Re: Panic on -CURRENT after LDT changes

Thanks,  Attilio and I will look at this right away.

Jeff

On Wed, 23 May 2007, Joe Marcus Clarke wrote:

> On a -CURRENT build today with Jeff's LDT locking changes, I get an
> instant, reproducible panic by doing:
>
> # cd /usr/src
> # make -DNO_CLEAN buildworld
>
> Backing out the LDT changes to /sys/i386/i386/*machdep* corrects the
> problem.  Here is a dmesg and backtrace.  In frame 6, it appears mdp is
> NULL (i.e. td->td_proc->p_md = 0x0).
>
> http://www.marcuscom.com/downloads/JCLARKE-PC_dump.txt
>
> Unread portion of the kernel message buffer:
> kernel trap 12 with interrupts disabled
>
>
> Fatal trap 12: page fault while in kernel mode
> fault virtual address   = 0x4
> fault code              = supervisor read, page not present
> instruction pointer     = 0x20:0xc0723195
> stack pointer           = 0x28:0xe768dbf4
> frame pointer           = 0x28:0xe768dc20
> code segment            = base 0x0, limit 0xfffff, type 0x1b
>                        = DPL 0, pres 1, def32 1, gran 1
> processor eflags        = resume, IOPL = 0
> current process         = 1025 (make)
> trap number             = 12
> panic: page fault
> Uptime: 2m37s
> Physical memory: 2022 MB
> Dumping 65 MB: 50 34 18 2
>
> #0  doadump () at pcpu.h:172
> #1  0xc0562c93 in boot (howto=260)
> at /usr/src/sys/kern/kern_shutdown.c:409
> #2  0xc0562f18 in panic (fmt=Variable "fmt" is not available.
> #3  0xc07240b2 in trap_fatal (frame=0xe768dbb4, eva=4)
>    at /usr/src/sys/i386/i386/trap.c:876
> #4  0xc07249a3 in trap (frame=0xe768dbb4)
> at /usr/src/sys/i386/i386/trap.c:276
> #5  0xc070de5b in calltrap () at /usr/src/sys/i386/i386/exception.s:139
> #6  0xc0723195 in i386_ldt_grow (td=Variable "td" is not available.
> )
>    at /usr/src/sys/i386/i386/sys_machdep.c:704
> #7  0xc072350a in i386_set_ldt (td=0xc4fccbd0, uap=0xe768dc68,
>    descs=0xe76f3000) at /usr/src/sys/i386/i386/sys_machdep.c:631
> #8  0xc0723a44 in sysarch (td=0xc4fccbd0, uap=0xe768dcfc)
>    at /usr/src/sys/i386/i386/sys_machdep.c:134
> #9  0xc0724645 in syscall (frame=0xe768dd38)
>    at /usr/src/sys/i386/i386/trap.c:1016
> #10 0xc070dec0 in Xint0x80_syscall ()
> at /usr/src/sys/i386/i386/exception.s:196
> #11 0x00000033 in ?? ()
>
> Joe
>
> -- 
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>