CVE-2021-47569
Description
In the Linux kernel, the following vulnerability has been resolved: io_uring: fail cancellation for EXITING tasks WARNING: CPU: 1 PID: 20 at fs/io_uring.c:6269 io_try_cancel_userdata+0x3c5/0x640 fs/io_uring.c:6269 CPU: 1 PID: 20 Comm: kworker/1:0 Not tainted 5.16.0-rc1-syzkaller #0 Workqueue: events io_fallback_req_func RIP: 0010:io_try_cancel_userdata+0x3c5/0x640 fs/io_uring.c:6269 Call Trace: <TASK> io_req_task_link_timeout+0x6b/0x1e0 fs/io_uring.c:6886 io_fallback_req_func+0xf9/0x1ae fs/io_uring.c:1334 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 </TASK> We need original task's context to do cancellations, so if it's dying and the callback is executed in a fallback mode, fail the cancellation attempt.
How to fix
- linux linux_kernel5.15.6 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linux linux_kernel | 5.15 ≤ v < 5.15.6, 5.16 | 5.15.6 |
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