>Synopsis: With large line numbers, tail(1) makes the system unusable.
>Category: system
>Environment:
        System      : OpenBSD 6.0
        Details     : OpenBSD 6.0 (GENERIC) #2148: Tue Jul 26 12:55:20
MDT 2016
                         dera...@amd64.openbsd.org:/usr/src/sys/arch/am
d64/compile/GENERIC

        Architecture: OpenBSD.amd64
        Machine     : amd64
>Description:
When provided with a large line number, tail gives "Cannot allocate
memory" to a regular user, but when run as root tail gets stuck making
the system unusable.

The same issue exists on 5.9 too. Note that I see a couple of changes
to tail on 5.9 Changelog.

>How-To-Repeat:
Simply run the following command line as root:

echo blah | /usr/bin/tail -99999999

Normally, it should print blah and exit, or give "Cannot allocate
memory" as it does to a regular user. (Note that tail on Linux prints
blah or gives "Numerical result out of range" for much larger numbers,
to both regular users and root.)

>Fix:
Workaroud: Do not use such large numbers.

dmesg:
OpenBSD 6.0 (GENERIC) #2148: Tue Jul 26 12:55:20 MDT 2016
    dera...@amd64.openbsd.org:/usr/src/sys/arch/amd64/compile/GENERIC
real mem = 1056899072 (1007MB)
avail mem = 1020502016 (973MB)
mpath0 at root
scsibus0 at mpath0: 256 targets
mainbus0 at root
bios0 at mainbus0: SMBIOS rev. 2.7 @ 0xe0010 (239 entries)
bios0: vendor Phoenix Technologies LTD version "6.00" date 07/02/2015
bios0: VMware, Inc. VMware Virtual Platform
acpi0 at bios0: rev 2
acpi0: sleep states S0 S1 S4 S5
acpi0: tables DSDT FACP BOOT APIC MCFG SRAT HPET WAET
acpi0: wakeup devices PCI0(S3) USB_(S1) P2P0(S3) S1F0(S3) S2F0(S3)
S3F0(S3) S4F0(S3) S5F0(S3) S6F0(S3) S7F0(S3) S8F0(S3) S9F0(S3) S10F(S3)
S11F(S3) S12F(S3) S13F(S3) [...]
acpitimer0 at acpi0: 3579545 Hz, 24 bits
acpimadt0 at acpi0 addr 0xfee00000: PC-AT compat
cpu0 at mainbus0: apid 0 (boot processor)
cpu0: Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz, 2592.16 MHz
cpu0:
FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36
,CFLUSH,DS,MMX,FXSR,SSE,SSE2,SS,SSE3,PCLMUL,VMX,SSSE3,FMA3,CX16,PCID,SS
E4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND,HV,N
XE,PAGE1GB,LONG,LAHF,ABM,3DNOWP,PERF,ITSC,FSGSBASE,BMI1,HLE,AVX2,SMEP,B
MI2,ERMS,INVPCID,RTM,RDSEED,ADX,SMAP,SENSOR,ARAT
cpu0: 256KB 64b/line 8-way L2 cache
cpu0: smt 0, core 0, package 0
mtrr: Pentium Pro MTRR support, 8 var ranges, 88 fixed ranges
cpu0: apic clock running at 65MHz
ioapic0 at mainbus0: apid 1 pa 0xfec00000, version 11, 24 pins
acpimcfg0 at acpi0 addr 0xf0000000, bus 0-127
acpihpet0 at acpi0: 14318179 Hz
acpiprt0 at acpi0: bus 0 (PCI0)
acpicpu0 at acpi0: C1(@1 halt!)
"PNP0001" at acpi0 not configured
"PNP0303" at acpi0 not configured
"VMW0003" at acpi0 not configured
"PNP0A05" at acpi0 not configured
acpibat0 at acpi0: BAT1 model "VMware Virtual Batt"
acpiac0 at acpi0: AC unit online
pvbus0 at mainbus0: VMware
vmt0 at pvbus0
pci0 at mainbus0 bus 0
pchb0 at pci0 dev 0 function 0 "Intel 82443BX AGP" rev 0x01
ppb0 at pci0 dev 1 function 0 "Intel 82443BX AGP" rev 0x01
pci1 at ppb0 bus 1
pcib0 at pci0 dev 7 function 0 "Intel 82371AB PIIX4 ISA" rev 0x08
pciide0 at pci0 dev 7 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: <VMware Virtual IDE Hard Drive>
wd0: 64-sector PIO, LBA, 8192MB, 16777216 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: <NECVMWar, VMware IDE CDR10, 1.00> ATAPI
5/cdrom removable
cd0(pciide0:1:0): using PIO mode 4, Ultra-DMA mode 2
piixpm0 at pci0 dev 7 function 3 "Intel 82371AB Power" rev 0x08: SMBus
