FYI, we noticed the following commit (built with gcc-7):

commit: 6a7da2a288ce412d7ac117a2912a7b0d9104ee6d ("[RFC] sunrpc: Fix flood of warnings from iov_iter_kvec in linux-next")
url: https://github.com/0day-ci/linux/commits/Leonard-Crestez/sunrpc-Fix-flood-of-warnings-from-iov_iter_kvec-in-linux-next/20181101-070713
base: git://git.linux-nfs.org/projects/trondmy/linux-nfs.git linux-next

in testcase: boot

on test machine: qemu-system-x86_64 -enable-kvm -cpu kvm64,+ssse3 -smp 2 -m 8G

caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):


+------------------------------------------------------------------------------------------+------------+------------+
|                                                                                          | 86bbd7422a | 6a7da2a288 |
+------------------------------------------------------------------------------------------+------------+------------+
| boot_successes                                                                           | 8          | 0          |
| boot_failures                                                                            | 6          | 35         |
| Kernel_panic-not_syncing:initrd_too_large_to_handle,disabling_initrd(#needed,#available) | 6          | 4          |
| kernel_BUG_at_lib/iov_iter.c                                                             | 0          | 31         |
| invalid_opcode:#[##]                                                                     | 0          | 31         |
| RIP:iov_iter_kvec                                                                        | 0          | 31         |
| Kernel_panic-not_syncing:Fatal_exception                                                 | 0          | 31         |
+------------------------------------------------------------------------------------------+------------+------------+



[  103.400523] kernel BUG at lib/iov_iter.c:1067!
[  103.415315] invalid opcode: 0000 [#1] SMP PTI
[  103.425743] CPU: 0 PID: 358 Comm: kworker/u5:1 Not tainted 4.19.0-rc6-00095-g6a7da2a #1
[  103.444219] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[  103.464595] Workqueue: xprtiod xs_stream_data_receive_workfn
[  103.477431] RIP: 0010:iov_iter_kvec+0x1d/0x20
[  103.487834] Code: 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 40 f6 c6 02 74 17 89 37 48 89 57 18 48 89 4f 20 48 c7 47 08 00 00 00 00 4c 89 47 10 c3 <0f> 0b 90 40 f6 c6 04 74 17 89 37 48 89 57 18 48 89 4f 20 48 c7 47
[  103.529675] RSP: 0000:ffffb760411a7dd0 EFLAGS: 00010246
[  103.541990] RAX: ffff8902d4405d20 RBX: ffffb760411a7e00 RCX: 0000000000000001
[  103.559385] RDX: ffffb760411a7df0 RSI: 0000000000000000 RDI: ffffb760411a7e10
[  103.576569] RBP: 0000000000000000 R08: 000000000000000c R09: 8080808080808080
[  103.593182] R10: 0000000000000000 R11: fefefefefefefeff R12: ffff8902d4405800
[  103.609806] R13: ffff8902d8538c00 R14: 0000000000000000 R15: 000000000000000c
[  103.626499] FS:  0000000000000000(0000) GS:ffff89033fc00000(0000) knlGS:0000000000000000
[  103.645847] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  103.658781] CR2: 00005574746cf808 CR3: 00000001d8952000 CR4: 00000000000006f0
[  103.674923] Call Trace:
[  103.681009]  xs_stream_data_receive+0xbb/0x4d0
[  103.691127]  ? __switch_to_asm+0x34/0x70
[  103.700388]  process_one_work+0x196/0x3a0
[  103.710075]  worker_thread+0x3c/0x3a0
[  103.718542]  ? process_one_work+0x3a0/0x3a0
[  103.727843]  kthread+0x11e/0x140
[  103.735419]  ? kthread_create_worker_on_cpu+0x70/0x70
[  103.747120]  ret_from_fork+0x35/0x40
[  103.755907] Modules linked in: ppdev snd_pcm bochs_drm snd_timer ttm drm_kms_helper snd soundcore virtio_pci joydev drm virtio_ring pcspkr serio_raw virtio i6300esb ata_generic i2c_piix4 pata_acpi parport_pc parport floppy qemu_fw_cfg
[  103.803280] ---[ end trace b47e3b48d3a08066 ]---


To reproduce:

        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email



Thanks,
lkp