From 797f3f535d59f05ad12c629338beef6cb801d19e Mon Sep 17 00:00:00 2001 From: Bijan Mottahedeh Date: Wed, 15 Jan 2020 18:37:45 -0800 Subject: [PATCH] io_uring: clear req->result always before issuing a read/write request req->result is cleared when io_issue_sqe() calls io_read/write_pre() routines. Those routines however are not called when the sqe argument is NULL, which is the case when io_issue_sqe() is called from io_wq_submit_work(). io_issue_sqe() may then examine a stale result if a polled request had previously failed with -EAGAIN: if (ctx->flags & IORING_SETUP_IOPOLL) { if (req->result == -EAGAIN) return -EAGAIN; io_iopoll_req_issued(req); } and in turn cause a subsequently completed request to be re-issued in io_wq_submit_work(). Signed-off-by: Bijan Mottahedeh Signed-off-by: Jens Axboe --- fs/io_uring.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index e32268ce38a5..3130ed16456e 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1843,6 +1843,7 @@ static int io_read(struct io_kiocb *req, struct io_kiocb **nxt, if (!force_nonblock) req->rw.kiocb.ki_flags &= ~IOCB_NOWAIT; + req->result = 0; io_size = ret; if (req->flags & REQ_F_LINK) req->result = io_size; @@ -1930,6 +1931,7 @@ static int io_write(struct io_kiocb *req, struct io_kiocb **nxt, if (!force_nonblock) req->rw.kiocb.ki_flags &= ~IOCB_NOWAIT; + req->result = 0; io_size = ret; if (req->flags & REQ_F_LINK) req->result = io_size;