"Could not open pipe:" - custom kernel hint?

From: C. Bensend <benny(at)bennyvision.com>
Date: Thu Dec 19 2002 - 17:31:56 EST

Hey folks,

        I'm running a network monitoring system on several i386 machines, either 3.1-STABLE or 3.2-STABLE. When a network link goes down (or some other failure happens that causes a bunch of tests to fail), my machines start logging a bunch of
"Could not open pipe: /path/to/program opt1 opt2 etc" errors.

        Soooo, I hit the man pages, looking specifically at fork(2) and pipe(2). fork(2) didn't appear to be relevant, as the number of processes spawned by this software never seem to become too excessive (less than 50, at the worst of times). However, pipe(2) looked promising. According to that one, the following items may cause pipe to fail:

• Too many descriptors are active
• The system file table is full
• The fildes buffer is in an invalid area of the process's address space

        What I'd like to know, is whether this problem can be solved by rolling a new kernel and adjusting some parameters, like perhaps the system file table or descriptors. I read through options(4), and didn't notice anything promising. I also did a little grepping through a listing of 'sysctl -a', but many of those things are a bit over my head.

        Does anyone a bit more intimate with the kernel have any ideas about what I can modify to try to solve this? Hopefully this isn't a stupid question, and I'm missing something silly.

Thanks much!

Benny

Dmesg from one of the boxes (custom kernel, the only mods from GENERIC are spurious drivers removed - I HAVE tried this with a GENERIC kernel, and whitnessed the same behavior):

OpenBSD 3.1-stable (BennyDeluxe) #2: Mon Oct 7 15:42:26 CDT 2002

    root@amwnagios:/usr/src/sys/arch/i386/compile/BennyDeluxe cpu0: Intel Pentium II (Klamath) ("GenuineIntel" 686-class, 512KB L2 cache) 300 MHz cpu0: FPU,V86,DE,PSE,TSC,MSR,PAE,MCE,CX8,SYS,MTRR,PGE,MCA,CMOV,MMX real mem = 268021760 (261740K)
avail mem = 245567488 (239812K)
using 3297 buffers containing 13504512 bytes (13188K) of memory mainbus0 (root)
bios0 at mainbus0: AT/286+(c2) BIOS, date 10/02/98, BIOS32 rev. 0 @ 0xfd79d pcibios0 at bios0: rev. 2.1 @ 0xfd730/0x8d0

pcibios0: PCI IRQ Routing Table rev. 1.0 @ 0xfdf40/160 (8 entries)
pcibios0: PCI Interrupt Router at 000:04:0 ("Intel 82371FB PCI-ISA" rev 0x00)
pcibios0: PCI bus #2 is the last bus

bios0: ROM list: 0xc0000/0x8000 0xc8000/0x4000 pci0 at mainbus0 bus 0: configuration mode 1 (no bios) pchb0 at pci0 dev 0 function 0 "Intel 82443LX PCI-AGP" rev 0x03 ppb0 at pci0 dev 1 function 0 "Intel 82443LX AGP" rev 0x03 pci1 at ppb0 bus 1
vga1 at pci1 dev 0 function 0 "Cirrus Logic CL-GD5465" rev 0x03 wsdisplay0 at vga1: console (80x25, vt100 emulation) wsdisplay0: screen 1-5 added (80x25, vt100 emulation) pcib0 at pci0 dev 4 function 0 "Intel 82371AB PIIX4 ISA" rev 0x01 pciide0 at pci0 dev 4 function 1 "Intel 82371AB IDE" rev 0x01: DMA, channel 0 wired to compatibility, channel 1 wired to compatibility atapiscsi0 at pciide0 channel 1 drive 0
scsibus0 at atapiscsi0: 2 targets
cd0 at scsibus0 targ 0 lun 0: <MATSHITA, CD-ROM CR-585, ZP18> SCSI0 5/cdrom removable wd0 at pciide0 channel 1 drive 1: <WDC WD102AA> wd0: 16-sector PIO, LBA, 9787MB, 16383 cyl, 16 head, 63 sec, 20044080 sectors cd0(pciide0:1:0): using PIO mode 0, DMA mode 1 wd0(pciide0:1:1): using PIO mode 4, Ultra-DMA mode 2
"Intel 82371AB USB" rev 0x01 at pci0 dev 4 function 2 not configured
"Intel 82371AB Power Mgmt" rev 0x01 at pci0 dev 4 function 3 not configured
ppb1 at pci0 dev 12 function 0 "DEC 21152 PCI-PCI" rev 0x02 pci2 at ppb1 bus 2
siop0 at pci2 dev 0 function 0 "Symbios Logic 53c875" rev 0x04: irq 11, has RAM scsibus1 at siop0: 16 targets
siop0: target 0 now using tagged 16 bit 20 MHz 16 REQ/ACK offset xfers sd0 at scsibus1 targ 0 lun 0: <QUANTUM, VIKING 4.5 WSE, 8808> SCSI2 0/direct fixed sd0: 4345MB, 6144 cyl, 8 head, 181 sec, 512 bytes/sec, 8899737 sec total le1 at pci2 dev 1 function 0 "AMD 79c970 PCnet-PCI LANCE" rev 0x25

le1: address 00:60:b0:ce:93:27
le1: 8 receive buffers, 2 transmit buffers
le1: interrupting at irq 9

isa0 at pcib0
isadma0 at isa0
pckbc0 at isa0 port 0x60/5
pckbd0 at pckbc0 (kbd slot)
pckbc0: using irq 1 for kbd slot
wskbd0 at pckbd0: console keyboard, using wsdisplay0 pcppi0 at isa0 port 0x61
sysbeep0 at pcppi0
lpt0 at isa0 port 0x378/4 irq 7
npx0 at isa0 port 0xf0/16: using exception 16 pccom0 at isa0 port 0x3f8/8 irq 4: ns16550a, 16 byte fifo fdc0 at isa0 port 0x3f0/6 irq 6 drq 2
fd0 at fdc0 drive 0: 1.44MB 80 cyl, 2 head, 18 sec biomask 8840 netmask 8a40 ttymask 8ac2
pctr: 686-class user-level performance counters enabled mtrr: Pentium Pro MTRR support
dkcsum: wd0 matched BIOS disk 81
dkcsum: sd0 matched BIOS disk 80
root on sd0a
rootdev=0x400 rrootdev=0xd00 rawdev=0xd02 Received on Thu Dec 19 17:35:58 2002