io_uring: fix mshot read defer taskrun cqe posting

[ Upstream commit 70581dcd0601a09f134f23268e3374e15d736824 ]

We can't post CQEs from io-wq with DEFER_TASKRUN set, normal completions
are handled but aux should be explicitly disallowed by opcode handlers.

Cc: stable@vger.kernel.org
Fixes: fc68fcda04910 ("io_uring/rw: add support for IORING_OP_READ_MULTISHOT")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6fb7cba6f5366da25f4d3eb95273f062309d97fa.1709740837.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/io_uring/rw.c b/io_uring/rw.c
index 9394bf83e835875235d511b973ea902e4e411463..f66ace04403f7984a943b01c9cb551f07ad67290 100644 (file)
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -926,6 +926,8 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags)
         */
        if (!file_can_poll(req->file))
                return -EBADFD;
+       if (issue_flags & IO_URING_F_IOWQ)
+               return -EAGAIN;
 
        ret = __io_read(req, issue_flags);