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Re: Can't set statement probe in self-built linux-4.4
- From: Chris Dunlop <chris at onthe dot net dot au>
- To: Josh Stone <jistone at redhat dot com>
- Cc: "Frank Ch. Eigler" <fche at redhat dot com>, systemtap at sourceware dot org
- Date: Fri, 15 Jul 2016 03:29:54 +1000
- Subject: Re: Can't set statement probe in self-built linux-4.4
- Authentication-results: sourceware.org; auth=none
- References: <20160630075744.GA3637@onthe.net.au> <y0mk2h6vi3c.fsf@fche.csb> <20160630223410.GB16787@onthe.net.au> <20160701005738.GF3830@redhat.com> <20160701034302.GA23357@onthe.net.au> <20160714160842.GA20289@onthe.net.au> <bae936b3-3675-e463-da84-fbb3cc857ae4@redhat.com>
On Thu, Jul 14, 2016 at 10:20:56AM -0700, Josh Stone wrote:
> On 07/14/2016 09:08 AM, Chris Dunlop wrote:
> > On Fri, Jul 01, 2016 at 01:43:02PM +1000, Chris Dunlop wrote:
> > Any ideas?
>
> $ grep DEBUG_INFO .config
> CONFIG_DEBUG_INFO=y
> # CONFIG_DEBUG_INFO_REDUCED is not set
> CONFIG_DEBUG_INFO_SPLIT=y
> CONFIG_DEBUG_INFO_DWARF4=y
>
> I think SPLIT is the problem. This puts all debuginfo into separate
> .dwo objects, and then vmlinux itself only contains DW_AT_GNU_dwo_name
> references from each CU.
>
> There's no dwo_name support at all in elfutils yet, thus stap doesn't
> support it either.
>
> The function probe that you are getting is based only on the symbol
> table, which is why you're not seeing any arguments either. And
> statement probes aren't available at all without working debuginfo.
OK, that sounds like it explains the problem.
I'll remove the SPLIT and let you know...
Thanks!
Chris