io_uring/net: fix cleanup double free free_iov init
Having ->async_data doesn't mean it's initialised and previously we vere relying on setting F_CLEANUP at the right moment. With zc sendmsg though, we set F_CLEANUP early in prep when we alloc a notif and so we may allocate async_data, fail in copy_msg_hdr() leaving struct io_async_msghdr not initialised correctly but with F_CLEANUP set, which causes a ->free_iov double free and probably other nastiness. Always initialise ->free_iov. Also, now it might point to fast_iov when fails, so avoid freeing it during cleanups. Reported-by: syzbot+edfd15cd4246a3fc615a@syzkaller.appspotmail.com Fixes: 493108d9 ("io_uring/net: zerocopy sendmsg") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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