>Synopsis: Concurrent rename/mkdir/rmdir on a hierarchy hangs the system
>Category: Kernel bug
>Environment:
System : OpenBSD 6.8
Details : OpenBSD 6.8-current (GENERIC.MP) #7: Mon Oct 5 22:45:13
CEST 2020
[email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
Architecture: OpenBSD.amd64
Machine : amd64
>Description:
Running dirconc.c [1] leads the system to hang under a minute, no ssh, no
serial it's a full freeze. Upon reboot the fs is obviously corrupted and needs
to go to single user mode to fix up.
This is on a recent snapshot (dmesg indicates a compiled kernel cause I added
some debug code to no help).
Tweaking a bit dirconc to lower the number of concurrent ops doesn't help. Using
procs instead of threads also leads to the same hang.
I intended to pinpoint it a bit better (that's why it's in a VM), but the hard
hang makes it really difficult and I lack the time and knowledge in that area
so I'm reporting it (I'll keep trying to debug it though and keep you updated).
>How-To-Repeat:
Get dirconc.c [1], build it (cc dirconc.c -lpthread for the threaded version),
and
run dirconc against an empty directory. After a while the system will hang.
>Fix:
No known fix.
[1]: https://www.netbsd.org/~riastradh/tmp/dirconc.c
dmesg:
OpenBSD 6.8-current (GENERIC.MP) #7: Mon Oct 5 22:45:13 CEST 2020
[email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
real mem = 4278124544 (4079MB)
avail mem = 4133400576 (3941MB)
random: good seed from bootblocks
mpath0 at root
scsibus0 at mpath0: 256 targets
mainbus0 at root
bios0 at mainbus0: SMBIOS rev. 2.5 @ 0xe1000 (10 entries)
bios0: vendor innotek GmbH version "VirtualBox" date 12/01/2006
bios0: innotek GmbH VirtualBox
acpi0 at bios0: ACPI 4.0
acpi0: sleep states S0 S5
acpi0: tables DSDT FACP APIC SSDT
acpi0: wakeup devices
acpitimer0 at acpi0: 3579545 Hz, 32 bits
acpimadt0 at acpi0 addr 0xfee00000: PC-AT compat
cpu0 at mainbus0: apid 0 (boot processor)
cpu0: Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz, 2403.41 MHz, 06-4e-03
cpu0:
FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,MMX,FXSR,SSE,SSE2,HTT,SSE3,PCLMUL,SSSE3,CX16,PCID,SSE4.1,SSE4.2,MOVBE,POPCNT,AES,XSAVE,AVX,RDRAND,NXE,RDTSCP,LONG,LAHF,ABM,3DNOWP,ITSC,FSGSBASE,AVX2,INVPCID,RDSEED,CLFLUSHOPT,MELTDOWN
cpu0: 256KB 64b/line 8-way L2 cache
cpu0: smt 0, core 0, package 0
mtrr: CPU supports MTRRs but not enabled by BIOS
cpu0: apic clock running at 1000MHz
cpu1 at mainbus0: apid 1 (application processor)
cpu1: Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz, 2400.10 MHz, 06-4e-03
cpu1:
FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,MMX,FXSR,SSE,SSE2,HTT,SSE3,PCLMUL,SSSE3,CX16,PCID,SSE4.1,SSE4.2,MOVBE,POPCNT,AES,XSAVE,AVX,RDRAND,NXE,RDTSCP,LONG,LAHF,ABM,3DNOWP,ITSC,FSGSBASE,AVX2,INVPCID,RDSEED,CLFLUSHOPT,MELTDOWN
cpu1: 256KB 64b/line 8-way L2 cache
cpu1: smt 0, core 1, package 0
cpu2 at mainbus0: apid 2 (application processor)
cpu2: Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz, 2400.09 MHz, 06-4e-03
cpu2:
FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,MMX,FXSR,SSE,SSE2,HTT,SSE3,PCLMUL,SSSE3,CX16,PCID,SSE4.1,SSE4.2,MOVBE,POPCNT,AES,XSAVE,AVX,RDRAND,NXE,RDTSCP,LONG,LAHF,ABM,3DNOWP,ITSC,FSGSBASE,AVX2,INVPCID,RDSEED,CLFLUSHOPT,MELTDOWN
cpu2: 256KB 64b/line 8-way L2 cache
cpu2: disabling user TSC (skew=161)
cpu2: smt 0, core 2, package 0
cpu3 at mainbus0: apid 3 (application processor)
cpu3: Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz, 2400.09 MHz, 06-4e-03
cpu3:
FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,MMX,FXSR,SSE,SSE2,HTT,SSE3,PCLMUL,SSSE3,CX16,PCID,SSE4.1,SSE4.2,MOVBE,POPCNT,AES,XSAVE,AVX,RDRAND,NXE,RDTSCP,LONG,LAHF,ABM,3DNOWP,ITSC,FSGSBASE,AVX2,INVPCID,RDSEED,CLFLUSHOPT,MELTDOWN
cpu3: 256KB 64b/line 8-way L2 cache
cpu3: disabling user TSC (skew=282)
cpu3: smt 0, core 3, package 0
ioapic0 at mainbus0: apid 4 pa 0xfec00000, version 20, 24 pins, remapped
acpiprt0 at acpi0: bus 0 (PCI0)
acpipci0 at acpi0 PCI0: 0x00000000 0x00000011 0x00000001
acpibat0 at acpi0: BAT0 model "1" serial 0 type VBOX oem "innotek"
acpiac0 at acpi0: AC unit online
acpicpu0 at acpi0: C1(@1 halt!)
