Re: Can not allocate memory for KERN_MSGBUF

[Mark Kettenis]

This happens if kernel and the dmesg(8) userland program are out of
sync.  And yes, that can even happen for snapshots.  Next snapshot
should be ok again.

Re: Can not allocate memory for KERN_MSGBUF

[Andreas Kusalananda Kähäri]

On Fri, Jun 24, 2016 at 01:19:32PM +0200, Alexander Bluhm wrote:
> On Fri, Jun 24, 2016 at 10:30:04AM +0200, Andreas Kusalananda K?h?ri wrote:
> > I'm following -current on amd64, running in VirtualBox.  I recompiled
> > the kernel today with fresh sources, like I do a few times a week on
> > slow days.
> 
> Have you also installed /usr/include/sys/msgbuf.h from
> /usr/src/sys/sys/msgbuf.h and recomiled /usr/src/sbin/dmesg ?
> A make build should do that.
> 
> bluhm
> 

I believe I have fallen into the trap of not recompiling the userland
binaries before reacting te seeing the dmesg command misbehave.

I was doing a regular update of the system so I recompiled the kernel
and rebooted.  I have a piece of shell code in my login scripts that
compares the dmsg output from the current boot with that of the previous
boot, and when I saw that there was no output from the current boot I
reacted before thinking.


I am sincerely sorry for the noise.

Regards,


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Re: Can not allocate memory for KERN_MSGBUF

[Alexander Bluhm]

On Fri, Jun 24, 2016 at 10:30:04AM +0200, Andreas Kusalananda K?h?ri wrote:
> I'm following -current on amd64, running in VirtualBox.  I recompiled
> the kernel today with fresh sources, like I do a few times a week on
> slow days.

Have you also installed /usr/include/sys/msgbuf.h from
/usr/src/sys/sys/msgbuf.h and recomiled /usr/src/sbin/dmesg ?
A make build should do that.

bluhm

Can not allocate memory for KERN_MSGBUF

[Andreas Kusalananda Kähäri]

On Thu, Jun 23, 2016 at 07:15:21AM -0600, Alexander Bluhm wrote:
> CVSROOT:  /cvs
> Module name:  src
> Changes by:   bl...@cvs.openbsd.org   2016/06/23 07:15:21
> 
> Modified files:
>   sys/kern   : subr_log.c 
>   sys/sys: msgbuf.h 
> 
> Log message:
> It is annoying that the dmesg buffer can overflow and loose messages
> undetected during debugging.  To make clear what happens, count the
> dropped bytes and write message buffer full to syslogd.  This also
> helps to have a reliable log system.
> OK deraadt@ millert@ tedu@
> 

Hi,

I'm following -current on amd64, running in VirtualBox.  I recompiled
the kernel today with fresh sources, like I do a few times a week on
slow days.

After reboot:

$ dmesg
dmesg: sysctl: KERN_MSGBUF: Cannot allocate memory

I have no /etc/sysctl.conf and I don't set those variables by
hand.

The issue *seems* to have been introduced with the commit above
as backing it out fixes it.

dmesg output without the commit (or any later commit):

OpenBSD 6.0-beta (GENERIC.MP) #26: Fri Jun 24 10:16:28 CEST 2016
kk@uerfale:/sys/arch/amd64/compile/GENERIC.MP
real mem = 4278124544 (4079MB)
avail mem = 4143943680 (3951MB)
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: rev 2
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 0xfee0: PC-AT compat
cpu0 at mainbus0: apid 0 (boot processor)
cpu0: Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz, 3193.07 MHz
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,SSE4.1,SSE4.2,MOVBE,POPCNT,AES,XSAVE,AVX,RDRAND,NXE,LONG,LAHF,ABM,ITSC
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) i5-4570 CPU @ 3.20GHz, 3192.77 MHz
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,SSE4.1,SSE4.2,MOVBE,POPCNT,AES,XSAVE,AVX,RDRAND,NXE,LONG,LAHF,ABM,ITSC
cpu1: 256KB 64b/line 8-way L2 cache
cpu1: smt 0, core 1, package 0
ioapic0 at mainbus0: apid 2 pa 0xfec0, version 11, 24 pins
acpiprt0 at acpi0: bus 0 (PCI0)
acpicpu0 at acpi0: C1(@1 halt!)
acpicpu1 at acpi0: C1(@1 halt!)
"PNP0303" at acpi0 not configured
"PNP0F03" at acpi0 not configured
acpiac0 at acpi0: AC unit online
acpivideo0 at acpi0: GFX0
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
pciide0 at pci0 dev 1 function 1 "Intel 82371AB IDE" rev 0x01: DMA, channel 0 
configured to compatibility, channel 1 configured to compatibility
wd0 at pciide0 channel 0 drive 0: 
wd0: 128-sector PIO, LBA, 51200MB, 104857600 sectors
wd0(pciide0:0:0): using PIO mode 4, Ultra-DMA mode 2
atapiscsi0 at pciide0 channel 1 drive 0
scsibus1 at atapiscsi0: 2 targets
cd0 at scsibus1 targ 0 lun 0:  ATAPI 5/cdrom removable
cd0(pciide0:1:0): using PIO mode 4, Ultra-DMA mode 2
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 82543GC" rev 0x02: apic 2 int 19, address 
08:00:27:b1:89:72
"InnoTek VirtualBox Guest Service" rev 0x00 at pci0 dev 4 function 0 not 
configured
piixpm0 at pci0 dev 7 function 0 "Intel 82371AB Power" rev 0x08: SMBus disabled
em1 at pci0 dev 8 function 0 "Intel 82543GC" rev 0x02: apic 2 int 16, address 
08:00:27:ff:fb:ca
isa0 at pcib0
isadma0 at isa0
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
vscsi0 at root
scsibus2 at vscsi0: 256 targets
softraid0 at root
scsibus3 at softraid0: 256 targets
root on wd0a (22d20e8d1f94fa20.a) swap on wd0b dump on wd0b


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