[issue1016] mount_cd9660 crashes the kernel

[Matthew Dillon]

:New submission from VOROSKOI Andras <voroskoi at 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