CVE-2026-31734

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> sched_ext: Fix is_bpf_migration_disabled() false negative on non-PREEMPT_RCU<br /> <br /> Since commit 8e4f0b1ebcf2 ("bpf: use rcu_read_lock_dont_migrate() for<br /> trampoline.c"), the BPF prolog (__bpf_prog_enter) calls migrate_disable()<br /> only when CONFIG_PREEMPT_RCU is enabled, via rcu_read_lock_dont_migrate().<br /> Without CONFIG_PREEMPT_RCU, the prolog never touches migration_disabled,<br /> so migration_disabled == 1 always means the task is truly<br /> migration-disabled regardless of whether it is the current task.<br /> <br /> The old unconditional p == current check was a false negative in this<br /> case, potentially allowing a migration-disabled task to be dispatched to<br /> a remote CPU and triggering scx_error in task_can_run_on_remote_rq().<br /> <br /> Only apply the p == current disambiguation when CONFIG_PREEMPT_RCU is<br /> enabled, where the ambiguity with the BPF prolog still exists.