Merge tag 'sched_ext-for-6.14-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext

Pull sched_ext fix from Tejun Heo:
 "BPF schedulers could trigger a crash by passing in an invalid CPU to
  the scx_bpf_select_cpu_dfl() helper.

  Fix it by verifying input validity"

* tag 'sched_ext-for-6.14-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
  sched_ext: Validate prev_cpu in scx_bpf_select_cpu_dfl()

Author: torvalds

kernel/sched/ext.c

@@ -6422,6 +6422,9 @@ static bool check_builtin_idle_enabled(void)
 __bpf_kfunc s32 scx_bpf_select_cpu_dfl(struct task_struct *p, s32 prev_cpu,
 				       u64 wake_flags, bool *is_idle)
 {
+	if (!ops_cpu_valid(prev_cpu, NULL))
+		goto prev_cpu;
+
 	if (!check_builtin_idle_enabled())
 		goto prev_cpu;