CVE-2026-98865

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

sched ext: Don't run ops.dequeue() with a DSQ lock held

ops.dequeue() is invoked with the source user DSQ's lock still held on the consume and move paths (scx consume dispatch q(), move task between dsqs()). A BPF scheduler which locks the source user DSQ from ops.dequeue() - e.g. by iterating it with bpf iter scx dsq - self-deadlocks.

ops.dequeue() can only call the "any" kfuncs and none of them can lock a builtin DSQ, so the global and bypass paths can't deadlock; however, all DSQ locks share one lockdep class, so iterating any user DSQ from ops.dequeue() on those paths trips the recursion check.

Move the invocation after the DSQ unlock on all three paths. SCX TASK IN CUSTODY is cleared under the lock serializing the transfer so that the callback is invoked exactly once.