Kernel panic in 6.0 revisited

John Baldwin jhb at FreeBSD.org
Tue Sep 7 12:57:17 PDT 2004


On Saturday 04 September 2004 12:57 am, Joe Marcus Clarke wrote:
> A few days ago, I reported a kernel panic in HEAD while building
> packages on my tinderbox machine.  I was unable to get a core dump fro
> that crash, and after switching from ULE to 4BSD, I had thought it had
> gone away.
>
> Well, today, the machine panicked twice.  It was the same panic both
> times, and the same panic I got a few days ago.  This time, however, I
> was able to get a core dump.  Here is the panic message:
>
> Fatal trap 12: page fault while in kernel mode
> cpuid = 0; apic id = 00
> fault virtual address   = 0x1c
> fault code              = supervisor write, page not present
> instruction pointer     = 0x8:0xc0533d07
> stack pointer           = 0x10:0xf5f30a4c
> frame pointer           = 0x10:0xf5f30a58
> 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         = 27441 (cpp0)
> Stopped at  vfs_vmio_release+0x1b: lock cmpxchgl %ecx,0x1c(%edx)
>
> And here is the output of "l *vfs_vmio_release+0x1b":
>
> 0xc0533d07 is in vfs_vmio_release (atomic.h:154).
> 149     static __inline int
> 150     atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)
> 151     {
> 152             int res = exp;
> 153
> 154             __asm __volatile (
> 155             "       " __XSTRING(MPLOCKED) " "
> 156             "       cmpxchgl %1,%2 ;        "
> 157             "       setz    %%al ;          "
> 158             "       movzbl  %%al,%0 ;       "
>
> Kernel config is at http://www.marcuscom.com/downloads/FUGU.kernel and
> the dmesg output is at http://www.marcuscom.com/downloads/FUGU.dmesg
>
> Let me know if you need anything else.  Thanks.

How about 'l *0xc0533d00' to try and figure out which function is calling 
that.  Also, do you have INVARIANTS turned on?

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org


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