io_uring: drop mm/files between task_work_submit

[ Upstream commit aec18a57edad562d620f7d19016de1fc0cc2208c ]

Since SQPOLL task can be shared and so task_work entries can be a mix of
them, we need to drop mm and files before trying to issue next request.

Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index fca3a6c..d0b7332 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2084,6 +2084,9 @@ static void __io_req_task_submit(struct io_kiocb *req)
        else
                __io_req_task_cancel(req, -EFAULT);
        mutex_unlock(&ctx->uring_lock);
+
+       if (ctx->flags & IORING_SETUP_SQPOLL)
+               io_sq_thread_drop_mm();
 }
 
 static void io_req_task_submit(struct callback_head *cb)