CVE-2021-47569

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> io_uring: fail cancellation for EXITING tasks<br /> <br /> WARNING: CPU: 1 PID: 20 at fs/io_uring.c:6269 io_try_cancel_userdata+0x3c5/0x640 fs/io_uring.c:6269<br /> CPU: 1 PID: 20 Comm: kworker/1:0 Not tainted 5.16.0-rc1-syzkaller #0<br /> Workqueue: events io_fallback_req_func<br /> RIP: 0010:io_try_cancel_userdata+0x3c5/0x640 fs/io_uring.c:6269<br /> Call Trace:<br /> <br /> io_req_task_link_timeout+0x6b/0x1e0 fs/io_uring.c:6886<br /> io_fallback_req_func+0xf9/0x1ae fs/io_uring.c:1334<br /> process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298<br /> worker_thread+0x658/0x11f0 kernel/workqueue.c:2445<br /> kthread+0x405/0x4f0 kernel/kthread.c:327<br /> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295<br /> <br /> <br /> We need original task&amp;#39;s context to do cancellations, so if it&amp;#39;s dying<br /> and the callback is executed in a fallback mode, fail the cancellation<br /> attempt.