Date: Fri, 24 Aug 2001 14:07:28 -0400 (EDT) From: Mikhail Teterin <mi@aldan.algebra.com> To: current@freebsd.org Cc: n_hibma@freebsd.org Subject: another panic (mix ppp and usb to taste) Message-ID: <200108241807.f7OI7Vd00967@aldan.algebra.com>
next in thread | raw e-mail | index | archive | help
As I was trying to let the Palm Pilot connect to my desktop
through usb using PPP, I tried to run
/usr/sbin/ppp -quiet -direct -nat < /dev/ugen0
While, perhaps, not the right way to do what I want (what is? aren't
serial devices the simplest?), it should not panic (nothing should
really). But it does, and quite repeatedly (some more comments after
the trace):
IdlePTD 4984832
initial pcb at 3db040
panicstr: bwrite: buffer is not busy???
panic messages:
---
Fatal trap 12: page fault while in kernel mode
cpuid = 0; lapic.id = 01000000
fault virtual address = 0x3
fault code = supervisor read, page not present
instruction pointer = 0x8:0xc01d5a0b
stack pointer = 0x10:0xce7f1c4c
frame pointer = 0x10:0xce7f1c58
code segment = base 0x0, limit 0xfffff, type 0x1b
= DPL 0, pres 1, def32 1, gran 1
processor eflags = interrupt enabled, resume, IOPL = 0
current process = 442 (ppp)
trap number = 12
panic: page fault
cpuid = 0; lapic.id = 01000000
boot() called on cpu#0
syncing disks... panic: bwrite: buffer is not busy???
cpuid = 0; lapic.id = 01000000
boot() called on cpu#0
Uptime: 10m14s
dumping to dev da0b, offset 131200
dump ....... 2 1 0
---
[...]
#12 0xc030b0bc in trap (frame={tf_fs = -1071644648, tf_es = -830734320,
tf_ds = 16777232, tf_edi = 64, tf_esi = 0, tf_ebp = -830530472,
tf_isp = -830530504, tf_ebx = -1049243648, tf_edx = -1049243428,
tf_ecx = 34, tf_eax = 0, tf_trapno = 12, tf_err = 0,
tf_eip = -1071818229, tf_cs = 8, tf_eflags = 66178,
tf_esp = -830530412, tf_ss = -1049288448})
at ../../../i386/i386/trap.c:405
#13 0xc01d5a0b in ugenpoll (dev=0xc1752100, events=64, p=0xce7abb80)
at ../../../dev/usb/ugen.c:1369
#14 0xc01ed604 in spec_poll (ap=0xce7f1c94)
at ../../../fs/specfs/spec_vnops.c:333
#15 0xc01ed27d in spec_vnoperate (ap=0xce7f1c94)
at ../../../fs/specfs/spec_vnops.c:119
#16 0xc0252333 in vn_poll (fp=0xc17328c0, events=64, cred=0xc1734700,
p=0xce7abb80) at vnode_if.h:381
#17 0xc0228b8b in selscan (p=0xce7abb80, ibits=0xce7f1d48,
obits=0xce7f1d3c, nfd=1) at ../../../sys/file.h:192
#18 0xc02286b5 in select (p=0xce7abb80, uap=0xce7f1f80)
at ../../../kern/sys_generic.c:772
#19 0xc030bf2d in syscall (frame={tf_fs = 47, tf_es = 47, tf_ds = 47,
tf_edi = 134842880, tf_esi = 134842880, tf_ebp = 0,
tf_isp = -830529580, tf_ebx = 3, tf_edx = 134996480,
tf_ecx = 134996352, tf_eax = 93, tf_trapno = 12, tf_err = 2,
tf_eip = 673178596, tf_cs = 31, tf_eflags = 643,
tf_esp = -1077937708, tf_ss = 47}) at ../../../i386/i386/trap.c:1129
(kgdb) up 13
#13 0xc01d5a0b in ugenpoll (dev=0xc1752100, events=64, p=0xce7abb80)
at ../../../dev/usb/ugen.c:1369
1369 switch (sce->edesc->bmAttributes & UE_XFERTYPE) {
(kgdb) p sce
$1 = (struct ugen_endpoint *) 0x0
(kgdb) l
1364 printf("ugenpoll: no pipe\n");
1365 return (EIO);
1366 }
1367 #endif
1368 s = splusb();
1369 switch (sce->edesc->bmAttributes & UE_XFERTYPE) {
1370 case UE_INTERRUPT:
1371 if (events & (POLLIN | POLLRDNORM)) {
1372 if (sce->q.c_cc > 0)
1373 revents |= events & (POLLIN | POLLRDNORM);
(kgdb) p events
$3 = 64
(kgdb) p s
No symbol "s" in current context.
(kgdb) p revents
$5 = 0
What I don't understand, is -- there is a check, just a few lines
above:
if (sce == NULL)
return (EINVAL);
How come it is not being caught there? Thanks,
--
|\__-----__/|
_____/ ::::: :::\_____
'__--( ::::::::..::)--__` -mi
If you have a / _- \/ :::::::\/ -_
serious knowledge / / :. .::::\ \
about computers -- | ::::::::::::| Ok, let's say you broke
keep it in a secret! _|/ ::::____::\|_ the wall with your head
"Rules of dating", / /:::::/:_::\::\:.\ What are you going to
'Playboy', ? 1994 | :| ..:(_/ \::|::|::| do in the next cell?
| :|:::::. ::|: |::|.:| Stanislaw J. Lec
\ |:: :::_/::/: :|:/
((___\____\____/___/___))
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-current" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200108241807.f7OI7Vd00967>