Re: Unkillable process in last git -- 100% reproducible

[Paolo Ornati]

On Wed, 28 Jun 2006 15:09:43 +0200
Paolo Ornati <ornati@xxxxxxxxxxxxx> wrote:

> On Wed, 28 Jun 2006 14:53:49 +0200
> Paolo Ornati <ornati@xxxxxxxxxxxxx> wrote:
> 
> > > [  430.083347] localedef     R  running task       0  8577   8558  8578               (NOTLB)
> > > [  430.083352] gzip          X ffff81001e612ee0     0  8578   8577                     (L-TLB)
> > > [  430.083358] ffff81001395bef8 ffff81001fd1a310 0000000000000246 ffff81001e612ee0 
> > > [  430.083362]        ffff81001e4c0080 ffff81001e612ee0 ffff81001e4c0258 0000000000000001 
> > > [  430.083366]        0000000000000046 0000000000000046 ffff81001395bf18 0000000000000010 
> > > [  430.083370] Call Trace: <ffffffff80227f6f>{do_exit+2378} <ffffffff802628e9>{vfs_write+288}
> > > [  430.083379]        <ffffffff80228065>{sys_exit_group+0} <ffffffff80209806>{system_call+126}
> > 
> > do_exit() -- kernel/exit.c
> > 
> > 0xffffffff80227f66 <do_exit+2369>:      mov    %rax,0x18(%rbp)
> > 0xffffffff80227f6a <do_exit+2373>:      callq  0xffffffff8048b850 <schedule>
> > 0xffffffff80227f6f <do_exit+2378>:      ud2a
> > 0xffffffff80227f71 <do_exit+2380>:      pushq  $0xffffffff804b7821
> > 0xffffffff80227f76 <do_exit+2385>:      retq   $0x3ba
> > 0xffffffff80227f79 <do_exit+2388>:      jmp    0xffffffff80227f79 <do_exit+2388>
> 
> 
> that is the end of the function:
> 
> ...
>         schedule();
>         BUG();
>         /* Avoid "noreturn function does return".  */
>         for (;;) ;
> }
> 
> 
> So the questions are two:
> 
> 1) why schedule() didn't work?
> 
> 2) why the process is looping around "ud2a" (placed by BUG()) and
> presumibly throwing a lot of "invalid opcode" exceptions?

It seems that the first mail didn't hit LKML (maybe it was too big),
here it is (stripped):

------------------------------------------------------------------------
Running "localedef" triggers an infinite loop in kernel mode (or
something) --> localdef becomes unkillable.

This is dmesg after pressing ALT+SysRQ+T three times:

[CUT]

KERNEL:

--
	Paolo Ornati
	Linux 2.6.17-ga39727f2-dirty on x86_64
	                      ^^^^^^^

The -dirty is because of a fix to PS2 Keyboard auto-repeat, nothing else.
------------------------------------------------------------------------


Full config attached.

Attachment: config.gz
Description: GNU Zip compressed data