New warnings from WITNESS

[Michael Tuexen]

Dear all,

when booting a recent kernel

[freebsd12:~] tuexen% uname -a
FreeBSD freebsd12.testbed 12.0-CURRENT FreeBSD 12.0-CURRENT #702 r308359M: Sun Nov  6 11:55:17 CET 2016     tuexen at freebsd12.testbed:/usr/home/tuexen/head/sys/amd64/compile/SCTP  amd64

on a VMWare Fusion VM, I get a lot of warnings like

bus_dmamap_create with the following non-sleepable locks held:
exclusive sleep mutex mpt (mpt) r = 0 (0xfffffe0000e2f008) locked @ dev/mpt/mpt.c:2287
stack backtrace:
#0 0xffffffff80ac0300 at witness_debugger+0x70
#1 0xffffffff80ac15e7 at witness_warn+0x3d7
#2 0xffffffff81055fef at bus_dmamap_create+0x2f
#3 0xffffffff80678a25 at mpt_configure_ioc+0x3a5
#4 0xffffffff80677476 at mpt_attach+0x226
#5 0xffffffff80683299 at mpt_pci_attach+0x9c9
#6 0xffffffff80a9478d at device_attach+0x41d
#7 0xffffffff80a9595a at bus_generic_attach+0x4a
#8 0xffffffff806ebe75 at pci_attach+0xd5
#9 0xffffffff80a9478d at device_attach+0x41d
#10 0xffffffff80a9595a at bus_generic_attach+0x4a
#11 0xffffffff803c11a2 at acpi_pcib_acpi_attach+0x402
#12 0xffffffff80a9478d at device_attach+0x41d
#13 0xffffffff80a9595a at bus_generic_attach+0x4a
#14 0xffffffff803b4c8f at acpi_attach+0xdbf
#15 0xffffffff80a9478d at device_attach+0x41d
#16 0xffffffff80a9595a at bus_generic_attach+0x4a
#17 0xffffffff80ee03e3 at nexus_acpi_attach+0x73
bus_dmamap_create with the following non-sleepable locks held:
exclusive sleep mutex mpt (mpt) r = 0 (0xfffffe0000e2f008) locked @ dev/mpt/mpt.c:2287
stack backtrace:
#0 0xffffffff80ac0300 at witness_debugger+0x70
#1 0xffffffff80ac15e7 at witness_warn+0x3d7
#2 0xffffffff81055fef at bus_dmamap_create+0x2f
#3 0xffffffff80678a25 at mpt_configure_ioc+0x3a5
#4 0xffffffff80677476 at mpt_attach+0x226
#5 0xffffffff80683299 at mpt_pci_attach+0x9c9
#6 0xffffffff80a9478d at device_attach+0x41d
#7 0xffffffff80a9595a at bus_generic_attach+0x4a
#8 0xffffffff806ebe75 at pci_attach+0xd5
#9 0xffffffff80a9478d at device_attach+0x41d
#10 0xffffffff80a9595a at bus_generic_attach+0x4a
#11 0xffffffff803c11a2 at acpi_pcib_acpi_attach+0x402
#12 0xffffffff80a9478d at device_attach+0x41d
#13 0xffffffff80a9595a at bus_generic_attach+0x4a
#14 0xffffffff803b4c8f at acpi_attach+0xdbf
#15 0xffffffff80a9478d at device_attach+0x41d
#16 0xffffffff80a9595a at bus_generic_attach+0x4a
#17 0xffffffff80ee03e3 at nexus_acpi_attach+0x73
bus_dmamap_create with the following non-sleepable locks held:
exclusive sleep mutex mpt (mpt) r = 0 (0xfffffe0000e2f008) locked @ dev/mpt/mpt.c:2287
stack backtrace:
#0 0xffffffff80ac0300 at witness_debugger+0x70
#1 0xffffffff80ac15e7 at witness_warn+0x3d7
#2 0xffffffff81055fef at bus_dmamap_create+0x2f
#3 0xffffffff80678a25 at mpt_configure_ioc+0x3a5
#4 0xffffffff80677476 at mpt_attach+0x226
#5 0xffffffff80683299 at mpt_pci_attach+0x9c9
#6 0xffffffff80a9478d at device_attach+0x41d
#7 0xffffffff80a9595a at bus_generic_attach+0x4a
#8 0xffffffff806ebe75 at pci_attach+0xd5
#9 0xffffffff80a9478d at device_attach+0x41d
#10 0xffffffff80a9595a at bus_generic_attach+0x4a
#11 0xffffffff803c11a2 at acpi_pcib_acpi_attach+0x402
#12 0xffffffff80a9478d at device_attach+0x41d
#13 0xffffffff80a9595a at bus_generic_attach+0x4a
#14 0xffffffff803b4c8f at acpi_attach+0xdbf
#15 0xffffffff80a9478d at device_attach+0x41d
#16 0xffffffff80a9595a at bus_generic_attach+0x4a
#17 0xffffffff80ee03e3 at nexus_acpi_attach+0x73
bus_dmamap_create with the following non-sleepable locks held:
exclusive sleep mutex mpt (mpt) r = 0 (0xfffffe0000e2f008) locked @ dev/mpt/mpt.c:2287
stack backtrace:
#0 0xffffffff80ac0300 at witness_debugger+0x70
#1 0xffffffff80ac15e7 at witness_warn+0x3d7
#2 0xffffffff81055fef at bus_dmamap_create+0x2f
#3 0xffffffff80678a25 at mpt_configure_ioc+0x3a5
#4 0xffffffff80677476 at mpt_attach+0x226
#5 0xffffffff80683299 at mpt_pci_attach+0x9c9
#6 0xffffffff80a9478d at device_attach+0x41d
#7 0xffffffff80a9595a at bus_generic_attach+0x4a
#8 0xffffffff806ebe75 at pci_attach+0xd5
#9 0xffffffff80a9478d at device_attach+0x41d
#10 0xffffffff80a9595a at bus_generic_attach+0x4a
#11 0xffffffff803c11a2 at acpi_pcib_acpi_attach+0x402
#12 0xffffffff80a9478d at device_attach+0x41d
#13 0xffffffff80a9595a at bus_generic_attach+0x4a
#14 0xffffffff803b4c8f at acpi_attach+0xdbf
#15 0xffffffff80a9478d at device_attach+0x41d
#16 0xffffffff80a9595a at bus_generic_attach+0x4a
#17 0xffffffff80ee03e3 at nexus_acpi_attach+0x73

... and so on. Not sure which revision introduced it...

Best regards
Michael