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io_uring/poll: add hash if ready poll request can't complete inline

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If we don't, then we may lose access to it completely, leading to a
request leak. This will eventually stall the ring exit process as
well.

Cc: stable@vger.kernel.org
Fixes: 49f1c68e04 ("io_uring: optimise submission side poll_refs")
Reported-and-tested-by: syzbot+6c95df01470a47fc3af4@syzkaller.appspotmail.com
Link: https://lore.kernel.org/io-uring/0000000000009f829805f1ce87b2@google.com/
Suggested-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2023-01-09 14:46:10 -07:00
parent e6db6f9398
commit febb985c06
1 changed files with 12 additions and 5 deletions
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17
io_uring/poll.c
View file

@ -533,6 +533,14 @@ static bool io_poll_can_finish_inline(struct io_kiocb *req,
return pt->owning || io_poll_get_ownership(req);
}
static void io_poll_add_hash(struct io_kiocb *req)
{
if (req->flags & REQ_F_HASH_LOCKED)
io_poll_req_insert_locked(req);
else
io_poll_req_insert(req);
}
/*
* Returns 0 when it's handed over for polling. The caller owns the requests if
* it returns non-zero, but otherwise should not touch it. Negative values
@ -591,18 +599,17 @@ static int __io_arm_poll_handler(struct io_kiocb *req,
if (mask &&
((poll->events & (EPOLLET|EPOLLONESHOT)) == (EPOLLET|EPOLLONESHOT))) {
if (!io_poll_can_finish_inline(req, ipt))
if (!io_poll_can_finish_inline(req, ipt)) {
io_poll_add_hash(req);
return 0;
}
io_poll_remove_entries(req);
ipt->result_mask = mask;
/* no one else has access to the req, forget about the ref */
return 1;
}
if (req->flags & REQ_F_HASH_LOCKED)
io_poll_req_insert_locked(req);
else
io_poll_req_insert(req);
io_poll_add_hash(req);
if (mask && (poll->events & EPOLLET) &&
io_poll_can_finish_inline(req, ipt)) {