From: Jens Axboe axboe@kernel.dk
commit 5d204bcfa09330972ad3428a8f81c23f371d3e6d upstream.
If we have a read/write that is deferred, we already setup the async IO context for that request, and mapped it. When we later try and execute the request and we get -EAGAIN, we don't want to attempt to re-map it. If we do, we end up with garbage in the iovec, which typically leads to an -EFAULT or -EINVAL completion.
Cc: stable@vger.kernel.org # 5.5 Reported-by: Dan Melnic dmm@fb.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/io_uring.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
--- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1789,10 +1789,12 @@ static int io_setup_async_rw(struct io_k if (req->opcode == IORING_OP_READ_FIXED || req->opcode == IORING_OP_WRITE_FIXED) return 0; - if (!req->io && io_alloc_async_ctx(req)) - return -ENOMEM; + if (!req->io) { + if (io_alloc_async_ctx(req)) + return -ENOMEM;
- io_req_map_rw(req, io_size, iovec, fast_iov, iter); + io_req_map_rw(req, io_size, iovec, fast_iov, iter); + } req->work.func = io_rw_async; return 0; }