From: Jens Axboe Date: Fri, 31 Jan 2020 19:06:52 +0000 (-0700) Subject: io_uring: don't map read/write iovec potentially twice X-Git-Tag: v5.5.3~146 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=f9ce114dfbc4d70d09742b5039487e07402cbd8d;p=users%2Fdwmw2%2Flinux.git io_uring: don't map read/write iovec potentially twice 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 Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/io_uring.c b/fs/io_uring.c index e54556b0fcc69..c96d0c361ff0d 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1789,10 +1789,12 @@ static int io_setup_async_rw(struct io_kiocb *req, ssize_t io_size, 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; }