From: Mark Wielaard <mjw@redhat.com>
To: Torsten Polle <Torsten.Polle@gmx.de>
Cc: systemtap@sourceware.org
Subject: Re: Prelinking on ARM with Debug Link
Date: Mon, 11 Apr 2016 21:02:00 -0000 [thread overview]
Message-ID: <20160411210157.GA4882@blokker.redhat.com> (raw)
In-Reply-To: <D9911106-AB0E-4947-ADC9-F8CFB8700226@gmx.de>
On Mon, Apr 11, 2016 at 08:47:00PM +0200, Torsten Polle wrote:
> Iâve checked your patch. As a result the backtrace calculations
> break in my environment.
I assume this is an in-kernel backtrace, does it involve kernel modules?
Or is it a user backtrace, executable only? shared libraries?
Could you show a probe script and example backtrace?
Please do include some verbose output. If you can provide the output
of stap -DDEBUG_UNWIND=1 that might be helpful.
> Iâve therefore instrumented adjustStartLoc() as follows:
>
> if (is_ehframe) {
> printk(KERN_ERR "eh: s=%lu, v=%lu, l=%lu\n", startLoc, vm_addr, s->sec_load_offset);
> return startLoc + vm_addr;
> }
> else {
> printk(KERN_ERR "no eh: s=%lu, v=%lu, l=%lu\n", startLoc, vm_addr, s->sec_load_offset);
> return startLoc + vm_addr - s->sec_load_offset;
> }
>
> As a result I get the following output:
>
> [ 1215.876537] no eh: s=297684, v=1307279360, l=4294962112
> [ 1215.876542] no eh: s=297532, v=1307279360, l=4294962112
> [ 1215.876546] no eh: s=297568, v=1307279360, l=4294962112
> [ 1215.876551] no eh: s=297612, v=1307279360, l=4294962112
> [ 1215.876555] no eh: s=297612, v=1307279360, l=4294962112
> [ 1215.876560] no eh: s=297612, v=1307279360, l=4294962112
>
> This means that the non-ehframe path is taken and that sec_load_offset
> is non-zero.
And that calculation wraps around because it is all unsigned.
I admit I don't understand what this calculation represents.
Cheers,
Mark
next prev parent reply other threads:[~2016-04-11 21:02 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-01 19:29 Torsten Polle
2016-02-09 20:55 ` Torsten Polle
2016-02-10 16:17 ` Mark Wielaard
2016-02-10 20:12 ` Torsten Polle
2016-02-10 20:35 ` Mark Wielaard
2016-02-11 10:49 ` Aw: " Torsten Polle
2016-02-16 10:08 ` Mark Wielaard
2016-02-16 20:46 ` Torsten Polle
2016-02-18 16:21 ` Mark Wielaard
2016-02-22 21:45 ` Torsten Polle
2016-02-23 16:46 ` Mark Wielaard
2016-02-23 22:16 ` Torsten Polle
2016-02-28 20:51 ` Torsten Polle
2016-03-30 20:05 ` Torsten Polle
2016-04-01 13:07 ` Mark Wielaard
2016-04-01 21:19 ` Torsten Polle
2016-04-05 13:44 ` Mark Wielaard
2016-04-06 20:45 ` Torsten Polle
2016-04-06 21:56 ` Mark Wielaard
2016-04-11 18:47 ` Torsten Polle
2016-04-11 21:02 ` Mark Wielaard [this message]
2016-04-12 20:26 ` Torsten Polle
2016-04-13 9:25 ` Mark Wielaard
2016-04-13 14:36 ` Aw: " Torsten Polle
-- strict thread matches above, loose matches on Subject: below --
2015-12-01 7:26 Torsten Polle
2015-11-25 20:52 Torsten Polle
2015-11-26 10:33 ` Mark Wielaard
2015-11-26 22:05 ` Torsten Polle
2015-11-27 8:05 ` Mark Wielaard
2015-11-27 12:57 ` Torsten Polle
2015-11-27 15:06 ` Mark Wielaard
2015-11-27 16:34 ` Mark Wielaard
2015-11-27 20:08 ` Torsten Polle
2015-11-27 20:01 ` Torsten Polle
2015-11-30 19:26 ` David Smith
2015-12-01 20:10 ` Torsten Polle
2015-12-10 19:00 ` David Smith
2015-12-10 19:45 ` Torsten Polle
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