CVE-2026-89518

CVE CVE-2026-89518EUVD EUVD-2026-76424Published 2026-09-11T19:44:01.000Z

What the advisory describes

In the Linux kernel, the following vulnerability has been resolved: sched_ext: Fix this_rq() assumptions in dispatch kfuncs Under core scheduling, dispatch runs from within the core-wide pick and can target a sibling rq, so ops.dispatch() may execute on a CPU different from the dispatched rq's. Several kfunc paths assumed the two always coincide: - scx_dsq_move() decided whether an rq lock is held by testing this_rq()'s rq flags and lock-danced accordingly. A dispatch for a sibling took the unlocked-context branch and acquired the source rq lock on top of the already held dispatched rq lock which could deadlock. - scx_bpf_sub_dispatch() dispatched this_rq() with its stashed sub_dispatch_prev, which is NULL when dispatching for a sibling. - finish_dispatch(), scx_bpf_dsq_reenq() and scx_bpf_dsq_nr_queued() resolved SCX_DSQ_LOCAL to this CPU's local DSQ rather than the dispatched rq's. The latter two are callable from other rq-locked operations too, where SCX_DSQ_LOCAL now likewise resolves to the op's rq. This changes behavior also without core scheduling, e.g. for ops.enqueue() running a remote wakeup on the waking CPU, and is intended: which CPU happens to execute an operation is incidental, the op's rq is what it is operating on, and the resolution now matches the insert side where SCX_DSQ_LOCAL dispatches land on the task's rq. Use the rq tracked by scx_locked_rq(), which is set to the dispatched rq around ops invocations and NULL in unlocked contexts.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

• Linux — Linux 6.19; 4c95380701f58b8112f0b891de8d160e4199e19d <3dd52416e44a70bc993adb96d2e0d71b9ea21359; patch: 7.2.4; 4c95380701f58b8112f0b891de8d160e4199e19d <6d1890d3c6137ab523799765ae2de62cc05f116d; patch: 7.3-rc1; patch: 0

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

• Linux — Linux

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