io_uring：修复共享 sqpoll 取消挂起 (CVE-2021-46942)
CVE编号
CVE-2021-46942利用情况
暂无补丁情况
N/A披露时间
2024-02-28漏洞描述
In the Linux kernel, the following vulnerability has been resolved: io_uring: fix shared sqpoll cancellation hangs [ 736.982891] INFO: task iou-sqp-4294:4295 blocked for more than 122 seconds. [ 736.982897] Call Trace: [ 736.982901] schedule+0x68/0xe0 [ 736.982903] io_uring_cancel_sqpoll+0xdb/0x110 [ 736.982908] io_sqpoll_cancel_cb+0x24/0x30 [ 736.982911] io_run_task_work_head+0x28/0x50 [ 736.982913] io_sq_thread+0x4e3/0x720 We call io_uring_cancel_sqpoll() one by one for each ctx either in sq_thread() itself or via task works, and it's intended to cancel all requests of a specified context. However the function uses per-task counters to track the number of inflight requests, so it counts more requests than available via currect io_uring ctx and goes to sleep for them to appear (e.g. from IRQ), that will never happen. Cancel a bit more than before, i.e. all ctxs that share sqpoll and continue to use shared counters. Don't forget that we should not remove ctx from the list before running that task_work sqpoll-cancel, otherwise the function wouldn't be able to find the context and will hang.解决建议
建议您更新当前系统或软件至最新版，完成漏洞的修复。
参考链接 |
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| https://git.kernel.org/stable/c/734551df6f9bedfbefcd113ede665945e9de0b99 | |
| https://git.kernel.org/stable/c/cb5e0b3d0f993a6268c1a2c7ede2f9aa0c17ef68 |
- 攻击路径 N/A
- 攻击复杂度 N/A
- 权限要求 N/A
- 影响范围 N/A
- 用户交互 N/A
- 可用性 N/A
- 保密性 N/A
- 完整性 N/A
| CWE-ID | 漏洞类型 |
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