On 10/14/24 5:48 AM, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > > The patch below does not apply to the 6.11-stable tree. > If someone wants it applied there, or to any other stable or longterm > tree, then please email the backport, including the original git commit > id to <stable@xxxxxxxxxxxxxxx>. > > To reproduce the conflict and resubmit, you may use the following commands: > > git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.11.y > git checkout FETCH_HEAD > git cherry-pick -x c9d952b9103b600ddafc5d1c0e2f2dbd30f0b805 > # <resolve conflicts, build, test, etc.> > git commit -s > git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2024101436-avalanche-approach-5c90@gregkh' --subject-prefix 'PATCH 6.11.y' HEAD^.. Here's the tested backport of that patch. -- Jens Axboe
From c5bada95115a2515fdc30d8675db628cfa31e4b7 Mon Sep 17 00:00:00 2001 From: Jens Axboe <axboe@xxxxxxxxx> Date: Sat, 5 Oct 2024 19:06:50 -0600 Subject: [PATCH] io_uring/rw: fix cflags posting for single issue multishot read Commit c9d952b9103b600ddafc5d1c0e2f2dbd30f0b805 upstream. If multishot gets disabled, and hence the request will get terminated rather than persist for more iterations, then posting the CQE with the right cflags is still important. Most notably, the buffer reference needs to be included. Refactor the return of __io_read() a bit, so that the provided buffer is always put correctly, and hence returned to the application. Reported-by: Sharon Rosner <Sharon Rosner> Link: https://github.com/axboe/liburing/issues/1257 Cc: stable@xxxxxxxxxxxxxxx Fixes: 2a975d426c82 ("io_uring/rw: don't allow multishot reads without NOWAIT support") Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> --- io_uring/rw.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) diff --git a/io_uring/rw.c b/io_uring/rw.c index 56a69f0e5d23..2185a132e7f5 100644 --- a/io_uring/rw.c +++ b/io_uring/rw.c @@ -972,17 +972,21 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags) if (issue_flags & IO_URING_F_MULTISHOT) return IOU_ISSUE_SKIP_COMPLETE; return -EAGAIN; - } - - /* - * Any successful return value will keep the multishot read armed. - */ - if (ret > 0 && req->flags & REQ_F_APOLL_MULTISHOT) { + } else if (ret <= 0) { + io_kbuf_recycle(req, issue_flags); + if (ret < 0) + req_set_fail(req); + } else { /* - * Put our buffer and post a CQE. If we fail to post a CQE, then + * Any successful return value will keep the multishot read + * armed, if it's still set. Put our buffer and post a CQE. If + * we fail to post a CQE, or multishot is no longer set, then * jump to the termination path. This request is then done. */ cflags = io_put_kbuf(req, issue_flags); + if (!(req->flags & REQ_F_APOLL_MULTISHOT)) + goto done; + rw->len = 0; /* similarly to above, reset len to 0 */ if (io_req_post_cqe(req, ret, cflags | IORING_CQE_F_MORE)) { @@ -1003,6 +1007,7 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags) * Either an error, or we've hit overflow posting the CQE. For any * multishot request, hitting overflow will terminate it. */ +done: io_req_set_res(req, ret, cflags); io_req_rw_cleanup(req, issue_flags); if (issue_flags & IO_URING_F_MULTISHOT) -- 2.45.2
