Commit c0737fa9 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: fix double poll leak on repolling 



We have re-polling for partial IO, so a request can be polled twice. If
it used two poll entries the first time then on the second
io_arm_poll_handler() it will find the old apoll entry and NULL
kmalloc()'ed second entry, i.e. apoll->double_poll, so leaking it.

Fixes: 10c87333 ("io_uring: allow re-poll if we made progress")
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/fee2452494222ecc7f1f88c8fb659baef971414a.1655852245.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 9d2ad294

fs/io_uring.c

+1 −0
Original line number Diff line number Diff line
@@ -7208,6 +7208,7 @@ static int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags) 
		mask |= EPOLLEXCLUSIVE;

	if (req->flags & REQ_F_POLLED) {

		apoll = req->apoll;

		kfree(apoll->double_poll);

	} else if (!(issue_flags & IO_URING_F_UNLOCKED) &&

		   !list_empty(&ctx->apoll_cache)) {

		apoll = list_first_entry(&ctx->apoll_cache, struct async_poll,