vmw_pvscsi 0000:13:00.0: DMA-API: device driver failed to check map error[device address=0x0000000028cbcc40]

[Reindl H. <h.r...@th...>]

may somebody of VMware Inc. please take a look at
https://bugzilla.redhat.com/show_bug.cgi?id=926917

these messages appear in dmesg in case of debug-kernels for a long time
and given that we speak about the main storage driver that leaves a
bad taste

[   15.641689] scsi2 : VMware PVSCSI storage adapter rev 2, req/cmp/msg rings: 8/8/1 pages, cmd_per_lun=64
[   15.650348] vmw_pvscsi 0000:13:00.0: VMware PVSCSI rev 2 host #2
[   15.656531] ------------[ cut here ]------------
[   15.657055] WARNING: CPU: 0 PID: 6 at lib/dma-debug.c:937 check_unmap+0x47b/0x920()
[   15.657577] vmw_pvscsi 0000:13:00.0: DMA-API: device driver failed to check map error[device
address=0x0000000028cbcc40] [size=96 bytes] [mapped as single]
[   15.658483] Modules linked in:
[   15.659064]  vmw_pvscsi(+)
[   15.659460] CPU: 0 PID: 6 Comm: kworker/u2:0 Not tainted 3.14.0-0.rc0.git3.1.fc21.x86_64 #1
[   15.660174] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00
07/31/2013
[   15.661267] Workqueue: events_unbound async_run_entry_fn
[   15.661944]  0000000000000009 ffff88002fc03ad8 ffffffff817685b8 ffff88002fc03b20
[   15.662548]  ffff88002fc03b10 ffffffff8107ad3d ffff88002d24f2d0 ffff88002c51ee38
[   15.663353]  ffffffff82d6b950 0000000000000086 ffffffff81a23e5b ffff88002fc03b70
[   15.664135] Call Trace:
[   15.664481]  <IRQ>  [<ffffffff817685b8>] dump_stack+0x4d/0x66
[   15.665162]  [<ffffffff8107ad3d>] warn_slowpath_common+0x7d/0xa0
[   15.665626]  [<ffffffff8107adac>] warn_slowpath_fmt+0x4c/0x50
[   15.666272]  [<ffffffff813b523b>] check_unmap+0x47b/0x920
[   15.666941]  [<ffffffff813b582d>] ? debug_dma_unmap_sg+0x6d/0x130
[   15.667574]  [<ffffffff813b573f>] debug_dma_unmap_page+0x5f/0x70
[   15.668141]  [<ffffffffa00006ba>] pvscsi_unmap_buffers.isra.12+0x11a/0x1f0 [vmw_pvscsi]
[   15.668912]  [<ffffffffa0000896>] pvscsi_process_completion_ring+0x106/0x2d0 [vmw_pvscsi]
[   15.669496]  [<ffffffffa0000b14>] pvscsi_isr+0x34/0xa0 [vmw_pvscsi]
[   15.670171]  [<ffffffff810ed3fe>] handle_irq_event_percpu+0x3e/0x370
[   15.670661]  [<ffffffff810ed76d>] handle_irq_event+0x3d/0x60
[   15.671305]  [<ffffffff810f0257>] handle_edge_irq+0x77/0x130
[   15.671935]  [<ffffffff8101bbaf>] handle_irq+0xbf/0x150
[   15.672385]  [<ffffffff81081aa2>] ? irq_enter+0x42/0x90
[   15.673000]  [<ffffffff8177d34f>] do_IRQ+0x4f/0xf0
[   15.673521]  [<ffffffff81771eb2>] common_interrupt+0x72/0x72
[   15.674089]  [<ffffffff810814e8>] ? __do_softirq+0xc8/0x460
[   15.674557]  [<ffffffff810814e1>] ? __do_softirq+0xc1/0x460
[   15.675196]  [<ffffffff810bd8d1>] ? sched_clock_cpu+0x11/0xd0
[   15.675670]  [<ffffffff81081bb5>] irq_exit+0xc5/0xd0
[   15.676285]  [<ffffffff8177d435>] smp_apic_timer_interrupt+0x45/0x60
[   15.676927]  [<ffffffff8177bd72>] apic_timer_interrupt+0x72/0x80
