Date: Sun, 7 Jan 1996 14:30:21 -0700 From: rlenk@widget.xmission.com To: FreeBSD-gnats-submit@freebsd.org Subject: kern/938: processes sleeping on "newbuf" indefinitely Message-ID: <199601072130.OAA00364@widget.xmission.com> Resent-Message-ID: <199601072140.NAA17404@freefall.freebsd.org>
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>Number: 938
>Category: kern
>Synopsis: after heavy disk I/O, processes sleep on "newbuf" indefinitely
>Confidential: no
>Severity: critical
>Priority: high
>Responsible: freebsd-bugs
>State: open
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Sun Jan 7 13:40:02 PST 1996
>Last-Modified:
>Originator: Ron Lenk
>Organization:
A private FreeBSD site
>Release: FreeBSD 2.1-STABLE i386
>Environment:
FreeBSD 2.1-STABLE, kernel sources obtained via FTP from ftp.freebsd.org on
Sun Jan 7, at about 10:00 MST.
dmesg output:
FreeBSD 2.1-STABLE #0: Sun Jan 7 12:33:12 MST 1996
rlenk@widget.xmission.com:/usr/src/sys/compile/WIDGET
CPU: 60-MHz Pentium 510\60 (Pentium-class CPU)
Origin = "GenuineIntel" Id = 0x517 Stepping=7
Features=0x1bf<FPU,VME,PSE,MCE,CX8,APIC>
real memory = 33554432 (32768K bytes)
avail memory = 30621696 (29904K bytes)
ahc0: <Adaptec 284X SCSI host adapter> at 0x1c00-0x1cff irq 11 on isa
ahc0: Using Edge Triggered Interrupts
ahc0: aic7770 <= Rev C, Single Channel, SCSI Id=7, 4 SCBs
ahc0: Probing channel A
ahc0 waiting for scsi devices to settle
ahc0: target 0 synchronous at 10.0MHz, offset = 0xf
ahc0: target 0 Tagged Queuing Device
(ahc0:0:0): "MICROP 2210-09MQ1001901 HQ30" type 0 fixed SCSI 2
sd0(ahc0:0:0): Direct-Access 1008MB (2065250 512 byte sectors)
sd0(ahc0:0:0): with 2372 cyls, 9 heads, and an average 96 sectors/track
ahc0: target 1 synchronous at 5.0MHz, offset = 0xf
(ahc0:1:0): "SyQuest SQ3270S 2_04" type 0 removable SCSI 2
sd1(ahc0:1:0): Direct-Access 256MB (524288 512 byte sectors)
sd1(ahc0:1:0): with 3140 cyls, 2 heads, and an average 83 sectors/track
(ahc0:2:0): "TEXEL CD-ROM DM-XX28 3.05" type 5 removable SCSI 2
cd0(ahc0:2:0): CD-ROM
cd0(ahc0:2:0): NOT READY asc:3a,0 Medium not present
can't get the size
Probing for devices on the ISA bus:
sc0 at 0x60-0x6f irq 1 on motherboard
sc0: VGA color <16 virtual consoles, flags=0x0>
ed0 at 0x280-0x28f irq 9 maddr 0xd8000 msize 8192 on isa
ed0: address 02:60:8c:3f:30:b8, type 3c503 (8 bit)
bpf: ed0 attached
sio0 at 0x3f8-0x3ff irq 4 on isa
sio0: type 16550A
sio1 at 0x2f8-0x2ff irq 3 on isa
sio1: type 16550A
lpt0 at 0x378-0x37f irq 7 on isa
lpt0: Interrupt-driven port
lp0: TCP/IP capable interface
bpf: lp0 attached
mse0 at 0x23c irq 5 on isa
fdc0 at 0x3f0-0x3f7 irq 6 drq 2 on isa
fdc0: NEC 72065B
fd0: 1.44MB 3.5in
fd1: 1.2MB 5.25in
npx0 on motherboard
npx0: INT 16 interface
BIOS Geometries:
0:03ef3f20 0..1007=1008 cylinders, 0..63=64 heads, 1..32=32 sectors
0 accounted for
bpf: lo0 attached
bpf: ppp0 attached
bpf: ppp1 attached
bpf: sl0 attached
bpf: sl1 attached
bpf: tun0 attached
bpf: tun1 attached
sd0s1: type 0xa5, start 0, end = 2065249, size 2065250 : OK
kernel configuration file:
machine "i386"
cpu "I586_CPU"
ident WIDGET
maxusers 64
options INET
options FFS
options MFS
options NFS
options MSDOSFS
options "CD9660"
options PROCFS
options "COMPAT_43"
options "SCSI_DELAY=5"
options BOUNCE_BUFFERS
options UCONSOLE
options SYSVSHM
options SYSVSEM
options SYSVMSG
options "AUTO_EOI_1"
options "AUTO_EOI_2"
options DUMMY_NOPS
options AHC_TAGENABLE
options KTRACE
options "CHILD_MAX=128"
options "OPEN_MAX=128"
options DDB
config kernel root on sd0
controller isa0
controller eisa0
controller fdc0 at isa? port "IO_FD1" bio irq 6 drq 2 vector fdintr
disk fd0 at fdc0 drive 0
disk fd1 at fdc0 drive 1
controller ahc0
controller scbus0
device sd0
device cd0
device sc0 at isa? port "IO_KBD" tty irq 1 vector scintr
device npx0 at isa? port "IO_NPX" irq 13 vector npxintr
device sio0 at isa? port "IO_COM1" tty irq 4 vector siointr
device sio1 at isa? port "IO_COM2" tty irq 3 vector siointr
device lpt0 at isa? port? tty irq 7 vector lptintr
device mse0 at isa? port 0x23c tty irq 5 vector mseintr
device ed0 at isa? port 0x280 net irq 9 iomem 0xd8000 vector edintr
pseudo-device loop
pseudo-device ether
pseudo-device log
pseudo-device sl 2
pseudo-device ppp 2
pseudo-device tun 2
pseudo-device pty 64
pseudo-device snp 2
pseudo-device bpfilter 8
pseudo-device speaker
pseudo-device gzip
pseudo-device vn
>Description:
After periods of heavy disk I/O, all disk activity will eventually stop,
leaving the machine in a semi-hung condition. The only way to recover is
do a full hardware reset, with the big red button. :)
The easiest way to cause the hang is to do something such as:
dd if=/dev/zero of=bigfile
dd if=bigfile of=/dev/null
Building a kernel with DDB, and doing a "ps" after escaping to the
debugger reveals that the "dd" process is waiting on "newbuf". If
I do a "continue", then escape to the debugger again after several
minutes, more of the processes, such as cron, syslogd, etc, are also
waiting on "newbuf".
>How-To-Repeat:
See above.
>Fix:
Unknown
>Audit-Trail:
>Unformatted:
help
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