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Subject: Re: [FTRACE] Enabling function_graph causes OOPS
From: Steven Rostedt <rostedt@goodmis.org>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Date: Sun, 13 Sep 2009 09:21:00 -0400
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On Sun, 2009-09-13 at 14:37 +1000, Benjamin Herrenschmidt wrote:
> On Sun, 2009-09-13 at 00:07 -0400, Steven Rostedt wrote:
> >                        982: R_PPC64_ADDR16_HIGHEST
> > ftrace_return_to_handler
> >  984:   60 84 00 00     ori     r4,r4,0
> >                         986: R_PPC64_ADDR16_HIGHER
> > ftrace_return_to_handler
> >  988:   78 84 07 c6     rldicr  r4,r4,32,31
> >  98c:   64 84 00 00     oris    r4,r4,0
> >                         98e: R_PPC64_ADDR16_HI
> > ftrace_return_to_handler
> >  990:   60 84 00 00     ori     r4,r4,0
> >                         992: R_PPC64_ADDR16_LO
> > ftrace_return_to_handler
> >  994:   e8 44 00 08     ld      r2,8(r4)
> >  998:   48 00 00 01     bl      998 <.mod_return_to_handler+0x30>
> >                         998:
> > R_PPC64_REL24      .ftrace_return_to_handler
> >  99c:   60 00 00 00     nop
> >  9a0:   7c 68 03 a6     mtlr    r3
> 
> .../...
> 
> > Something is totally messed up here.
> 
> Could it be that we don't handle R_PPC64_ADDR16_* relocs in
> arch/powerpc/kernel/modules/module_64.c ?
> 
> Sachin, do you see a bunch of "Unknown ADD relocation" in your dmesg ?

Ben,

The thing is, this is kernel proper. This code is in entry_64.S not in
the module code.

-- Steve