Date: Tue, 04 Apr 2000 20:56:38 +0300 From: Maxim Sobolev <sobomax@altavista.net> To: current@freebsd.org Subject: Dangerously looking glitch (4.0-STABLE) Message-ID: <38EA2CD6.24636F65@altavista.net>
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Hi,
I've tried to track down why my own script which is cleaning non-matching
distfiles from time to time produce incorrect results (just cvsup'ed 4.0).
After some digging I've found that this bug could be easily reproduced by doing
"find -exec md5" on large set of files several times consequiently, and then
comparing results. You can see that md5 checksum of the one of the files is
different in the run #3. Most often this happens with big distfiles, like
XFree, jdk etc and only after some amount of previous activity. Memory/CPU/HDD
bug is highly unlikely, as this box often up and running w/o reboot from
release to release, so it looks like glitch in disk cache, fs, soft-updates or
md5.
-Maxim
root@vega# find -H /usr/ports/distfiles -type f -exec md5 {} \; | sort > /tmp/1
root@vega# find -H /usr/ports/distfiles -type f -exec md5 {} \; | sort > /tmp/2
root@vega# find -H /usr/ports/distfiles -type f -exec md5 {} \; | sort > /tmp/3
root@vega# md5 /tmp/1 /tmp/2 /tmp/3
MD5 (/tmp/1) = 8ca51e2ce47c49f8a58776ca4b3567a2
MD5 (/tmp/2) = 8ca51e2ce47c49f8a58776ca4b3567a2
MD5 (/tmp/3) = 61f7ef39f30783d42c9b93dab4695398
root@vega# diff /tmp/2 /tmp/3
129c129
< MD5 (/usr/ports/distfiles/jdk1.1.8_ELF.V1999-11-9.tar.gz) =
07992302128f36c7f802b579e041604c
---
> MD5 (/usr/ports/distfiles/jdk1.1.8_ELF.V1999-11-9.tar.gz) =
a78b523bcc2875a5d0fa8be1e1b73ac3
root@vega# md5 /usr/ports/distfiles/jdk1.1.8_ELF.V1999-11-9.tar.gz
MD5 (/usr/ports/distfiles/jdk1.1.8_ELF.V1999-11-9.tar.gz) =
07992302128f36c7f802b579e041604c
root@vega# md5 /usr/ports/distfiles/jdk1.1.8_ELF.V1999-11-9.tar.gz
MD5 (/usr/ports/distfiles/jdk1.1.8_ELF.V1999-11-9.tar.gz) =
07992302128f36c7f802b579e041604c
root@vega# md5 /usr/ports/distfiles/jdk1.1.8_ELF.V1999-11-9.tar.gz
MD5 (/usr/ports/distfiles/jdk1.1.8_ELF.V1999-11-9.tar.gz) =
07992302128f36c7f802b579e041604c
root@vega# mount
[...]
/dev/ad0s1f on /usr (ufs, NFS exported, local, noatime, soft-updates, writes:
sync 2 async 63, reads: sync 4977 async 13395)
[...]
root@vega# du -d1 /usr/ports/distfiles/
7392 /usr/ports/distfiles/mpich
1 /usr/ports/distfiles/amaya
145 /usr/ports/distfiles/wdm
3513 /usr/ports/distfiles/python
69860 /usr/ports/distfiles/xc
20465 /usr/ports/distfiles/pm3
199 /usr/ports/distfiles/unroff
1841 /usr/ports/distfiles/povray31
949 /usr/ports/distfiles/squid2.3
1 /usr/ports/distfiles/timidity
13 /usr/ports/distfiles/xengine
341295 /usr/ports/distfiles/
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Copyright (c) 1992-2000 The FreeBSD Project.
Copyright (c) 1982, 1986, 1989, 1991, 1993
The Regents of the University of California. All rights reserved.
FreeBSD 4.0-STABLE #9: Tue Apr 4 17:32:40 EEST 2000
root@vega.vega.com:/usr/src/sys/compile/VEGA
Timecounter "i8254" frequency 1193182 Hz
Timecounter "TSC" frequency 100227617 Hz
CPU: Pentium/P54C (100.23-MHz 586-class CPU)
Origin = "GenuineIntel" Id = 0x524 Stepping = 4
Features=0x1bf<FPU,VME,DE,PSE,TSC,MSR,MCE,CX8>
real memory = 41943040 (40960K bytes)
avail memory = 38395904 (37496K bytes)
Preloaded elf kernel "kernel" at 0xc0287000.
Intel Pentium detected, installing workaround for F00F bug
npx0: <math processor> on motherboard
npx0: INT 16 interface
pcib0: <Host to PCI bridge> on motherboard
pci0: <PCI bus> on pcib0
isab0: <Intel 82371AB PCI to ISA bridge> at device 7.0 on pci0
isa0: <ISA bus> on isab0
atapci0: <Intel PIIX4 ATA33 controller> port 0xf000-0xf00f at device 7.1 on pci0
ata0: at 0x1f0 irq 14 on atapci0
pci0: <Intel 82371AB/EB (PIIX4) USB controller> at 7.2 irq 11
chip1: <Intel 82371AB Power management controller> port 0x5000-0x500f at device 7.3 on pci0
ed0: <NE2000 PCI Ethernet (RealTek 8029)> port 0x6500-0x651f irq 10 at device 17.0 on pci0
ed0: address 00:40:05:3b:1c:23, type NE2000 (16 bit)
fdc0: <NEC 72065B or clone> at port 0x3f0-0x3f5,0x3f7 irq 6 drq 2 on isa0
fdc0: FIFO enabled, 8 bytes threshold
fd0: <1440-KB 3.5" drive> on fdc0 drive 0
atkbdc0: <Keyboard controller (i8042)> at port 0x60,0x64 on isa0
atkbd0: <AT Keyboard> irq 1 on atkbdc0
vga0: <Generic ISA VGA> at port 0x3b0-0x3df iomem 0xa0000-0xbffff on isa0
sc0: <System console> on isa0
sc0: VGA <16 virtual consoles, flags=0x200>
sio0 at port 0x3f8-0x3ff irq 4 flags 0x10 on isa0
sio0: type 16550A
sio1 at port 0x2f8-0x2ff irq 3 on isa0
sio1: type 16550A
ad0: 6187MB <FUJITSU MPC3064AT> [13410/15/63] at ata0-master using UDMA33
Mounting root from ufs:/dev/ad0s1a
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