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 various kinds of memory corruption. (This does not just affect "recursively oopsing" tasks; it is enough to oops once during task exit, for example in a file_operations::release handler)
How to fix
- linux linux_kernel6.1.175, 6.6.140, 6.12.88, 6.18.30, 7.0.7 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linux linux_kernel | 5.17 ≤ v < 6.1.175, 6.2 ≤ v < 6.6.140, 6.7 ≤ v < 6.12.88, 6.13 ≤ v < 6.18.30, 6.19 ≤ v < 7.0.7, 7.1 | 6.1.175, 6.6.140, 6.12.88, 6.18.30, 7.0.7 |
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