acpicpu1 at acpi0: C1(@1 halt!)
acpicpu2 at acpi0: C1(@1 halt!)
acpicpu3 at acpi0: C1(@1 halt!)
acpivideo0 at acpi0: GFX0
cpu0: using Skylake AVX MDS workaround
pci0 at mainbus0 bus 0
pchb0 at pci0 dev 0 function 0 "Intel 82441FX" rev 0x02
pcib0 at pci0 dev 1 function 0 "Intel 82371SB ISA" rev 0x00
vga1 at pci0 dev 2 function 0 "InnoTek VirtualBox Graphics Adapter" rev 0x00
wsdisplay0 at vga1 mux 1: console (80x25, vt100 emulation)
wsdisplay0: screen 1-5 added (80x25, vt100 emulation)
em0 at pci0 dev 3 function 0 "Intel 82540EM" rev 0x02: apic 4 int 19, address
08:00:27:ea:09:c8
"InnoTek VirtualBox Guest Service" rev 0x00 at pci0 dev 4 function 0 not
configured
auich0 at pci0 dev 5 function 0 "Intel 82801AA AC97" rev 0x01: apic 4 int 21,
ICH
ac97: codec id 0x83847600 (SigmaTel STAC9700)
audio0 at auich0
ohci0 at pci0 dev 6 function 0 "Apple Intrepid USB" rev 0x00: apic 4 int 22,
version 1.0
piixpm0 at pci0 dev 7 function 0 "Intel 82371AB Power" rev 0x08: apic 4 int 23
iic0 at piixpm0
ehci0 at pci0 dev 11 function 0 "Intel 82801FB USB" rev 0x00: apic 4 int 19
usb0 at ehci0: USB revision 2.0
uhub0 at usb0 configuration 1 interface 0 "Intel EHCI root hub" rev 2.00/1.00
addr 1
ahci0 at pci0 dev 13 function 0 "Intel 82801HBM AHCI" rev 0x02: apic 4 int 21,
AHCI 1.1
ahci0: device on port 0 didn't come ready, TFD: 0x131<ERR>
ahci0: port 0: 3.0Gb/s
ahci0: device on port 1 didn't come ready, TFD: 0x171<ERR>
ahci0: port 1: 3.0Gb/s
scsibus1 at ahci0: 32 targets
cd0 at scsibus1 targ 0 lun 0: <VBOX, CD-ROM, 1.0> removable
sd0 at scsibus1 targ 1 lun 0: <ATA, VBOX HARDDISK, 1.0>
t10.ATA_VBOX_HARDDISK_VB954da61f-210850d3_
sd0: 81920MB, 512 bytes/sector, 167772160 sectors
isa0 at pcib0
isadma0 at isa0
com0 at isa0 port 0x3f8/8 irq 4: ns16550a, 16 byte fifo
com0: probed fifo depth: 1 bytes
pckbc0 at isa0 port 0x60/5 irq 1 irq 12
pckbd0 at pckbc0 (kbd slot)
wskbd0 at pckbd0: console keyboard, using wsdisplay0
pms0 at pckbc0 (aux slot)
wsmouse0 at pms0 mux 0
pcppi0 at isa0 port 0x61
spkr0 at pcppi0
usb1 at ohci0: USB revision 1.0
uhub1 at usb1 configuration 1 interface 0 "Apple OHCI root hub" rev 1.00/1.00
addr 1
dt: 439 probes
vscsi0 at root
scsibus2 at vscsi0: 256 targets
softraid0 at root
scsibus3 at softraid0: 256 targets
root on sd0a (e08db1e8dc1d78ca.a) swap on sd0b dump on sd0b
usbdevs:
Controller /dev/usb0:
addr 01: 8086:0000 Intel, EHCI root hub
high speed, self powered, config 1, rev 1.00
driver: uhub0
Controller /dev/usb1:
addr 01: 106b:0000 Apple, OHCI root hub
full speed, self powered, config 1, rev 1.00
driver: uhub1
