Unspecified impact via deferred dispatch-queue use-after-free

Use-after-free in Linux 7.1 sched_ext allows attackers to cause unspecified impact via deferred dispatch-queue reenqueue requests. In kernel/sched/ext/ext.c, exit_dsq() assumes an RCU grace period drains pending requests, but run_deferred() can detach a request after that period begins and read a freed queue's ID. Exposure requires a running sched_ext BPF scheduler and overlapping user-queue destruction and deferred reenqueue processing; attacker privileges and consequences beyond the invalid kernel read are undocumented.