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From: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
 linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] Remove kretprobe_trampoline_holder.
Date: Wed, 30 Mar 2016 15:38:07 -0300
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Am Mittwoch, 30 M=E4rz 2016, 20:09:36 schrieb Michael Ellerman:
> On Wed, 2016-03-30 at 13:34 +0530, Naveen N. Rao wrote:
> > On 2016/03/29 08:35PM, Thiago Jung Bauermann wrote:
> > > Am Dienstag, 29 M=E4rz 2016, 14:31:34 schrieb Michael Ellerman:
> > > > On Mon, 2016-03-28 at 17:06 -0300, Thiago Jung Bauermann wrote:=

> > > > > With this patch, all vmlinux symbols match /proc/kallsyms and=
 the
> > > > > testcase passes.
> > > >=20
> > > > Have you tested this on an LE system?
> > >=20
> > > No, I was focusing on ppc64 BE.
> >=20
> > Which kernel did you use? I don't see this with the latest 4.6.0-rc=
1.
>=20
> Yeah I can't reproduce the perf test failure either.

I can still reproduce on 4.6.0-rc1.

> Not sure what's going on?

Try disabling CONFIG_FUNCTION_TRACER. The test failure happens when .kr=
etprobe_trampoline_holder and
kretprobe_trampoline have the same address. If that option is enabled, =
the symbols have different addresses:

$ eu-readelf -s /boot/vmlinux-4.6.0-rc1-dirty | grep kretprobe_tramp   =
                                                =20
 2479: c000000000ef1d68     24 NOTYPE  LOCAL  DEFAULT       37 kretprob=
e_trampoline_holder
 2480: c000000000043ab0     40 FUNC    LOCAL  DEFAULT        1 .kretpro=
be_trampoline_holder
86903: c000000000043ac4      0 NOTYPE  GLOBAL DEFAULT        1 kretprob=
e_trampoline
$ grep kretprobe_tramp /proc/kallsyms
c000000000043ab0 t .kretprobe_trampoline_holder
c000000000043ac4 T kretprobe_trampoline
c000000000ef1d68 d kretprobe_trampoline_holder

--=20
[]'s
Thiago Jung Bauermann
IBM Linux Technology Center