DragonFlyBSD

:New submission from VOROSKOI Andras <voroskoi@gmail.com>:
:
:DragonFly 1.13-DEVELOPMENT #1: Mon May 19 23:26:51 CEST 2008 crashes on a s=
:imple
:mount_cd9660 /dev/cd0 /mnt/cdrom.
:
:The last commit in this kernel is:
:http://repo.or.cz/w/dragonfly.git?a=3Dcommit;h=3Da13a97e518b44d453d9329dbb0=
:909b27c730803d
:
:Here is the error message:
:
:Fatal trap 12: page fault while in kernel mode
:fault virtual address =3D 0x8
:fault code =3D supervisor read, page not present
:instruction pointer =3D 0x8:0xc02d3e15
:stack pointer =3D 0x10:0xca3ed6c8
:frame pointer =3D 0x10:0xca3ed744
:code segment =3D base 0x0, limet 0xfffff, type 0x1b
: =3D DPL 0, pres 1, def32 1, gran 1
:processor eflags =3D intercept enabled, resume, IOPL =3D 0
:current process =3D 7660 (mount_cd9660)
:current thread =3D pri 10
:
:kernel: type 12 trap, code 0
:Stopped at dsioctl+0x39: movl 0x8(%esi),%ebx
:db> trace
:dsioctl(snip) at dsioctl+0x39
:cdcheckmedia(snip) at cdcheckmedia+0x246
:cdopen(snip) at cdopen+0xd0
:dev_dopen(snip) at dev_dopen+0x2f
:diskopen(snip) at diskopen+0x7d
:...
:sys_open(snip) at sys_open+0x32
:syscall2(snip) at syscall2+0x1ec
:Xint0x80_syscall() at Xint0x80_syscall+0x36
:
:I was only able to write it down to a piece of paper, hopefully i did not m=
:ake
:any typo. Also i was lazy to add the memory addresses too for the functions=
:, let
:me know if you miss them or anything else.
:
:One more thing: using /dev/acd0 works fine.

That's excellent information.  I haven't been able to reproduce the
    problem, though, I seem to be able to mount from /dev/cd0 ok.  I have
    some suspicions, though, considering where it is panicing.

What kind of CD did you have in the drive?  A DragonFly CD or something
    else?  Did you perform any other actions prior to doing the
    mount_cd9660?  Such as mounting it (or trying to mount it) via some
    other path?

Can you reproduce the problem and perhaps get a kernel core dump?

-Matt

No, i can crash it right after logging in.
It's a simple data cd with some mp3, but i can reproduce it with my
dfly-1.12.2 cd too. (Both cd is rewritable.)

Yes, it's always reproductable. You can find the core dump here:
http://frugalware.org/~voroskoi/dfly/dfly-mount_cd9660-coredump.tar.bz2

...

Hi Andras. I can't help you with your crash but the 'repo.org.cz' caught my attention.
Simon, are you updating that git repository regularly now? If so I'll start using it
myself.

The crash dump is really helpful. I have reproduced it. What is
happening is that cdcheckmedia() is being called before the slice
table is getting set up. I think adding some simple conditionals to
those dsioctl()'s will solve the problem.

I should have a fix for the mount_cd9660 issue committed today.

-Matt
                    Matthew Dillon 
                    <dillon@backplane.com>

More precisely, the commit on the 18th updating the CAM code is setting
CD_FLAG_OPEN early, causing dsioctl() to improperly be called before the
slice table has been installed.

-Matt
                    Matthew Dillon 
                    <dillon@backplane.com>

Bug in CAM, fix committed.