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| author | Pavel Begunkov <asml.silence@gmail.com> | 2022-11-18 15:41:41 +0000 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2022-11-18 09:29:31 -0700 |
| commit | 7fdbc5f014c3f71bc44673a2d6c5bb2d12d45f25 (patch) | |
| tree | ee0554114e62170dd45f607cf99fc5a7c7dfedcb /io_uring | |
| parent | 100d6b17c06ee4c2b42fdddf0fe4ab77c86eb77e (diff) | |
| download | linux-7fdbc5f014c3f71bc44673a2d6c5bb2d12d45f25.tar.bz2 | |
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')
| -rw-r--r-- | io_uring/poll.c | 2 |
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)) { |