Fatal trap 12: page fault while in kernel mode

[Kris Kennaway]

On Mon, Apr 23, 2007 at 05:35:47PM +0200, Kai wrote:
> On Thu, Apr 19, 2007 at 02:33:29PM +0200, Kai wrote:
> > On Wed, Apr 11, 2007 at 12:53:32PM +0200, Kai wrote:
> > > 
> > > Hello all,
> > > 
> > > We're running into regular panics on our webserver after upgrading
> > > from 4.x to 6.2-stable:
> > 
> 
> Hi all,
> 
> To continue this story, a colleague wrote a small program in C that launches
> 40 threads to randomly append and write to 10 files on an NFS mounted
> filesystem. 
> 
> If I keep removing the files on one of the other machines in a while loop,
> the first system panics:
> 
> Fatal trap 12: page fault while in kernel mode
> cpuid = 1; apic id = 01
> fault virtual address   = 0x34
> fault code              = supervisor read, page not present
> instruction pointer     = 0x20:0xc06bdefa
> stack pointer           = 0x28:0xeb9f69b8
> frame pointer           = 0x28:0xeb9f69c4
> 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         = 73626 (nfscrash)
> trap number             = 12
> panic: page fault
> cpuid = 1
> Uptime: 3h2m14s
> 
> Sounds like a nice denial of service problem. I can hand the program to
> developers on request.

Please send it to me.  Panics are always much easier to get fixed if
they come with a test case that developer can use to reproduce it.

Kris
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