CVE-2026-46173

Description

In the Linux kernel, the following vulnerability has been resolved: exit: prevent preemption of oopsing TASK_DEAD task When an already-exiting task oopses, make_task_dead() currently calls do_task_dead() with preemption enabled. That is forbidden: do_task_dead() calls __schedule(), which has a comment saying -WARNING: must be called with preemption disabled!-. If an oopsing task is preempted in do_task_dead(), between becoming TASK_DEAD and entering the scheduler explicitly, bad things happen: finish_task_switch() assumes that once the scheduler has switched away from a TASK_DEAD task, the task can never run again and its stack is no longer needed; but that assumption apparently doesn-t hold if the dead task was preempted (the SM_PREEMPT case). This means that the scheduler ends up repeatedly dropping references on the dead task-s stack, which can lead to use-after-free or double-free of the entire task stack; in other words, two tasks can end up running on the same stack, resulting in...