6jr",
"modified": "2026-05-15T18:30:30Z",
"published": "2026-05-08T15:31:23Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43326"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/415cb193bb9736f0e830286c72a6fa8eb2a9cc5c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c3a7903f65cf4c7fb0477eb0f8b94f326a47fe54"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
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Nomenclature
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