Date: Tue, 28 Jul 1998 00:51:17 -0700 (PDT) From: Matt Dillon <dillon@best.net> To: FreeBSD-gnats-submit@FreeBSD.ORG Subject: kern/7424: biodone: buffer not busy panics Message-ID: <199807280751.AAA15626@flea.best.net>
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>Number: 7424
>Category: kern
>Synopsis: Machine crashes do not occur very often, but when they do occur it's usually a panic on biodone: buffer not busy.
>Confidential: no
>Severity: serious
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Tue Jul 28 01:00:01 PDT 1998
>Last-Modified:
>Originator: Matt Dillon
>Organization:
Best Internet Communications
>Release: FreeBSD 2.2.6-STABLE i386
>Environment:
FreeBSD-stable from CVS (somewhere inbetween 2.2.6, 2.2.7).
FreeBSD-current
All of our boxes use Adaptec 2940UW boards and nearly all of them are
single-cpu PPro-200 motherboards. Boot information is similar to
as shown below. Tagged queueing is enabled.
options AHC_TAGENABLE
options AHC_ALLOW_MEMIO
ahc0 <Adaptec 2940 Ultra SCSI host adapter> rev 0 int a irq 11 on pci0:12:0
ahc0: aic7880 Wide Channel, SCSI Id=7, 16 SCBs
ahc0 waiting for scsi devices to settle
ahc0: target 0 Tagged Queuing Device
(ahc0:0:0): "SEAGATE ST34371W 0484" type 0 fixed SCSI 2
sd0(ahc0:0:0): Direct-Access 4148MB (8496884 512 byte sectors)
sd0(ahc0:0:0): with 5172 cyls, 10 heads, and an average 164 sectors/track
ahc0: target 1 Tagged Queuing Device
(ahc0:1:0): "SEAGATE ST19171W 0023" type 0 fixed SCSI 2
sd1(ahc0:1:0): Direct-Access 8683MB (17783112 512 byte sectors)
sd1(ahc0:1:0): with 5268 cyls, 20 heads, and an average 168 sectors/track
ahc0: target 2 Tagged Queuing Device
(ahc0:2:0): "SEAGATE ST19171W 0023" type 0 fixed SCSI 2
sd2(ahc0:2:0): Direct-Access 8683MB (17783112 512 byte sectors)
sd2(ahc0:2:0): with 5268 cyls, 20 heads, and an average 168 sectors/track
>Description:
I'm submitting this bug report even though I don't have a hard
backtrace. Unfortuntely, as you can see, the nature of the panic
generally precludes getting a dump. I figure it's good to keep the
PR in the bug list. I've set the severity to to serious since it is
a crash, but the priority to low because it only happens once a month
per machine or so... but it's an important stability issue because
'biodone: buffer not busy' panics are responsible for most of the
crashes we get these days. If it could be fixed, it would considerably
increase machine reliability.
Our -stable machines, around 40 of them, each tend to crash around
once a month (so we get about a crash a day). i.e. they do not
crash very often. But when they do, many of the crashes are due to
biodone: buffer not busy panics. These crashes are sometimes preceded
by kernel printf's relating to the SCSI subsystem.
We have also seen this crash on our FreeBSD-current test box.
-Matt
(FROM CONSOLE LOGS)
ahc0: WARNING no command for scb 4 (cmdcmplt)
QOUTCNT == 8
panic: biodone: buffer not busy
Debugger("panic")
db> trace
_Debugger(f0113258) at _Debugger+0x35
_panic(f012ebe9,f1adb080,f10a7c00,f3b51114,f1aabfd0) at _panic+0x5a
_biodone(f3b51114,f1adb080,f10a7c00,1,f1adb080) at _biodone+0x30
_scsi_done(f1adb080,f1aafa60,f1ab0800,40000,f01db4e1) at _scsi_done+0x84
_ahc_done(f1ab0800,f1aafa60) at _ahc_done+0x155
_ahc_intr(f1ab0800,0,27,efbf0027,40000) at _ahc_intr+0x1c7
Xresume11() at Xresume11+0x2b
--- interrupt, eip = 0xa5c4, esp = 0xefbffff0, ebp = 0xefbfb8b8 ---
db> pani
panic: from debugger
dumping to dev 401, offset 786432
dump panic: biodone: buffer not busy
dumping to dev 401, offset 786432
dump device not ready
Automatic reboot in 15 seconds - press a key on the console to abort
>How-To-Repeat:
The panics cannot be deterministically reproduced, but occur
around once a month per machine.
>Fix:
>Audit-Trail:
>Unformatted:
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