[   15.677410]  <EOI>  [<ffffffff8177119b>] ? _raw_spin_unlock_irqrestore+0x3b/0x70
[   15.678148]  [<ffffffffa0001750>] pvscsi_queue+0x130/0x830 [vmw_pvscsi]
[   15.678661]  [<ffffffff814ce2f0>] ? perf_trace_scsi_dispatch_cmd_error+0x1a0/0x1a0
[   15.679367]  [<ffffffff814ce8f1>] scsi_dispatch_cmd+0xb1/0x4e0
[   15.679999]  [<ffffffff814d627c>] scsi_request_fn+0x33c/0x540
[   15.680469]  [<ffffffff8135a603>] __blk_run_queue+0x33/0x40
[   15.681095]  [<ffffffff81363241>] blk_execute_rq_nowait+0xa1/0x120
[   15.681579]  [<ffffffff81363366>] blk_execute_rq+0x76/0x100
[   15.682213]  [<ffffffff8135911f>] ? blk_rq_init+0xff/0x170
[   15.682707]  [<ffffffff81363650>] ? blk_recount_segments+0x20/0x40
[   15.683359]  [<ffffffff81241209>] ? bio_phys_segments+0x19/0x20
[   15.684013]  [<ffffffff8135e890>] ? blk_rq_bio_prep+0x70/0xd0
[   15.684469]  [<ffffffff813630f0>] ? blk_rq_map_kern+0xc0/0x170
[   15.685107]  [<ffffffff814d4d87>] scsi_execute+0xd7/0x160
[   15.685556]  [<ffffffff814d656c>] scsi_execute_req_flags+0x8c/0x100
[   15.686201]  [<ffffffff814d898c>] scsi_probe_and_add_lun+0x20c/0xc00
[   15.686687]  [<ffffffff814d97f8>] __scsi_scan_target+0xf8/0x6a0
[   15.687330]  [<ffffffff810d8339>] ? mark_held_locks+0xb9/0x140
[   15.687986]  [<ffffffff81771196>] ? _raw_spin_unlock_irqrestore+0x36/0x70
[   15.692147]  [<ffffffff810d84c5>] ? trace_hardirqs_on_caller+0x105/0x1d0
[   15.692661]  [<ffffffff810d859d>] ? trace_hardirqs_on+0xd/0x10
[   15.693345]  [<ffffffff814d9f16>] scsi_scan_channel.part.6+0x66/0x90
[   15.694016]  [<ffffffff814da0d9>] scsi_scan_host_selected+0xf9/0x1c0
[   15.694497]  [<ffffffff814da231>] do_scsi_scan_host+0x91/0xa0
[   15.695125]  [<ffffffff814da40c>] do_scan_async+0x1c/0x160
[   15.695574]  [<ffffffff810ae389>] async_run_entry_fn+0x39/0x120
[   15.696229]  [<ffffffff8109d4c1>] process_one_work+0x211/0x6b0
[   15.696689]  [<ffffffff8109d455>] ? process_one_work+0x1a5/0x6b0
[   15.697332]  [<ffffffff8109da7b>] worker_thread+0x11b/0x3a0
[   15.697958]  [<ffffffff8109d960>] ? process_one_work+0x6b0/0x6b0
[   15.698423]  [<ffffffff810a6550>] kthread+0xf0/0x110
[   15.699031]  [<ffffffff81021f59>] ? sched_clock+0x9/0x10
[   15.699472]  [<ffffffff810a6460>] ? insert_kthread_work+0x80/0x80
[   15.700112]  [<ffffffff8177afbc>] ret_from_fork+0x7c/0xb0
[   15.700587]  [<ffffffff810a6460>] ? insert_kthread_work+0x80/0x80
[   15.701261] ---[ end trace 9e665d6a1a3e2037 ]---
[   15.701676] Mapped at:
[   15.702234]  [<ffffffff813b4081>] debug_dma_map_page+0x91/0x140
[   15.702722]  [<ffffffffa00018a1>] pvscsi_queue+0x281/0x830 [vmw_pvscsi]
[   15.703360]  [<ffffffff814ce8f1>] scsi_dispatch_cmd+0xb1/0x4e0
[   15.704018]  [<ffffffff814d627c>] scsi_request_fn+0x33c/0x540
[   15.704530]  [<ffffffff8135a603>] __blk_run_queue+0x33/0x40
[   15.706915] scsi 2:0:0:0: Direct-Access     VMware,  VMware Virtual S 1.0  PQ: 0 ANSI: 2
[   15.708230] scsi 2:0:1:0: Direct-Access     VMware,  VMware Virtual S 1.0  PQ: 0 ANSI: 2