disabled
"VMware VMCI" rev 0x10 at pci0 dev 7 function 7 not configured
vga1 at pci0 dev 15 function 0 "VMware SVGA II" rev 0x00
wsdisplay0 at vga1 mux 1: console (80x25, vt100 emulation)
wsdisplay0: screen 1-5 added (80x25, vt100 emulation)
mpi0 at pci0 dev 16 function 0 "Symbios Logic 53c1030" rev 0x01: apic 1
int 17
mpi0: 0, firmware 1.3.41.32
scsibus2 at mpi0: 16 targets, initiator 7
ppb1 at pci0 dev 17 function 0 "VMware PCI" rev 0x02
pci2 at ppb1 bus 2
em0 at pci2 dev 0 function 0 "Intel 82545EM" rev 0x01: apic 1 int 18,
address 00:0c:29:5b:7e:3d
eap0 at pci2 dev 1 function 0 "Ensoniq AudioPCI97" rev 0x02: apic 1 int
19
ac97: codec id 0x43525913 (Cirrus Logic CS4297A rev 3)
audio0 at eap0
midi0 at eap0: <AudioPCI MIDI UART>
ppb2 at pci0 dev 21 function 0 "VMware PCIE" rev 0x01
pci3 at ppb2 bus 3
ppb3 at pci0 dev 21 function 1 "VMware PCIE" rev 0x01
pci4 at ppb3 bus 4
ppb4 at pci0 dev 21 function 2 "VMware PCIE" rev 0x01
pci5 at ppb4 bus 5
ppb5 at pci0 dev 21 function 3 "VMware PCIE" rev 0x01
pci6 at ppb5 bus 6
ppb6 at pci0 dev 21 function 4 "VMware PCIE" rev 0x01
pci7 at ppb6 bus 7
ppb7 at pci0 dev 21 function 5 "VMware PCIE" rev 0x01
pci8 at ppb7 bus 8
ppb8 at pci0 dev 21 function 6 "VMware PCIE" rev 0x01
pci9 at ppb8 bus 9
ppb9 at pci0 dev 21 function 7 "VMware PCIE" rev 0x01
pci10 at ppb9 bus 10
ppb10 at pci0 dev 22 function 0 "VMware PCIE" rev 0x01
pci11 at ppb10 bus 11
ppb11 at pci0 dev 22 function 1 "VMware PCIE" rev 0x01
pci12 at ppb11 bus 12
ppb12 at pci0 dev 22 function 2 "VMware PCIE" rev 0x01
pci13 at ppb12 bus 13
ppb13 at pci0 dev 22 function 3 "VMware PCIE" rev 0x01
pci14 at ppb13 bus 14
ppb14 at pci0 dev 22 function 4 "VMware PCIE" rev 0x01
pci15 at ppb14 bus 15
ppb15 at pci0 dev 22 function 5 "VMware PCIE" rev 0x01
pci16 at ppb15 bus 16
ppb16 at pci0 dev 22 function 6 "VMware PCIE" rev 0x01
pci17 at ppb16 bus 17
ppb17 at pci0 dev 22 function 7 "VMware PCIE" rev 0x01
pci18 at ppb17 bus 18
ppb18 at pci0 dev 23 function 0 "VMware PCIE" rev 0x01
pci19 at ppb18 bus 19
ppb19 at pci0 dev 23 function 1 "VMware PCIE" rev 0x01
pci20 at ppb19 bus 20
ppb20 at pci0 dev 23 function 2 "VMware PCIE" rev 0x01
pci21 at ppb20 bus 21
ppb21 at pci0 dev 23 function 3 "VMware PCIE" rev 0x01
pci22 at ppb21 bus 22
ppb22 at pci0 dev 23 function 4 "VMware PCIE" rev 0x01
pci23 at ppb22 bus 23
ppb23 at pci0 dev 23 function 5 "VMware PCIE" rev 0x01
pci24 at ppb23 bus 24
ppb24 at pci0 dev 23 function 6 "VMware PCIE" rev 0x01
pci25 at ppb24 bus 25
ppb25 at pci0 dev 23 function 7 "VMware PCIE" rev 0x01
pci26 at ppb25 bus 26
ppb26 at pci0 dev 24 function 0 "VMware PCIE" rev 0x01
pci27 at ppb26 bus 27
ppb27 at pci0 dev 24 function 1 "VMware PCIE" rev 0x01
pci28 at ppb27 bus 28
ppb28 at pci0 dev 24 function 2 "VMware PCIE" rev 0x01
pci29 at ppb28 bus 29
ppb29 at pci0 dev 24 function 3 "VMware PCIE" rev 0x01
pci30 at ppb29 bus 30
ppb30 at pci0 dev 24 function 4 "VMware PCIE" rev 0x01
pci31 at ppb30 bus 31
ppb31 at pci0 dev 24 function 5 "VMware PCIE" rev 0x01
pci32 at ppb31 bus 32
ppb32 at pci0 dev 24 function 6 "VMware PCIE" rev 0x01
pci33 at ppb32 bus 33
ppb33 at pci0 dev 24 function 7 "VMware PCIE" rev 0x01
pci34 at ppb33 bus 34
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
scsibus3 at vscsi0: 256 targets
softraid0 at root
scsibus4 at softraid0: 256 targets
root on wd0a (45b2e1c181bbb06c.a) swap on wd0b dump on wd0b

usbdevs:
usbdevs: no USB controllers found

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