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authorPavel Begunkov <asml.silence@gmail.com>2022-11-18 15:41:41 +0000
committerJens Axboe <axboe@kernel.dk>2022-11-18 09:29:31 -0700
commit7fdbc5f014c3f71bc44673a2d6c5bb2d12d45f25 (patch)
treeee0554114e62170dd45f607cf99fc5a7c7dfedcb /io_uring/poll.c
parent100d6b17c06ee4c2b42fdddf0fe4ab77c86eb77e (diff)
io_uring: disallow self-propelled ring polling
When we post a CQE we wake all ring pollers as it normally should be. However, if a CQE was generated by a multishot poll request targeting its own ring, it'll wake that request up, which will make it to post a new CQE, which will wake the request and so on until it exhausts all CQ entries. Don't allow multishot polling io_uring files but downgrade them to oneshots, which was always stated as a correct behaviour that the userspace should check for. Cc: stable@vger.kernel.org Fixes: aa43477b04025 ("io_uring: poll rework") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/3124038c0e7474d427538c2d915335ec28c92d21.1668785722.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring/poll.c')
-rw-r--r--io_uring/poll.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/io_uring/poll.c b/io_uring/poll.c
index c34019b18211..055632e9092a 100644
--- a/io_uring/poll.c
+++ b/io_uring/poll.c
@@ -246,6 +246,8 @@ static int io_poll_check_events(struct io_kiocb *req, bool *locked)
continue;
if (req->apoll_events & EPOLLONESHOT)
return IOU_POLL_DONE;
+ if (io_is_uring_fops(req->file))
+ return IOU_POLL_DONE;
/* multishot, just fill a CQE and proceed */
if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {