Since commit aa563d7bca6e ("iov_iter: Separate type from direction and use accessor functions") the iov_iter_kvec and iov_iter_bvec functions warn if the direction parameter contains anything other than READ/WRITE. That commit also updated users of iov_iter_kvec/bvec but a new call was added on a different branch by commit 277e4ab7d530 ("SUNRPC: Simplify TCP receive code by switching to using iterators") This causes a flood of warnings in linux-next like this: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 110 at ../lib/iov_iter.c:1082 iov_iter_kvec+0x4c/0x5c Modules linked in: CPU: 0 PID: 110 Comm: kworker/u3:2 Tainted: G W 4.19.0-next-20181031 #157 Hardware name: Freescale i.MX6 SoloLite (Device Tree) Workqueue: xprtiod xs_stream_data_receive_workfn [<c0112908>] (unwind_backtrace) from [<c010d238>] (show_stack+0x10/0x14) [<c010d238>] (show_stack) from [<c0b3894c>] (dump_stack+0xb0/0xe8) [<c0b3894c>] (dump_stack) from [<c0126e14>] (__warn+0xe0/0x10c) [<c0126e14>] (__warn) from [<c0126f54>] (warn_slowpath_null+0x3c/0x48) [<c0126f54>] (warn_slowpath_null) from [<c04b225c>] (iov_iter_kvec+0x4c/0x5c) [<c04b225c>] (iov_iter_kvec) from [<c0a2c650>] (xs_stream_data_receive_workfn+0x538/0x8e0) [<c0a2c650>] (xs_stream_data_receive_workfn) from [<c014609c>] (process_one_work+0x2ac/0x6fc) [<c014609c>] (process_one_work) from [<c014678c>] (worker_thread+0x2a0/0x574) [<c014678c>] (worker_thread) from [<c014c43c>] (kthread+0x134/0x14c) [<c014c43c>] (kthread) from [<c01010b4>] (ret_from_fork+0x14/0x20) Exception stack(0xec9fbfb0 to 0xec9fbff8) bfa0: 00000000 00000000 00000000 00000000 bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 bfe0: 00000000 00000000 00000000 00000000 00000013 00000000 irq event stamp: 91225 hardirqs last enabled at (91233): [<c0186630>] console_unlock+0x3e4/0x5d0 hardirqs last disabled at (91250): [<c01862c8>] console_unlock+0x7c/0x5d0 softirqs last enabled at (91266): [<c0102500>] __do_softirq+0x360/0x524 softirqs last disabled at (91277): [<c012e66c>] irq_exit+0xf8/0x1a4 ---[ end trace bc12311e869d672a ]--- This fix updates sunrpc code and make nfs boot cleanly. Signed-off-by: Leonard Crestez <leonard.crestez@xxxxxxx> --- net/sunrpc/xprtsock.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) You can treat this as a bug report; I did a brief search and didn't see anyone else complain about this specific issue. Big ugly stacktrace was included so that it hopefully shows up in searches. Here is a mention of a different conflict between iov_iter and sunrpc: https://lkml.org/lkml/2018/10/29/64 diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 1b51e04d3566..ae77c71c1f64 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -359,20 +359,20 @@ xs_sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags, size_t seek) static ssize_t xs_read_kvec(struct socket *sock, struct msghdr *msg, int flags, struct kvec *kvec, size_t count, size_t seek) { - iov_iter_kvec(&msg->msg_iter, READ | ITER_KVEC, kvec, 1, count); + iov_iter_kvec(&msg->msg_iter, READ, kvec, 1, count); return xs_sock_recvmsg(sock, msg, flags, seek); } static ssize_t xs_read_bvec(struct socket *sock, struct msghdr *msg, int flags, struct bio_vec *bvec, unsigned long nr, size_t count, size_t seek) { - iov_iter_bvec(&msg->msg_iter, READ | ITER_BVEC, bvec, nr, count); + iov_iter_bvec(&msg->msg_iter, READ, bvec, nr, count); return xs_sock_recvmsg(sock, msg, flags, seek); } static ssize_t xs_read_discard(struct socket *sock, struct msghdr *msg, int flags, -- 2.17.1