On 1/15/25 01:50, lizetao wrote:
Hi,
-----Original Message-----
From: Pavel Begunkov <asml.silence@xxxxxxxxx>
Sent: Wednesday, January 15, 2025 12:22 AM
To: lizetao <lizetao1@xxxxxxxxxx>; Jens Axboe <axboe@xxxxxxxxx>
Cc: io-uring@xxxxxxxxxxxxxxx
Subject: Re: [PATCH] io_uring/io-wq: Fix a small time window for reading work-
flags
On 1/14/25 02:06, lizetao wrote:
There is a small time window that is modified by other tasks after
reading work->flags. It is changed to read before use, which is more
Can you elaborate on what races with what? I don't immediately see any race
here.
There is such a race context:
worker process
io_worker_handle_work: IORING_OP_ASYNC_CANCEL
io_wq_enqueue __io_wq_worker_cancel
work_flags = atomic_read(&work->flags); // no IO_WQ_WORK_CANCEL
atomic_or(IO_WQ_WORK_CANCEL, &work->flags);
^^^
That can't happen, the request is not discoverable via iowq yet.
if (work_flags & IO_WQ_WORK_CANCEL) // false
This check is for requests that came with the flag already set.
--
Pavel Begunkov
