Warning reported in syslog on boot with google n2d instances

[Po-Hsu Lin]

Issue found on 5.4.0-1072.77~18.04.1
With instance n2d-standard-2 / n2d-standard-64 only.

log_check test in ubuntu_boot suite report warning found in syslog.

 kernel: [ 154.683117] WARNING: CPU: 0 PID: 15451 at /build/linux-gcp-5.4-NNZpX1/linux-gcp-5.4-5.4.0/kernel/dma/direct.c:35 report_addr+0x33/0x90

Complete trace:
 ------------[ cut here ]------------
 WARNING: CPU: 10 PID: 465 at /build/linux-gcp-5.4-UX3Oaq/linux-gcp-5.4-5.4.0/kernel/dma/direct.c:35 report_addr+0x33/0x90
 Modules linked in: ip6table_filter ip6_tables iptable_filter bpfilter nls_iso8859_1 pvpanic input_leds serio_raw mac_hid sch_fq_codel ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ip_tables x_tables autofs4 btrfs zstd_compress raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq raid1 raid0 multipath linear crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel crypto_simd cryptd glue_helper psmouse gve i2c_piix4
 CPU: 10 PID: 465 Comm: kworker/u129:1 Not tainted 5.4.0-1072-gcp #77~18.04.1-Ubuntu
 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 Workqueue: writeback wb_workfn (flush-259:0)
 RIP: 0010:report_addr+0x33/0x90
 Code: 48 83 ec 08 48 8b 87 30 02 00 00 48 89 75 f8 48 85 c0 74 26 4c 8b 00 b8 fe ff ff ff 49 39 c0 76 0d 80 3d c7 66 b2 01 00 74 2e <0f> 0b c9 c3 48 83 bf 40 02 00 00 00 75 e9 eb f0 80 3d af 66 b2 01
 RSP: 0018:ffffad2c4d90b510 EFLAGS: 00010282
 RAX: 0000000000000000 RBX: ffff8d373837b0b0 RCX: 0000000000000000
 RDX: 0000000000000000 RSI: ffff8d373f69c448 RDI: 0000000000000000
 RBP: ffffad2c4d90b518 R08: 0000000000000309 R09: 000000000000000a
 R10: 000000000016dfee R11: ffffad2c4d90b248 R12: 0000000000040000
 R13: ffff8d36f00fe000 R14: 0000000000000001 R15: 0000000000000100
 FS: 0000000000000000(0000) GS:ffff8d373f680000(0000) knlGS:0000000000000000
 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 000056455033c988 CR3: 0000802788a0a000 CR4: 0000000000340ee0
 Call Trace:
  dma_direct_map_page+0xe2/0xf0
  dma_direct_map_sg+0x6c/0xc0
  nvme_queue_rq+0x6fb/0xbd0
  __blk_mq_try_issue_directly+0x139/0x200
  ? mempool_alloc+0x1/0x190
  blk_mq_request_issue_directly+0x4b/0xe0
  blk_mq_try_issue_list_directly+0x46/0xb0
  blk_mq_sched_insert_requests+0xb7/0x100
  blk_mq_flush_plug_list+0x1eb/0x2a0
  blk_flush_plug_list+0xd1/0x100
  blk_mq_make_request+0x306/0x5a0
  generic_make_request+0x121/0x300
  ? jbd2_journal_stop+0xf6/0x3e0
  submit_bio+0x46/0x1c0
  ? submit_bio+0x46/0x1c0
  ext4_io_submit+0x4d/0x60
  ext4_writepages+0x624/0xe80
  do_writepages+0x4b/0xe0
  ? do_writepages+0x4b/0xe0
  ? blk_mq_request_issue_directly+0x4b/0xe0
  __writeback_single_inode+0x40/0x310
  ? __writeback_single_inode+0x40/0x310
  writeback_sb_inodes+0x1dc/0x530
  __writeback_inodes_wb+0x67/0xb0
  wb_writeback+0x260/0x2f0
  wb_workfn+0x196/0x4c0
  ? wb_workfn+0x196/0x4c0
  ? __switch_to_asm+0x40/0x70
  ? __switch_to_asm+0x40/0x70
  ? __switch_to_asm+0x34/0x70
  ? __switch_to_asm+0x40/0x70
  ? __switch_to_asm+0x34/0x70
  ? __switch_to_asm+0x40/0x70
  process_one_work+0x20f/0x400
  ? process_one_work+0x20f/0x400
  worker_thread+0x34/0x410
  kthread+0x121/0x140
  ? process_one_work+0x400/0x400
  ? kthread_park+0x90/0x90
  ret_from_fork+0x22/0x40
 ---[ end trace f4e72354e0533b13 ]---

In Focal 5.4 generic kernel, this section that trigger the warning message is:
static void report_addr(struct device *dev, dma_addr_t dma_addr, size_t size)
{
    if (!dev->dma_mask) {
        dev_err_once(dev, "DMA map on device without dma_mask\n");
    } else if (*dev->dma_mask >= DMA_BIT_MASK(32) || dev->bus_dma_mask) {
        dev_err_once(dev,
            "overflow %pad+%zu of DMA mask %llx bus mask %llx\n",
            &dma_addr, size, *dev->dma_mask, dev->bus_dma_mask);
    }
    WARN_ON_ONCE(1);
}

[Po-Hsu Lin (cypressyew)]

Note that this issue does not exist with Focal GCP 5.4.0-1072.77