Panic: _at_r323525: iflib

My build machine didn't have the problem -- unfortunately (as I have a
serial console on it).  The laptop did....  The panic occurs immediately
after probing the NICs (so the good news is that it didn't have a chance
yet to mount any filesystems; the bad news is that there's no dump
available).  (In transcribing the backtrace, I realized that the laptop
has an em(4) device; the build machine does not.  And iflib appears to
be implicated.)

I used my phone to grab screeshots of the backtrace... and the program I
run on the phone to act as an SSH server so I can get the photos from it
has suddenly become completely confused as to what the IP address of the
phone is on the local network (using an unreachable 10/8 address; at
this point, I won't waste my time trying to figure out how THAT broke).

I did try clearing /usr/obj/usr/src/sys/CANARY/* and rebuilding the
kernel, but the symptom persists.  (I am using "WITH_META_MODE=yes".)

Previous successful build was:
FreeBSD g1-252.catwhisker.org 12.0-CURRENT FreeBSD 12.0-CURRENT #398  r323483M/323489:1200044: Tue Sep 12 04:31:08 PDT 2017     root_at_g1-252.catwhisker.org:/common/S4/obj/usr/src/sys/CANARY  amd64

The usual historical information, including a verbose-boot dmesg.boot
from the above-cited build, may be found at
<http://www.catwhisker.org/~david/FreeBSD/history/>.

I will try hand-transcribing some of the lock & backtrace info:

...
em0: allocated for 1 rx_queues
Kernel page fault with the following non-sleepable locks held:
exclusive sleep mutex taskqgroup (taskqgroup) r = 0 (0xfffffe07be2e4800) locked _at_ /usr/src/sys/kern/subr_gtaskqueue.c:803
stack backtrace:  [which I am abbreviating at this point -- dhw]
#0 ... at witness_debugger+0x73
#1 ... at witness_warn+0x43f
#2 ... at trap_pfault+0x53
#3 ... at trap+0x2c5
#4 ... at calltrap+0x8
#5 ... at iflib_device_register+0x2a61
#6 ... at iflib_device_attach+0xb7
#7 ... at device_attach+0x3ee
#8 ... at bus_generic_attach+0x5a
#9 ... at pci_attach+0xd5
#10 ... at device_attach+0x3ee
#11 ... at bus_generic_attach+0x5a
#12 ... at acpi_pcib_acpi_attach+0x3bc
#13 ... at device_attach+0x3ee
#14 ... at bus_generic_attach+0x5a
#15 ... at acpi_attach+0xe85
#16 ... at device_attach+0x3ee
#17 ... at bus_generic_attach+0x5a

Fatal trap 12: page fault while in kernel mode
cpuid = 2; apic id = 02
fault virtual address   = 0xffffffff8b530c20
fault code              = supervisor write data, page not present
...
[ thread pid 0 tid 100000 ]
Stopped at      0xffffffff80a743b0 = taskqgroup_attach+0x230:    orq   %rax,-0x 58(%rbp,%xrx,8)

I can provide more specific excerpts, but I need to focus on some
other activities for a while.

Peace,
david
-- 
David H. Wolfskill				david_at_catwhisker.org
http://www.cbc.ca/news/opinion/donald-trump-playbook-1.4265374

See http://www.catwhisker.org/~david/publickey.gpg for my public key.